matplotlibcpp.h

//
// Wishlist:
// * (WIP) Make work for Eigen Vectors and Matrices
// * export functions in different files for better structure
// * make plot(y) work with x of unsigned type, or get to the bottom of that
//   problem at least
// * errorbar for xerr and yerr
// * errorbar for yerr of shape (2, N)
//
// Changed:
// * Implement a better way for named_plot, maybe just as additional
//   method with extra keyword
// * add location keyword for legend
//

#pragma once

#include <algorithm>
#include <array>
#include <cstdint> // <cstdint> requires c++11 support
#include <functional>
#include <iostream>
#include <map>
#include <numeric>
#include <stdexcept>
#include <vector>
#include <sstream>

#include <Python.h>

#ifndef WITHOUT_NUMPY
#define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION
#include <numpy/arrayobject.h>
#endif // WITHOUT_NUMPY

#if PY_MAJOR_VERSION >= 3
#define PyString_FromString PyUnicode_FromString
#define PyInt_FromLong PyLong_FromLong
#define PyString_FromString PyUnicode_FromString
#endif

namespace matplotlibcpp {
namespace detail {

static std::string s_backend;

struct _interpreter {
  PyObject *s_python_function_show;
  PyObject *s_python_function_close;
  PyObject *s_python_function_draw;
  PyObject *s_python_function_pause;
  PyObject *s_python_function_save;
  PyObject *s_python_function_figure;
  PyObject *s_python_function_fignum_exists;
  PyObject *s_python_function_plot;
  PyObject *s_python_function_quiver;
  PyObject *s_python_function_contour;
  PyObject *s_python_function_colormap;
  PyObject *s_python_function_axhline;
  PyObject *s_python_function_axvline;
  PyObject *s_python_function_semilogx;
  PyObject *s_python_function_semilogy;
  PyObject *s_python_function_loglog;
  PyObject *s_python_function_fill;
  PyObject *s_python_function_fill_between;
  PyObject *s_python_function_hist;
  PyObject *s_python_function_scatter;
  PyObject *s_python_function_spy;
  PyObject *s_python_function_subplot;
  PyObject *s_python_function_legend;
  PyObject *s_python_function_xlim;
  PyObject *s_python_function_ion;
  PyObject *s_python_function_ginput;
  PyObject *s_python_function_ylim;
  PyObject *s_python_function_title;
  PyObject *s_python_function_axis;
  PyObject *s_python_function_xlabel;
  PyObject *s_python_function_ylabel;
  PyObject *s_python_function_xticks;
  PyObject *s_python_function_yticks;
  PyObject *s_python_function_xscale;
  PyObject *s_python_function_yscale;
  PyObject *s_python_function_grid;
  PyObject *s_python_function_clf;
  PyObject *s_python_function_errorbar;
  PyObject *s_python_function_annotate;
  PyObject *s_python_function_tight_layout;
  PyObject *s_python_colormap;
  PyObject *s_python_empty_tuple;
  PyObject *s_python_function_stem;
  PyObject *s_python_function_xkcd;
  PyObject *s_python_function_text;
  PyObject *s_python_function_suptitle;
  PyObject *s_python_function_bar;
  PyObject *s_python_function_subplots_adjust;
  PyObject *s_python_function_imshow;
  PyObject *s_python_function_colorbar;

  /* For now, _interpreter is implemented as a singleton since its currently not
     possible to have multiple independent embedded python interpreters without
     patching the python source code or starting a separate process for each.
      http://bytes.com/topic/python/answers/793370-multiple-independent-python-interpreters-c-c-program
     */

  static _interpreter &get() {
    static _interpreter ctx;
    return ctx;
  }

private:
#ifndef WITHOUT_NUMPY
#if PY_MAJOR_VERSION >= 3

  void *import_numpy() {
    import_array(); // initialize C-API
    return NULL;
  }

#else

  void import_numpy() {
    import_array(); // initialize C-API
  }

#endif
#endif

  _interpreter() {

    // optional but recommended
#if PY_MAJOR_VERSION >= 3
    wchar_t name[] = L"plotting";
#else
    char name[] = "plotting";
#endif
    Py_SetProgramName(name);
    Py_Initialize();

#ifndef WITHOUT_NUMPY
    import_numpy(); // initialize numpy C-API
#endif

    PyObject *matplotlibname = PyString_FromString("matplotlib");
    PyObject *pyplotname = PyString_FromString("matplotlib.pyplot");
    PyObject *cmname = PyString_FromString("matplotlib.cm");
    PyObject *pylabname = PyString_FromString("pylab");
    if (!pyplotname || !pylabname || !matplotlibname || !cmname) {
      throw std::runtime_error("couldnt create string");
    }

    PyObject *matplotlib = PyImport_Import(matplotlibname);
    Py_DECREF(matplotlibname);
    if (!matplotlib) {
      PyErr_Print();
      throw std::runtime_error("Error loading module matplotlib!");
    }

    // matplotlib.use() must be called *before* pylab, matplotlib.pyplot,
    // or matplotlib.backends is imported for the first time
    if (!s_backend.empty()) {
      PyObject_CallMethod(matplotlib, const_cast<char *>("use"),
                          const_cast<char *>("s"), s_backend.c_str());
    }

    PyObject *pymod = PyImport_Import(pyplotname);
    Py_DECREF(pyplotname);
    if (!pymod) {
      throw std::runtime_error("Error loading module matplotlib.pyplot!");
    }

    s_python_colormap = PyImport_Import(cmname);
    Py_DECREF(cmname);
    if (!s_python_colormap) {
      throw std::runtime_error("Error loading module matplotlib.cm!");
    }

    PyObject *pylabmod = PyImport_Import(pylabname);
    Py_DECREF(pylabname);
    if (!pylabmod) {
      throw std::runtime_error("Error loading module pylab!");
    }

    s_python_function_show = PyObject_GetAttrString(pymod, "show");
    s_python_function_close = PyObject_GetAttrString(pymod, "close");
    s_python_function_draw = PyObject_GetAttrString(pymod, "draw");
    s_python_function_pause = PyObject_GetAttrString(pymod, "pause");
    s_python_function_figure = PyObject_GetAttrString(pymod, "figure");
    s_python_function_fignum_exists =
        PyObject_GetAttrString(pymod, "fignum_exists");
    s_python_function_plot = PyObject_GetAttrString(pymod, "plot");
    s_python_function_quiver = PyObject_GetAttrString(pymod, "quiver");
    s_python_function_contour = PyObject_GetAttrString(pymod, "contour");
    s_python_function_axhline = PyObject_GetAttrString(pymod, "axhline");
    s_python_function_axvline = PyObject_GetAttrString(pymod, "axvline");
    s_python_function_semilogx = PyObject_GetAttrString(pymod, "semilogx");
    s_python_function_semilogy = PyObject_GetAttrString(pymod, "semilogy");
    s_python_function_loglog = PyObject_GetAttrString(pymod, "loglog");
    s_python_function_fill = PyObject_GetAttrString(pymod, "fill");
    s_python_function_fill_between =
        PyObject_GetAttrString(pymod, "fill_between");
    s_python_function_hist = PyObject_GetAttrString(pymod, "hist");
    s_python_function_scatter = PyObject_GetAttrString(pymod, "scatter");
    s_python_function_spy = PyObject_GetAttrString(pymod, "spy");
    s_python_function_subplot = PyObject_GetAttrString(pymod, "subplot");
    s_python_function_legend = PyObject_GetAttrString(pymod, "legend");
    s_python_function_ylim = PyObject_GetAttrString(pymod, "ylim");
    s_python_function_title = PyObject_GetAttrString(pymod, "title");
    s_python_function_axis = PyObject_GetAttrString(pymod, "axis");
    s_python_function_xlabel = PyObject_GetAttrString(pymod, "xlabel");
    s_python_function_ylabel = PyObject_GetAttrString(pymod, "ylabel");
    s_python_function_xticks = PyObject_GetAttrString(pymod, "xticks");
    s_python_function_yticks = PyObject_GetAttrString(pymod, "yticks");
    s_python_function_xscale = PyObject_GetAttrString(pymod, "xscale");
    s_python_function_yscale = PyObject_GetAttrString(pymod, "yscale");
    s_python_function_grid = PyObject_GetAttrString(pymod, "grid");
    s_python_function_xlim = PyObject_GetAttrString(pymod, "xlim");
    s_python_function_ion = PyObject_GetAttrString(pymod, "ion");
    s_python_function_ginput = PyObject_GetAttrString(pymod, "ginput");
    s_python_function_save = PyObject_GetAttrString(pylabmod, "savefig");
    s_python_function_annotate = PyObject_GetAttrString(pymod, "annotate");
    s_python_function_clf = PyObject_GetAttrString(pymod, "clf");
    s_python_function_errorbar = PyObject_GetAttrString(pymod, "errorbar");
    s_python_function_tight_layout =
        PyObject_GetAttrString(pymod, "tight_layout");
    s_python_function_stem = PyObject_GetAttrString(pymod, "stem");
    s_python_function_xkcd = PyObject_GetAttrString(pymod, "xkcd");
    s_python_function_text = PyObject_GetAttrString(pymod, "text");
    s_python_function_suptitle = PyObject_GetAttrString(pymod, "suptitle");
    s_python_function_bar = PyObject_GetAttrString(pymod, "bar");
    s_python_function_subplots_adjust =
        PyObject_GetAttrString(pymod, "subplots_adjust");
    s_python_function_imshow = PyObject_GetAttrString(pymod, "imshow");
    s_python_function_colorbar = PyObject_GetAttrString(pymod, "colorbar");

    if (!s_python_function_show || !s_python_function_close ||
        !s_python_function_draw || !s_python_function_pause ||
        !s_python_function_figure || !s_python_function_fignum_exists ||
        !s_python_function_plot || !s_python_function_quiver ||
        !s_python_function_contour || !s_python_function_colorbar ||
        !s_python_function_semilogx || !s_python_function_semilogy ||
        !s_python_function_loglog || !s_python_function_fill ||
        !s_python_function_fill_between || !s_python_function_subplot ||
        !s_python_function_legend || !s_python_function_ylim ||
        !s_python_function_title || !s_python_function_axis ||
        !s_python_function_xlabel || !s_python_function_ylabel ||
        !s_python_function_xticks || !s_python_function_yticks ||
        !s_python_function_xscale || !s_python_function_yscale ||
        !s_python_function_grid || !s_python_function_xlim ||
        !s_python_function_ion || !s_python_function_ginput ||
        !s_python_function_save || !s_python_function_clf ||
        !s_python_function_annotate || !s_python_function_errorbar ||
        !s_python_function_errorbar || !s_python_function_tight_layout ||
        !s_python_function_stem || !s_python_function_xkcd ||
        !s_python_function_text || !s_python_function_suptitle ||
        !s_python_function_bar || !s_python_function_subplots_adjust ||
        !s_python_function_spy || !s_python_function_imshow) {
      throw std::runtime_error("Couldn't find required function!");
    }

    if (!PyFunction_Check(s_python_function_show) ||
        !PyFunction_Check(s_python_function_close) ||
        !PyFunction_Check(s_python_function_draw) ||
        !PyFunction_Check(s_python_function_pause) ||
        !PyFunction_Check(s_python_function_figure) ||
        !PyFunction_Check(s_python_function_fignum_exists) ||
        !PyFunction_Check(s_python_function_plot) ||
        !PyFunction_Check(s_python_function_quiver) ||
        !PyFunction_Check(s_python_function_contour) ||
        !PyFunction_Check(s_python_function_semilogx) ||
        !PyFunction_Check(s_python_function_semilogy) ||
        !PyFunction_Check(s_python_function_loglog) ||
        !PyFunction_Check(s_python_function_fill) ||
        !PyFunction_Check(s_python_function_fill_between) ||
        !PyFunction_Check(s_python_function_spy) ||
        !PyFunction_Check(s_python_function_subplot) ||
        !PyFunction_Check(s_python_function_legend) ||
        !PyFunction_Check(s_python_function_annotate) ||
        !PyFunction_Check(s_python_function_ylim) ||
        !PyFunction_Check(s_python_function_title) ||
        !PyFunction_Check(s_python_function_axis) ||
        !PyFunction_Check(s_python_function_xlabel) ||
        !PyFunction_Check(s_python_function_ylabel) ||
        !PyFunction_Check(s_python_function_xticks) ||
        !PyFunction_Check(s_python_function_yticks) ||
        !PyFunction_Check(s_python_function_xscale) ||
        !PyFunction_Check(s_python_function_yscale) ||
        !PyFunction_Check(s_python_function_grid) ||
        !PyFunction_Check(s_python_function_xlim) ||
        !PyFunction_Check(s_python_function_ion) ||
        !PyFunction_Check(s_python_function_ginput) ||
        !PyFunction_Check(s_python_function_save) ||
        !PyFunction_Check(s_python_function_clf) ||
        !PyFunction_Check(s_python_function_tight_layout) ||
        !PyFunction_Check(s_python_function_errorbar) ||
        !PyFunction_Check(s_python_function_stem) ||
        !PyFunction_Check(s_python_function_xkcd) ||
        !PyFunction_Check(s_python_function_text) ||
        !PyFunction_Check(s_python_function_suptitle) ||
        !PyFunction_Check(s_python_function_bar) ||
        !PyFunction_Check(s_python_function_subplots_adjust) ||
        !PyFunction_Check(s_python_function_imshow) ||
        !PyFunction_Check(s_python_function_colorbar)
      ) {
      throw std::runtime_error(
          "Python object is unexpectedly not a PyFunction.");
    }

    s_python_empty_tuple = PyTuple_New(0);
  }

  ~_interpreter() { Py_Finalize(); }
};

} // end namespace detail

// must be called before the first regular call to matplotlib to have any effect
inline void backend(const std::string &name) { detail::s_backend = name; }

inline bool annotate(std::string annotation, double x, double y,
                     const std::map<std::string, std::string> &keywords = {}) {
  detail::_interpreter::get();

  PyObject *xy = PyTuple_New(2);
  PyObject *str = PyString_FromString(annotation.c_str());

  PyTuple_SetItem(xy, 0, PyFloat_FromDouble(x));
  PyTuple_SetItem(xy, 1, PyFloat_FromDouble(y));

  PyObject *kwargs = PyDict_New();
  PyDict_SetItemString(kwargs, "xy", xy);

  for (auto const &item : keywords) {
    PyDict_SetItemString(kwargs, item.first.c_str(),
                         PyString_FromString(item.second.c_str()));
  }

  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, str);

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_annotate, args, kwargs);

  Py_DECREF(args);
  Py_DECREF(kwargs);

  if (res)
    Py_DECREF(res);

  return res;
}

#ifndef WITHOUT_NUMPY
// Type selector for numpy array conversion
template <typename T> struct select_npy_type {
  const static NPY_TYPES type = NPY_NOTYPE;
}; // Default
template <> struct select_npy_type<double> {
  const static NPY_TYPES type = NPY_DOUBLE;
};
template <> struct select_npy_type<float> {
  const static NPY_TYPES type = NPY_FLOAT;
};
template <> struct select_npy_type<bool> {
  const static NPY_TYPES type = NPY_BOOL;
};
template <> struct select_npy_type<int8_t> {
  const static NPY_TYPES type = NPY_INT8;
};
template <> struct select_npy_type<int16_t> {
  const static NPY_TYPES type = NPY_SHORT;
};
template <> struct select_npy_type<int32_t> {
  const static NPY_TYPES type = NPY_INT;
};
template <> struct select_npy_type<int64_t> {
  const static NPY_TYPES type = NPY_INT64;
};
template <> struct select_npy_type<uint8_t> {
  const static NPY_TYPES type = NPY_UINT8;
};
template <> struct select_npy_type<uint16_t> {
  const static NPY_TYPES type = NPY_USHORT;
};
template <> struct select_npy_type<uint32_t> {
  const static NPY_TYPES type = NPY_ULONG;
};
template <> struct select_npy_type<uint64_t> {
  const static NPY_TYPES type = NPY_UINT64;
};

template <typename Vector> PyObject *get_array(const Vector &v) {
  detail::_interpreter::get(); // interpreter needs to be initialized for the
                               // numpy commands to work
  // both Eigen::Matrix<..> and std::vector<..> have the member value_type
  NPY_TYPES type = select_npy_type<typename Vector::value_type>::type;
  if (type == NPY_NOTYPE) {
    std::vector<double> vd(v.size());
    npy_intp vsize = v.size();
    // Eigen Vectors do not support begin/end() in the currently stable version
    // this can be changed once Eigen 3.4. is released
    // data() returns a pointer to the storage of the first element. If the
    // vector is modified afterwards, it may be rendedered invalid.
    // Note, that this is not an issue since get_array() is called by a
    // plot command using the instantaneous state of the vector.
    // The pointer is not reused. If the vector is plotted anew, data() is
    // called again and again get's the current, valid storage location.
    std::copy(v.data(), v.data() + v.size(), vd.begin());
    PyObject *varray =
        PyArray_SimpleNewFromData(1, &vsize, NPY_DOUBLE, (void *)(vd.data()));
    return varray;
  }

  npy_intp vsize = v.size();
  PyObject *varray =
      PyArray_SimpleNewFromData(1, &vsize, type, (void *)(v.data()));
  return varray;
}

// specialized get_2darray function for nested std::vectors
template <typename Numeric>
PyObject *get_2darray(const std::vector<::std::vector<Numeric>> &v) {
  detail::_interpreter::get(); // interpreter needs to be initialized for the
                               // numpy commands to work
  if (v.size() < 1)
    throw std::runtime_error("get_2darray v too small");

  npy_intp vsize[2] = {static_cast<npy_intp>(v.size()),
                       static_cast<npy_intp>(v[0].size())};

  PyArrayObject *varray =
      (PyArrayObject *)PyArray_SimpleNew(2, vsize, NPY_DOUBLE);

  double *vd_begin = static_cast<double *>(PyArray_DATA(varray));

  for (const ::std::vector<Numeric> &v_row : v) {
    if (v_row.size() != static_cast<size_t>(vsize[1]))
      throw std::runtime_error("mismatched array size");
    std::copy(v_row.begin(), v_row.end(), vd_begin);
    vd_begin += vsize[1];
  }

  return reinterpret_cast<PyObject *>(varray);
}

// suitable for more general matrices (especially Eigen matrices)
template <typename Matrix> PyObject *get_2darray(const Matrix &A) {
  detail::_interpreter::get(); // interpreter needs to be initialized for the
                               // numpy commands to work
  if (A.size() < 1)
    throw std::runtime_error("get_2darray A too small");

  npy_intp vsize[2] = {static_cast<npy_intp>(A.rows()),
                       static_cast<npy_intp>(A.cols())};

  PyArrayObject *varray =
      (PyArrayObject *)PyArray_SimpleNew(2, vsize, NPY_DOUBLE);

  double *vd_begin = static_cast<double *>(PyArray_DATA(varray));

  for (std::size_t i = 0; i < A.rows(); ++i) {
    for (std::size_t j = 0; j < A.cols(); ++j) {
      *(vd_begin + i * A.cols() + j) = A(i, j);
    }
  }

  return reinterpret_cast<PyObject *>(varray);
}

#else // fallback if we don't have numpy: copy every element of the given vector

template <typename Vector> PyObject *get_array(const Vector &v) {
  detail::_interpreter::get();
  PyObject *list = PyList_New(v.size());
  for (size_t i = 0; i < v.size(); ++i) {
    PyList_SetItem(list, i, PyFloat_FromDouble(v.at(i)));
  }
  return list;
}

#endif // WITHOUT_NUMPY

namespace detail {
// @brief Since most of the plot commands require the exact same usage apart
//        from the call to the correct Python function, we encapsulate this
// @param pyfunc The matplotlib function to be called with the given arguments
// @param x The x vector
// @param y The y vector
// @param s The formatting string for colour, marker and linestyle
// @param keywords Additional keywords, such as label
// @return true if plot was successful, false otherwise
template <typename VectorX, typename VectorY>
bool plot_base(PyObject *const pyfunc, const VectorX &x, const VectorY &y,
               const std::string &s = "",
               const std::map<std::string, std::string> &keywords = {}) {
  assert(x.size() == y.size());

  PyObject *xarray = get_array(x);
  PyObject *yarray = get_array(y);

  PyObject *pystring = PyString_FromString(s.c_str());

  PyObject *plot_args = PyTuple_New(3);
  PyTuple_SetItem(plot_args, 0, xarray);
  PyTuple_SetItem(plot_args, 1, yarray);
  PyTuple_SetItem(plot_args, 2, pystring);

  PyObject *kwargs = PyDict_New();
  for (auto const &item : keywords) {
    PyDict_SetItemString(kwargs, item.first.c_str(),
                         PyString_FromString(item.second.c_str()));
  }

  PyObject *res = PyObject_Call(pyfunc, plot_args, kwargs);

  Py_DECREF(plot_args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);

  return res;
}

} // namespace detail

// @brief standard plot function supporting the args (x, y, s, keywords)
// @param x The x vector
// @param y The y vector
// @param s The formatting string
// @param keywords Additional keywords
// @return true, if successful, false otherwise
template <typename VectorX, typename VectorY>
bool plot(const VectorX &x, const VectorY &y, const std::string &s = "",
          const std::map<std::string, std::string> &keywords = {}) {
  return detail::plot_base(detail::_interpreter::get().s_python_function_plot,
                           x, y, s, keywords);
}

// @brief standard plot function without formatting string, needed if
//        keywords are given but formatting string is not
template <typename VectorX, typename VectorY>
bool plot(const VectorX &x, const VectorY &y,
          const std::map<std::string, std::string> &keywords) {
  return plot(x, y, "", keywords);
}

// @brief standard plot function if x data is not specified
template <typename VectorY = std::vector<double>>
bool plot(const VectorY &y, const std::string &format = "",
          const std::map<std::string, std::string> &keywords = {}) {
  // Note: cannot be an unsigned type for some reason, yields an overflow
  // problem..
  std::vector<int> x(y.size());
  for (int i = 0; i < x.size(); ++i)
    x.at(i) = i;

  return plot(x, y, format);
}

// @brief standard plot function if x data is not specified and the formatting
//        string is missing
template <typename VectorY = std::vector<double>>
bool plot(const VectorY &y,
          const std::map<std::string, std::string> &keywords) {
  std::vector<int> x(y.size());
  for (int i = 0; i < x.size(); ++i)
    x.at(i) = i;

  return plot(x, y, "", keywords);
}

// @brief loglog plot function, see `plot` for more detail
template <typename VectorX, typename VectorY>
bool loglog(const VectorX &x, const VectorY &y, const std::string &s = "",
            const std::map<std::string, std::string> &keywords = {}) {
  return detail::plot_base(detail::_interpreter::get().s_python_function_loglog,
                           x, y, s, keywords);
}

template <typename VectorX, typename VectorY>
bool loglog(const VectorX &x, const VectorY &y,
            const std::map<std::string, std::string> &keywords) {
  return loglog(x, y, "", keywords);
}

template <typename VectorY = std::vector<double>>
bool loglog(const VectorY &y, const std::string &s = "",
            const std::map<std::string, std::string> &keywords = {}) {
  std::vector<std::size_t> x(y.size());
  for (std::size_t i = 0; i < x.size(); ++i)
    x.at(i) = i;

  return loglog(x, y, s, keywords);
}

template <typename VectorY = std::vector<double>>
bool loglog(const VectorY &y,
            const std::map<std::string, std::string> &keywords) {
  std::vector<std::size_t> x(y.size());
  for (std::size_t i = 0; i < x.size(); ++i)
    x.at(i) = i;

  return loglog(x, y, "", keywords);
}

// @brief semilogx plot function, see `plot` for more detail
template <typename VectorX, typename VectorY>
bool semilogx(const VectorX &x, const VectorY &y, const std::string &s = "",
              const std::map<std::string, std::string> &keywords = {}) {
  return detail::plot_base(
      detail::_interpreter::get().s_python_function_semilogx, x, y, s,
      keywords);
}

template <typename VectorX, typename VectorY>
bool semilogx(const VectorX &x, const VectorY &y,
              const std::map<std::string, std::string> &keywords) {
  return semilogx(x, y, "", keywords);
}

template <typename VectorY = std::vector<double>>
bool semilogx(const VectorY &y, const std::string &s = "",
              const std::map<std::string, std::string> &keywords = {}) {
  std::vector<std::size_t> x(y.size());
  for (std::size_t i = 0; i < x.size(); ++i)
    x.at(i) = i;

  return semilogx(x, y, s, keywords);
}

template <typename VectorY = std::vector<double>>
bool semilogx(const VectorY &y,
              const std::map<std::string, std::string> &keywords) {
  std::vector<std::size_t> x(y.size());
  for (std::size_t i = 0; i < x.size(); ++i)
    x.at(i) = i;

  return semilogx(x, y, "", keywords);
}

// @brief semilogy plot function, see `plot` for more detail
template <typename VectorX, typename VectorY>
bool semilogy(const VectorX &x, const VectorY &y, const std::string &s = "",
              const std::map<std::string, std::string> &keywords = {}) {
  return detail::plot_base(
      detail::_interpreter::get().s_python_function_semilogy, x, y, s,
      keywords);
}

template <typename VectorX, typename VectorY>
bool semilogy(const VectorX &x, const VectorY &y,
              const std::map<std::string, std::string> &keywords) {
  return semilogy(x, y, "", keywords);
}

template <typename VectorY = std::vector<double>>
bool semilogy(const VectorY &y, const std::string &s = "",
              const std::map<std::string, std::string> &keywords = {}) {
  std::vector<std::size_t> x(y.size());
  for (std::size_t i = 0; i < x.size(); ++i)
    x.at(i) = i;

  return semilogy(x, y, s, keywords);
}

template <typename VectorY = std::vector<double>>
bool semilogy(const VectorY &y,
              const std::map<std::string, std::string> &keywords) {
  std::vector<std::size_t> x(y.size());
  for (std::size_t i = 0; i < x.size(); ++i)
    x.at(i) = i;

  return semilogy(x, y, "", keywords);
}

template <typename Matrix>
void imshow(const Matrix& X, const std::map<std::string, std::string> &keywords = {}) {
  PyObject *Xarray = get_2darray(X);

  PyObject *kwargs = PyDict_New();
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *plot_args = PyTuple_New(1);
  PyTuple_SetItem(plot_args, 0, Xarray);

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_imshow, plot_args, kwargs);

  Py_DECREF(plot_args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);
}

// @brief Add the colorbar
void colorbar() {
  PyObject *res =
      PyObject_CallObject(detail::_interpreter::get().s_python_function_colorbar,
                          detail::_interpreter::get().s_python_empty_tuple);
  if (!res)
    throw std::runtime_error("Call to colorbar() failed.");
}

// @brief plot_surface for datapoints (x_ij, y_ij, z_ij) with i,j = 0..n
// @param x The x values of the datapoints in a matrix
// @param y The y values of the datapoints in a matrix
// @param z The function value of the datapoints in a matrix
// @param keywords Additional keywords
template <typename Matrix>
void plot_surface(const Matrix &x, const Matrix &y, const Matrix &z,
                  const std::map<std::string, std::string> &keywords =
                      std::map<std::string, std::string>()) {
  // We lazily load the modules here the first time this function is called
  // because I'm not sure that we can assume "matplotlib installed" implies
  // "mpl_toolkits installed" on all platforms, and we don't want to require
  // it for people who don't need 3d plots.
  static PyObject *mpl_toolkitsmod = nullptr, *axis3dmod = nullptr;
  if (!mpl_toolkitsmod) {
    detail::_interpreter::get();

    PyObject *mpl_toolkits = PyString_FromString("mpl_toolkits");
    PyObject *axis3d = PyString_FromString("mpl_toolkits.mplot3d");
    if (!mpl_toolkits || !axis3d) {
      throw std::runtime_error("couldnt create string");
    }

    mpl_toolkitsmod = PyImport_Import(mpl_toolkits);
    Py_DECREF(mpl_toolkits);
    if (!mpl_toolkitsmod) {
      throw std::runtime_error("Error loading module mpl_toolkits!");
    }

    axis3dmod = PyImport_Import(axis3d);
    Py_DECREF(axis3d);
    if (!axis3dmod) {
      throw std::runtime_error("Error loading module mpl_toolkits.mplot3d!");
    }
  }

  assert(x.size() == y.size());
  assert(y.size() == z.size());

  // using numpy arrays
  PyObject *xarray = get_2darray(x);
  PyObject *yarray = get_2darray(y);
  PyObject *zarray = get_2darray(z);

  // construct positional args
  PyObject *args = PyTuple_New(3);
  PyTuple_SetItem(args, 0, xarray);
  PyTuple_SetItem(args, 1, yarray);
  PyTuple_SetItem(args, 2, zarray);

  // Build up the kw args.
  PyObject *kwargs = PyDict_New();
  PyDict_SetItemString(kwargs, "rstride", PyInt_FromLong(1));
  PyDict_SetItemString(kwargs, "cstride", PyInt_FromLong(1));

  PyObject *python_colormap_coolwarm = PyObject_GetAttrString(
      detail::_interpreter::get().s_python_colormap, "coolwarm");

  PyDict_SetItemString(kwargs, "cmap", python_colormap_coolwarm);

  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyString_FromString(it->second.c_str()));
  }

  PyObject *fig =
      PyObject_CallObject(detail::_interpreter::get().s_python_function_figure,
                          detail::_interpreter::get().s_python_empty_tuple);
  if (!fig)
    throw std::runtime_error("Call to figure() failed.");

  PyObject *gca_kwargs = PyDict_New();
  PyDict_SetItemString(gca_kwargs, "projection", PyString_FromString("3d"));

  PyObject *gca = PyObject_GetAttrString(fig, "gca");
  if (!gca)
    throw std::runtime_error("No gca");
  Py_INCREF(gca);
  PyObject *axis = PyObject_Call(
      gca, detail::_interpreter::get().s_python_empty_tuple, gca_kwargs);

  if (!axis)
    throw std::runtime_error("No axis");
  Py_INCREF(axis);

  Py_DECREF(gca);
  Py_DECREF(gca_kwargs);

  PyObject *plot_surface = PyObject_GetAttrString(axis, "plot_surface");
  if (!plot_surface)
    throw std::runtime_error("No surface");
  Py_INCREF(plot_surface);
  PyObject *res = PyObject_Call(plot_surface, args, kwargs);
  if (!res)
    throw std::runtime_error("failed surface");
  Py_DECREF(plot_surface);

  Py_DECREF(axis);
  Py_DECREF(args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);
}

// @brief plot_surface for datapoints (x_ij, y_ij, z_ij) with i,j = 0..n
// @param x The x values of the datapoints in a matrix
// @param y The y values of the datapoints in a matrix
// @param z The function value of the datapoints in a matrix
// @param keywords Additional keywords
template <typename Matrix>
void contour(const Matrix &x, const Matrix &y, const Matrix &z,
             const std::map<std::string, std::string> &keywords = {}) {
  detail::_interpreter::get();

  // using numpy arrays
  PyObject *xarray = get_2darray(x);
  PyObject *yarray = get_2darray(y);
  PyObject *zarray = get_2darray(z);

  // construct positional args
  PyObject *args = PyTuple_New(3);
  PyTuple_SetItem(args, 0, xarray);
  PyTuple_SetItem(args, 1, yarray);
  PyTuple_SetItem(args, 2, zarray);

  // Build up the kw args.
  PyObject *kwargs = PyDict_New();

  PyObject *python_colormap_coolwarm = PyObject_GetAttrString(
      detail::_interpreter::get().s_python_colormap, "coolwarm");

  PyDict_SetItemString(kwargs, "cmap", python_colormap_coolwarm);

  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyString_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_contour, args, kwargs);
  if (!res)
    throw std::runtime_error("failed surface");

  Py_DECREF(args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);
}

template <typename Numeric>
bool stem(const std::vector<Numeric> &x, const std::vector<Numeric> &y,
          const std::map<std::string, std::string> &keywords) {
  assert(x.size() == y.size());

  // using numpy arrays
  PyObject *xarray = get_array(x);
  PyObject *yarray = get_array(y);

  // construct positional args
  PyObject *args = PyTuple_New(2);
  PyTuple_SetItem(args, 0, xarray);
  PyTuple_SetItem(args, 1, yarray);

  // construct keyword args
  PyObject *kwargs = PyDict_New();
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyString_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_stem, args, kwargs);

  Py_DECREF(args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);

  return res;
}

template <typename Numeric>
bool fill(const std::vector<Numeric> &x, const std::vector<Numeric> &y,
          const std::map<std::string, std::string> &keywords) {
  assert(x.size() == y.size());

  // using numpy arrays
  PyObject *xarray = get_array(x);
  PyObject *yarray = get_array(y);

  // construct positional args
  PyObject *args = PyTuple_New(2);
  PyTuple_SetItem(args, 0, xarray);
  PyTuple_SetItem(args, 1, yarray);

  // construct keyword args
  PyObject *kwargs = PyDict_New();
  for (auto it = keywords.begin(); it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_fill, args, kwargs);

  Py_DECREF(args);
  Py_DECREF(kwargs);

  if (res)
    Py_DECREF(res);

  return res;
}

template <typename Numeric>
bool fill_between(const std::vector<Numeric> &x, const std::vector<Numeric> &y1,
                  const std::vector<Numeric> &y2,
                  const std::map<std::string, std::string> &keywords) {
  assert(x.size() == y1.size());
  assert(x.size() == y2.size());

  // using numpy arrays
  PyObject *xarray = get_array(x);
  PyObject *y1array = get_array(y1);
  PyObject *y2array = get_array(y2);

  // construct positional args
  PyObject *args = PyTuple_New(3);
  PyTuple_SetItem(args, 0, xarray);
  PyTuple_SetItem(args, 1, y1array);
  PyTuple_SetItem(args, 2, y2array);

  // construct keyword args
  PyObject *kwargs = PyDict_New();
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_fill_between, args, kwargs);

  Py_DECREF(args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);

  return res;
}

template <typename VectorY>
bool hist(const VectorY &y, long bins = 10, std::string color = "b",
          double alpha = 1.0, bool cumulative = false) {

  PyObject *yarray = get_array(y);

  PyObject *kwargs = PyDict_New();
  PyDict_SetItemString(kwargs, "bins", PyLong_FromLong(bins));
  PyDict_SetItemString(kwargs, "color", PyString_FromString(color.c_str()));
  PyDict_SetItemString(kwargs, "alpha", PyFloat_FromDouble(alpha));
  PyDict_SetItemString(kwargs, "cumulative", cumulative ? Py_True : Py_False);

  PyObject *plot_args = PyTuple_New(1);

  PyTuple_SetItem(plot_args, 0, yarray);

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_hist, plot_args, kwargs);

  Py_DECREF(plot_args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);

  return res;
}

// @brief Scatter plot
// @param x x-coordinates of the 2d points
// @param y y-coordinates of the 2d points
// @param s the marker size in points**2
// @param keywords Additional keywords
template <typename VectorX, typename VectorY>
bool scatter(const VectorX &x, const VectorY &y, const double s = 1.0,
             const std::map<std::string, std::string> keywords = {}) {
  assert(x.size() == y.size());

  PyObject *xarray = get_array(x);
  PyObject *yarray = get_array(y);

  PyObject *kwargs = PyDict_New();
  PyDict_SetItemString(kwargs, "s", PyFloat_FromDouble(s));
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *plot_args = PyTuple_New(2);
  PyTuple_SetItem(plot_args, 0, xarray);
  PyTuple_SetItem(plot_args, 1, yarray);

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_scatter, plot_args, kwargs);

  Py_DECREF(plot_args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);

  return res;
}

template <typename VectorX, typename VectorY>
bool scatter(const VectorX &x, const VectorY &y,
             const std::map<std::string, std::string> &keywords) {
  return scatter(x, y, 1.0, keywords);
}

// @brief Spy plot
// @param A the matrix
// @param precision Plot all elements above `|precision|`
// @param keywords Additional keywords
template <typename Matrix>
bool spy(const Matrix &A,
         const std::map<std::string, std::string> &keywords = {}) {
  PyObject *Aarray = get_2darray(A);

  PyObject *kwargs = PyDict_New();
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *plot_args = PyTuple_New(1);
  PyTuple_SetItem(plot_args, 0, Aarray);

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_spy, plot_args, kwargs);

  Py_DECREF(plot_args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);

  return res;
}

template <typename Numeric>
bool bar(const std::vector<Numeric> &y, std::string ec = "black",
         std::string ls = "-", double lw = 1.0,
         const std::map<std::string, std::string> &keywords = {}) {
  PyObject *yarray = get_array(y);

  std::vector<int> x;
  for (int i = 0; i < y.size(); i++)
    x.push_back(i);

  PyObject *xarray = get_array(x);

  PyObject *kwargs = PyDict_New();

  PyDict_SetItemString(kwargs, "ec", PyString_FromString(ec.c_str()));
  PyDict_SetItemString(kwargs, "ls", PyString_FromString(ls.c_str()));
  PyDict_SetItemString(kwargs, "lw", PyFloat_FromDouble(lw));

  PyObject *plot_args = PyTuple_New(2);
  PyTuple_SetItem(plot_args, 0, xarray);
  PyTuple_SetItem(plot_args, 1, yarray);

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_bar, plot_args, kwargs);

  Py_DECREF(plot_args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);

  return res;
}

inline bool
subplots_adjust(const std::map<std::string, double> &keywords = {}) {

  PyObject *kwargs = PyDict_New();
  for (std::map<std::string, double>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyFloat_FromDouble(it->second));
  }

  PyObject *plot_args = PyTuple_New(0);

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_subplots_adjust, plot_args,
      kwargs);

  Py_DECREF(plot_args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);

  return res;
}

template <typename Numeric>
bool named_hist(std::string label, const std::vector<Numeric> &y,
                long bins = 10, std::string color = "b", double alpha = 1.0) {
  PyObject *yarray = get_array(y);

  PyObject *kwargs = PyDict_New();
  PyDict_SetItemString(kwargs, "label", PyString_FromString(label.c_str()));
  PyDict_SetItemString(kwargs, "bins", PyLong_FromLong(bins));
  PyDict_SetItemString(kwargs, "color", PyString_FromString(color.c_str()));
  PyDict_SetItemString(kwargs, "alpha", PyFloat_FromDouble(alpha));

  PyObject *plot_args = PyTuple_New(1);
  PyTuple_SetItem(plot_args, 0, yarray);

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_hist, plot_args, kwargs);

  Py_DECREF(plot_args);
  Py_DECREF(kwargs);
  if (res)
    Py_DECREF(res);

  return res;
}

template <typename NumericX, typename NumericY, typename NumericU,
          typename NumericW>
bool quiver(const std::vector<NumericX> &x, const std::vector<NumericY> &y,
            const std::vector<NumericU> &u, const std::vector<NumericW> &w,
            const std::map<std::string, std::string> &keywords = {}) {
  assert(x.size() == y.size() && x.size() == u.size() && u.size() == w.size());

  PyObject *xarray = get_array(x);
  PyObject *yarray = get_array(y);
  PyObject *uarray = get_array(u);
  PyObject *warray = get_array(w);

  PyObject *plot_args = PyTuple_New(4);
  PyTuple_SetItem(plot_args, 0, xarray);
  PyTuple_SetItem(plot_args, 1, yarray);
  PyTuple_SetItem(plot_args, 2, uarray);
  PyTuple_SetItem(plot_args, 3, warray);

  // construct keyword args
  PyObject *kwargs = PyDict_New();
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_quiver, plot_args, kwargs);

  Py_DECREF(kwargs);
  Py_DECREF(plot_args);
  if (res)
    Py_DECREF(res);

  return res;
}

template <typename NumericY>
void axhline(const NumericY y,
             const std::map<std::string, std::string> keywords = {}) {
  detail::_interpreter::get();

  PyObject *kwargs = PyDict_New();

  // add location
  PyDict_SetItemString(kwargs, "y", PyFloat_FromDouble(y));

  // add other keywords
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *res =
      PyObject_Call(detail::_interpreter::get().s_python_function_axhline,
                    detail::_interpreter::get().s_python_empty_tuple, kwargs);

  Py_DECREF(kwargs);

  if (!res)
    throw std::runtime_error("Call to axhline() failed.");

  Py_DECREF(res);
}

template <typename NumericX>
void axvline(const NumericX x,
             const std::map<std::string, std::string> keywords = {}) {
  detail::_interpreter::get();

  PyObject *kwargs = PyDict_New();

  // add location
  PyDict_SetItemString(kwargs, "x", PyFloat_FromDouble(x));

  // add other keywords
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *res =
      PyObject_Call(detail::_interpreter::get().s_python_function_axvline,
                    detail::_interpreter::get().s_python_empty_tuple, kwargs);

  Py_DECREF(kwargs);

  if (!res)
    throw std::runtime_error("Call to axvline() failed.");

  Py_DECREF(res);
}

template <typename NumericX, typename NumericY>
bool stem(const std::vector<NumericX> &x, const std::vector<NumericY> &y,
          const std::string &s = "") {
  assert(x.size() == y.size());

  PyObject *xarray = get_array(x);
  PyObject *yarray = get_array(y);

  PyObject *pystring = PyString_FromString(s.c_str());

  PyObject *plot_args = PyTuple_New(3);
  PyTuple_SetItem(plot_args, 0, xarray);
  PyTuple_SetItem(plot_args, 1, yarray);
  PyTuple_SetItem(plot_args, 2, pystring);

  PyObject *res = PyObject_CallObject(
      detail::_interpreter::get().s_python_function_stem, plot_args);

  Py_DECREF(plot_args);
  if (res)
    Py_DECREF(res);

  return res;
}

template <typename VectorX, typename VectorY>
bool errorbar(const VectorX &x, const VectorY &y, const VectorY &yerr,
              const std::map<std::string, std::string> &keywords = {}) {
  assert(x.size() == y.size());

  PyObject *xarray = get_array(x);
  PyObject *yarray = get_array(y);
  PyObject *yerrarray = get_array(yerr);

  // construct keyword args
  PyObject *kwargs = PyDict_New();
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyString_FromString(it->second.c_str()));
  }

  PyDict_SetItemString(kwargs, "yerr", yerrarray);

  PyObject *plot_args = PyTuple_New(2);
  PyTuple_SetItem(plot_args, 0, xarray);
  PyTuple_SetItem(plot_args, 1, yarray);

  PyObject *res =
      PyObject_Call(detail::_interpreter::get().s_python_function_errorbar,
                    plot_args, kwargs);

  Py_DECREF(kwargs);
  Py_DECREF(plot_args);

  if (res)
    Py_DECREF(res);
  else
    throw std::runtime_error("Call to errorbar() failed.");

  return res;
}

template <typename Numeric>
bool stem(const std::vector<Numeric> &y, const std::string &format = "") {
  std::vector<Numeric> x(y.size());
  for (size_t i = 0; i < x.size(); ++i)
    x.at(i) = i;
  return stem(x, y, format);
}

template <typename Numeric>
void text(Numeric x, Numeric y, const std::string &s = "",
          const std::map<std::string, std::string> &keywords = {}) {
  detail::_interpreter::get();

  PyObject *args = PyTuple_New(3);
  PyTuple_SetItem(args, 0, PyFloat_FromDouble(x));
  PyTuple_SetItem(args, 1, PyFloat_FromDouble(y));
  PyTuple_SetItem(args, 2, PyString_FromString(s.c_str()));

  PyObject *kwargs = PyDict_New();
  for (auto const &item : keywords) {
    PyDict_SetItemString(kwargs, item.first.c_str(),
                         PyString_FromString(item.second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_text, args, kwargs);
  if (!res)
    throw std::runtime_error("Call to text() failed.");

  Py_DECREF(args);
  Py_DECREF(res);
}

inline long figure(long number = -1) {
  PyObject *res;
  if (number == -1)
    res = PyObject_CallObject(
        detail::_interpreter::get().s_python_function_figure,
        detail::_interpreter::get().s_python_empty_tuple);
  else {
    assert(number > 0);

    // Make sure interpreter is initialised
    detail::_interpreter::get();

    PyObject *args = PyTuple_New(1);
    PyTuple_SetItem(args, 0, PyLong_FromLong(number));
    res = PyObject_CallObject(
        detail::_interpreter::get().s_python_function_figure, args);
    Py_DECREF(args);
  }

  if (!res)
    throw std::runtime_error("Call to figure() failed.");

  PyObject *num = PyObject_GetAttrString(res, "number");
  if (!num)
    throw std::runtime_error("Could not get number attribute of figure object");
  const long figureNumber = PyLong_AsLong(num);

  Py_DECREF(num);
  Py_DECREF(res);

  return figureNumber;
}

inline bool fignum_exists(long number) {
  // Make sure interpreter is initialised
  detail::_interpreter::get();

  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, PyLong_FromLong(number));
  PyObject *res = PyObject_CallObject(
      detail::_interpreter::get().s_python_function_fignum_exists, args);
  if (!res)
    throw std::runtime_error("Call to fignum_exists() failed.");

  bool ret = PyObject_IsTrue(res);
  Py_DECREF(res);
  Py_DECREF(args);

  return ret;
}

inline void figure_size(size_t w, size_t h) {
  // Make sure interpreter is initialised
  detail::_interpreter::get();

  const size_t dpi = 100;
  PyObject *size = PyTuple_New(2);
  PyTuple_SetItem(size, 0, PyFloat_FromDouble((double)w / dpi));
  PyTuple_SetItem(size, 1, PyFloat_FromDouble((double)h / dpi));

  PyObject *kwargs = PyDict_New();
  PyDict_SetItemString(kwargs, "figsize", size);
  PyDict_SetItemString(kwargs, "dpi", PyLong_FromSize_t(dpi));

  PyObject *res =
      PyObject_Call(detail::_interpreter::get().s_python_function_figure,
                    detail::_interpreter::get().s_python_empty_tuple, kwargs);

  Py_DECREF(kwargs);

  if (!res)
    throw std::runtime_error("Call to figure_size() failed.");
  Py_DECREF(res);
}

template <typename Vector = std::vector<double>>
inline void legend(const std::string &loc = "best",
                   const Vector &bbox_to_anchor = Vector(),
                   const std::map<std::string, std::string> &keywords = {}) {
  detail::_interpreter::get();

  PyObject *kwargs = PyDict_New();

  // add location
  if (loc != "")
    PyDict_SetItemString(kwargs, "loc", PyString_FromString(loc.c_str()));

  // add bbox to anchor
  if (bbox_to_anchor.size() == 2 || bbox_to_anchor.size() == 4) {
    PyObject *bbox = get_array(bbox_to_anchor);
    PyDict_SetItemString(kwargs, "bbox_to_anchor", bbox);
  }

  // add other keywords
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyString_FromString(it->second.c_str()));
  }

  PyObject *res =
      PyObject_Call(detail::_interpreter::get().s_python_function_legend,
                    detail::_interpreter::get().s_python_empty_tuple, kwargs);

  Py_DECREF(kwargs);

  if (!res)
    throw std::runtime_error("Call to legend() failed.");

  Py_DECREF(res);
}

template <typename Vector>
inline void legend(const Vector &bbox_to_anchor,
                   const std::map<std::string, std::string> &keywords = {}) {
  legend("", bbox_to_anchor, keywords);
}

inline void legend(const std::string &loc,
                   const std::map<std::string, std::string> &keywords = {}) {
  legend(loc, std::vector<double>(), keywords);
}

// to support C-style strings we also need const char[], std::string only
// does not capture calls of style legend("lower left")
inline void legend(const char loc[],
                   const std::map<std::string, std::string> &keywords = {}) {
  legend(loc, std::vector<double>(), keywords);
}

/*
inline void legend(const std::string& loc,
                   const std::map<std::string, std::string>& keywords = {}) {
  legend(loc, std::vector<double>(), keywords);
}

inline void legend(const std::map<std::string, std::string>& keywords) {
  legend("", std::vector<double>(), keywords);
}
*/

template <typename Numeric> void ylim(const Numeric bottom, const Numeric top) {
  detail::_interpreter::get();

  PyObject *list = PyList_New(2);
  PyList_SetItem(list, 0, PyFloat_FromDouble(bottom));
  PyList_SetItem(list, 1, PyFloat_FromDouble(top));

  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, list);

  PyObject *res = PyObject_CallObject(
      detail::_interpreter::get().s_python_function_ylim, args);
  if (!res)
    throw std::runtime_error("Call to ylim() failed.");

  Py_DECREF(args);
  Py_DECREF(res);
}

template <typename Numeric> void xlim(const Numeric left, const Numeric right) {
  detail::_interpreter::get();

  PyObject *list = PyList_New(2);
  PyList_SetItem(list, 0, PyFloat_FromDouble(left));
  PyList_SetItem(list, 1, PyFloat_FromDouble(right));

  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, list);

  PyObject *res = PyObject_CallObject(
      detail::_interpreter::get().s_python_function_xlim, args);
  if (!res)
    throw std::runtime_error("Call to xlim() failed.");

  Py_DECREF(args);
  Py_DECREF(res);
}

inline double *xlim() {
  detail::_interpreter::get();

  PyObject *args = PyTuple_New(0);
  PyObject *res = PyObject_CallObject(
      detail::_interpreter::get().s_python_function_xlim, args);
  PyObject *left = PyTuple_GetItem(res, 0);
  PyObject *right = PyTuple_GetItem(res, 1);

  double *arr = new double[2];
  arr[0] = PyFloat_AsDouble(left);
  arr[1] = PyFloat_AsDouble(right);

  if (!res)
    throw std::runtime_error("Call to xlim() failed.");

  Py_DECREF(res);
  return arr;
}

inline double *ylim() {
  detail::_interpreter::get();

  PyObject *args = PyTuple_New(0);
  PyObject *res = PyObject_CallObject(
      detail::_interpreter::get().s_python_function_ylim, args);
  PyObject *bottom = PyTuple_GetItem(res, 0);
  PyObject *top = PyTuple_GetItem(res, 1);

  double *arr = new double[2];
  arr[0] = PyFloat_AsDouble(bottom);
  arr[1] = PyFloat_AsDouble(top);

  if (!res)
    throw std::runtime_error("Call to ylim() failed.");

  Py_DECREF(res);
  return arr;
}

template <typename Numeric>
inline void xticks(const std::vector<Numeric> &ticks,
                   const std::vector<std::string> &labels = {},
                   const std::map<std::string, std::string> &keywords = {}) {
  assert(labels.size() == 0 || ticks.size() == labels.size());

  // using numpy array
  PyObject *ticksarray = get_array(ticks);

  PyObject *args;
  if (labels.size() == 0) {
    // construct positional args
    args = PyTuple_New(1);
    PyTuple_SetItem(args, 0, ticksarray);
  } else {
    // make tuple of tick labels
    PyObject *labelstuple = PyTuple_New(labels.size());
    for (size_t i = 0; i < labels.size(); i++)
      PyTuple_SetItem(labelstuple, i, PyUnicode_FromString(labels[i].c_str()));

    // construct positional args
    args = PyTuple_New(2);
    PyTuple_SetItem(args, 0, ticksarray);
    PyTuple_SetItem(args, 1, labelstuple);
  }

  // construct keyword args
  PyObject *kwargs = PyDict_New();
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyString_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_xticks, args, kwargs);

  Py_DECREF(args);
  Py_DECREF(kwargs);
  if (!res)
    throw std::runtime_error("Call to xticks() failed");

  Py_DECREF(res);
}

template <typename Numeric>
inline void xticks(const std::vector<Numeric> &ticks,
                   const std::map<std::string, std::string> &keywords) {
  xticks(ticks, {}, keywords);
}

template <typename Numeric>
inline void yticks(const std::vector<Numeric> &ticks,
                   const std::vector<std::string> &labels = {},
                   const std::map<std::string, std::string> &keywords = {}) {
  assert(labels.size() == 0 || ticks.size() == labels.size());

  // using numpy array
  PyObject *ticksarray = get_array(ticks);

  PyObject *args;
  if (labels.size() == 0) {
    // construct positional args
    args = PyTuple_New(1);
    PyTuple_SetItem(args, 0, ticksarray);
  } else {
    // make tuple of tick labels
    PyObject *labelstuple = PyTuple_New(labels.size());
    for (size_t i = 0; i < labels.size(); i++)
      PyTuple_SetItem(labelstuple, i, PyUnicode_FromString(labels[i].c_str()));

    // construct positional args
    args = PyTuple_New(2);
    PyTuple_SetItem(args, 0, ticksarray);
    PyTuple_SetItem(args, 1, labelstuple);
  }

  // construct keyword args
  PyObject *kwargs = PyDict_New();
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyString_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_yticks, args, kwargs);

  Py_DECREF(args);
  Py_DECREF(kwargs);
  if (!res)
    throw std::runtime_error("Call to yticks() failed");

  Py_DECREF(res);
}

template <typename Numeric>
inline void yticks(const std::vector<Numeric> &ticks,
                   const std::map<std::string, std::string> &keywords) {
  yticks(ticks, {}, keywords);
}

inline void subplot(long nrows, long ncols, long plot_number) {
  detail::_interpreter::get();

  // construct positional args
  PyObject *args = PyTuple_New(3);
  PyTuple_SetItem(args, 0, PyFloat_FromDouble(nrows));
  PyTuple_SetItem(args, 1, PyFloat_FromDouble(ncols));
  PyTuple_SetItem(args, 2, PyFloat_FromDouble(plot_number));

  PyObject *res = PyObject_CallObject(
      detail::_interpreter::get().s_python_function_subplot, args);
  if (!res)
    throw std::runtime_error("Call to subplot() failed.");

  Py_DECREF(args);
  Py_DECREF(res);
}

inline void title(const std::string &titlestr,
                  const std::map<std::string, std::string> &keywords = {}) {
  detail::_interpreter::get();

  PyObject *pytitlestr = PyString_FromString(titlestr.c_str());
  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, pytitlestr);

  PyObject *kwargs = PyDict_New();
  for (auto it = keywords.begin(); it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_title, args, kwargs);
  if (!res)
    throw std::runtime_error("Call to title() failed.");

  Py_DECREF(args);
  Py_DECREF(kwargs);
  Py_DECREF(res);
}

inline void suptitle(const std::string &suptitlestr,
                     const std::map<std::string, std::string> &keywords = {}) {
  detail::_interpreter::get();

  PyObject *pysuptitlestr = PyString_FromString(suptitlestr.c_str());
  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, pysuptitlestr);

  PyObject *kwargs = PyDict_New();
  for (auto it = keywords.begin(); it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_suptitle, args, kwargs);
  if (!res)
    throw std::runtime_error("Call to suptitle() failed.");

  Py_DECREF(args);
  Py_DECREF(kwargs);
  Py_DECREF(res);
}

inline void axis(const std::string &option) {
  PyObject *str = PyString_FromString(option.c_str());
  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, str);

  PyObject *res = PyObject_CallObject(
      detail::_interpreter::get().s_python_function_axis, args);
  if (!res)
    throw std::runtime_error("Call to axis() failed.");

  Py_DECREF(args);
  Py_DECREF(res);
}

inline void xlabel(const std::string &str,
                   const std::map<std::string, std::string> &keywords = {}) {
  PyObject *pystr = PyString_FromString(str.c_str());
  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, pystr);

  PyObject *kwargs = PyDict_New();
  for (auto it = keywords.begin(); it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_xlabel, args, kwargs);
  if (!res)
    throw std::runtime_error("Call to xlabel() failed.");

  Py_DECREF(args);
  Py_DECREF(kwargs);
  Py_DECREF(res);
}

inline void ylabel(const std::string &str,
                   const std::map<std::string, std::string> &keywords = {}) {
  PyObject *pystr = PyString_FromString(str.c_str());
  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, pystr);

  PyObject *kwargs = PyDict_New();
  for (auto it = keywords.begin(); it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_ylabel, args, kwargs);
  if (!res)
    throw std::runtime_error("Call to ylabel() failed.");

  Py_DECREF(args);
  Py_DECREF(kwargs);
  Py_DECREF(res);
}

inline void grid(bool flag = true) {
  PyObject *pyflag = flag ? Py_True : Py_False;
  Py_INCREF(pyflag);

  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, pyflag);

  PyObject *res = PyObject_CallObject(
      detail::_interpreter::get().s_python_function_grid, args);
  if (!res)
    throw std::runtime_error("Call to grid() failed.");

  Py_DECREF(args);
  Py_DECREF(res);
}

inline void show(const bool block = true) {
  PyObject *res;
  if (block) {
    res =
        PyObject_CallObject(detail::_interpreter::get().s_python_function_show,
                            detail::_interpreter::get().s_python_empty_tuple);
  } else {
    PyObject *kwargs = PyDict_New();
    PyDict_SetItemString(kwargs, "block", Py_False);
    res =
        PyObject_Call(detail::_interpreter::get().s_python_function_show,
                      detail::_interpreter::get().s_python_empty_tuple, kwargs);
    Py_DECREF(kwargs);
  }

  if (!res)
    throw std::runtime_error("Call to show() failed.");

  Py_DECREF(res);
}

inline void close() {
  PyObject *res =
      PyObject_CallObject(detail::_interpreter::get().s_python_function_close,
                          detail::_interpreter::get().s_python_empty_tuple);

  if (!res)
    throw std::runtime_error("Call to close() failed.");

  Py_DECREF(res);
}

inline void xkcd() {
  PyObject *res;
  PyObject *kwargs = PyDict_New();

  res = PyObject_Call(detail::_interpreter::get().s_python_function_xkcd,
                      detail::_interpreter::get().s_python_empty_tuple, kwargs);

  Py_DECREF(kwargs);

  if (!res)
    throw std::runtime_error("Call to xkcd() failed.");

  Py_DECREF(res);
}

inline void draw() {
  PyObject *res =
      PyObject_CallObject(detail::_interpreter::get().s_python_function_draw,
                          detail::_interpreter::get().s_python_empty_tuple);

  if (!res)
    throw std::runtime_error("Call to draw() failed.");

  Py_DECREF(res);
}

template <typename Numeric> inline void pause(Numeric interval) {
  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, PyFloat_FromDouble(interval));

  PyObject *res = PyObject_CallObject(
      detail::_interpreter::get().s_python_function_pause, args);
  if (!res)
    throw std::runtime_error("Call to pause() failed.");

  Py_DECREF(args);
  Py_DECREF(res);
}

inline void savefig(const std::string &filename,
                    const std::map<std::string, std::string> &keywords = {}) {
  PyObject *pyfilename = PyString_FromString(filename.c_str());

  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, pyfilename);

  PyObject *kwargs = PyDict_New();
  for (auto it = keywords.begin(); it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_save, args, kwargs);
  if (!res)
    throw std::runtime_error("Call to save() failed.");

  Py_DECREF(kwargs);
  Py_DECREF(args);
  Py_DECREF(res);
}

inline void save(const std::string &filename) {
  std::cerr << "matplotlibcpp::save is deprecated, use savefig instead\n";
  matplotlibcpp::savefig(filename);
}

inline void clf() {
  PyObject *res =
      PyObject_CallObject(detail::_interpreter::get().s_python_function_clf,
                          detail::_interpreter::get().s_python_empty_tuple);

  if (!res)
    throw std::runtime_error("Call to clf() failed.");

  Py_DECREF(res);
}

inline void ion() {
  PyObject *res =
      PyObject_CallObject(detail::_interpreter::get().s_python_function_ion,
                          detail::_interpreter::get().s_python_empty_tuple);

  if (!res)
    throw std::runtime_error("Call to ion() failed.");

  Py_DECREF(res);
}

inline std::vector<std::array<double, 2>>
ginput(const int numClicks = 1,
       const std::map<std::string, std::string> &keywords = {}) {
  PyObject *args = PyTuple_New(1);
  PyTuple_SetItem(args, 0, PyLong_FromLong(numClicks));

  // construct keyword args
  PyObject *kwargs = PyDict_New();
  for (std::map<std::string, std::string>::const_iterator it = keywords.begin();
       it != keywords.end(); ++it) {
    PyDict_SetItemString(kwargs, it->first.c_str(),
                         PyUnicode_FromString(it->second.c_str()));
  }

  PyObject *res = PyObject_Call(
      detail::_interpreter::get().s_python_function_ginput, args, kwargs);

  Py_DECREF(kwargs);
  Py_DECREF(args);
  if (!res)
    throw std::runtime_error("Call to ginput() failed.");

  const size_t len = PyList_Size(res);
  std::vector<std::array<double, 2>> out;
  out.reserve(len);
  for (size_t i = 0; i < len; i++) {
    PyObject *current = PyList_GetItem(res, i);
    std::array<double, 2> position;
    position[0] = PyFloat_AsDouble(PyTuple_GetItem(current, 0));
    position[1] = PyFloat_AsDouble(PyTuple_GetItem(current, 1));
    out.push_back(position);
  }
  Py_DECREF(res);

  return out;
}

inline void tight_layout() {
  PyObject *res = PyObject_CallObject(
      detail::_interpreter::get().s_python_function_tight_layout,
      detail::_interpreter::get().s_python_empty_tuple);

  if (!res)
    throw std::runtime_error("Call to tight_layout() failed.");

  Py_DECREF(res);
}

// recursion stop for the below
template <typename... Args> bool plot() { return true; }

// enable plotting of multiple triples (x, y, format)
template <typename A, typename B, typename... Args>
bool plot(const A &a, const B &b, const std::string &format, Args... args) {
  return plot(a, b, format) && plot(args...);
}

// This class allows dynamic plots, ie changing the plotted data without
// clearing and re-plotting
class Plot {
public:
  // default initialization with plot label, some data and format
  template <typename Numeric>
  Plot(const std::string &name, const std::vector<Numeric> &x,
       const std::vector<Numeric> &y, const std::string &format = "") {

    assert(x.size() == y.size());

    PyObject *kwargs = PyDict_New();
    if (name != "")
      PyDict_SetItemString(kwargs, "label", PyString_FromString(name.c_str()));

    PyObject *xarray = get_array(x);
    PyObject *yarray = get_array(y);

    PyObject *pystring = PyString_FromString(format.c_str());

    PyObject *plot_args = PyTuple_New(3);
    PyTuple_SetItem(plot_args, 0, xarray);
    PyTuple_SetItem(plot_args, 1, yarray);
    PyTuple_SetItem(plot_args, 2, pystring);

    PyObject *res = PyObject_Call(
        detail::_interpreter::get().s_python_function_plot, plot_args, kwargs);

    Py_DECREF(kwargs);
    Py_DECREF(plot_args);

    if (res) {
      line = PyList_GetItem(res, 0);

      if (line)
        set_data_fct = PyObject_GetAttrString(line, "set_data");
      else
        Py_DECREF(line);
      Py_DECREF(res);
    }
  }

  // shorter initialization with name or format only
  // basically calls line, = plot([], [])
  Plot(const std::string &name = "", const std::string &format = "")
      : Plot(name, std::vector<double>(), std::vector<double>(), format) {}

  template <typename Numeric>
  bool update(const std::vector<Numeric> &x, const std::vector<Numeric> &y) {
    assert(x.size() == y.size());
    if (set_data_fct) {
      PyObject *xarray = get_array(x);
      PyObject *yarray = get_array(y);

      PyObject *plot_args = PyTuple_New(2);
      PyTuple_SetItem(plot_args, 0, xarray);
      PyTuple_SetItem(plot_args, 1, yarray);

      PyObject *res = PyObject_CallObject(set_data_fct, plot_args);
      if (res)
        Py_DECREF(res);
      return res;
    }
    return false;
  }

  // clears the plot but keep it available
  bool clear() { return update(std::vector<double>(), std::vector<double>()); }

  // definitely remove this line
  void remove() {
    if (line) {
      auto remove_fct = PyObject_GetAttrString(line, "remove");
      PyObject *args = PyTuple_New(0);
      PyObject *res = PyObject_CallObject(remove_fct, args);
      if (res)
        Py_DECREF(res);
    }
    decref();
  }

  ~Plot() { decref(); }

private:
  void decref() {
    if (line)
      Py_DECREF(line);
    if (set_data_fct)
      Py_DECREF(set_data_fct);
  }

  PyObject *line = nullptr;
  PyObject *set_data_fct = nullptr;
};

} // end namespace matplotlibcpp