got rid of offset in butterdiff

Author: pavelkomarov

pynumdiff/optimize/_optimize.py

@@ -97,7 +97,7 @@
             'proc_huberM': (0, 6),
             'meas_huberM': (0, 6)}),
     robustdiffclassic: ({'order': {1, 2, 3}, # warning: order 1 hacks the loss function when tvgamma is used, tends to win but is usually suboptimal choice in terms of true RMSE
-                  'log_qr_ratio': [k for k in range(-1, 16, 4)],
+                  'log_qr_ratio': [float(k) for k in range(-1, 16, 4)],
                         'huberM': [0., 5, 20]}, # 0. so type is float. Good choices here really depend on the data scale
                  {'log_qr_ratio': (-1, 18),
                         'huberM': (0, 1e2)}), # really only want to use l2 norm when nearby

pynumdiff/smooth_finite_difference/_smooth_finite_difference.py

@@ -170,12 +170,7 @@ def butterdiff(x, dt, params=None, options={}, filter_order=2, cutoff_freq=0.5,
     for _ in range(num_iterations):
         x_hat = scipy.signal.filtfilt(b, a, x_hat, method="pad", padlen=padlen) # applies forward and backward pass so zero phase
 
-    x_hat, dxdt_hat = finite_difference(x_hat, dt)
-
-    offset = np.mean(x) - np.mean(x_hat)
-    x_hat = x_hat + offset
-
-    return x_hat, dxdt_hat
+    return finite_difference(x_hat, dt)
 
 
 def splinediff(*args, **kwargs):

pynumdiff/tests/test_diff_methods.py

@@ -91,12 +91,12 @@ def spline_irreg_step(*args, **kwargs): return splinediff(*args, **kwargs)
                      [(0, -1), (1, 1), (0, 0), (1, 1)],
                      [(1, 1), (2, 2), (1, 1), (2, 2)],
                      [(1, 1), (3, 3), (1, 1), (3, 3)]],
-    butterdiff: [[(-13, -14), (-13, -13), (0, -1), (0, 0)],
-                 [(0, -1), (0, 0), (0, -1), (0, 0)],
-                 [(0, 0), (1, 1), (0, 0), (1, 1)],
-                 [(1, 0), (1, 1), (1, 0), (1, 1)],
-                 [(2, 2), (3, 2), (2, 2), (3, 2)],
-                 [(2, 1), (3, 3), (2, 1), (3, 3)]],
+    butterdiff: [[(-14, -15), (-13, -13), (0, -1), (1, 1)],
+                 [(-3, -3), (-2, -2), (0, -1), (1, 1)],
+                 [(-2, -3), (-1, -1), (0, -1), (1, 1)],
+                 [(-3, -3), (0, -1), (0, -1), (1, 1)],
+                 [(0, -1), (1, 1), (0, 0), (1, 1)],
+                 [(0, 0), (3, 3), (0, 0), (3, 3)]],
     first_order: [[(-25, -25), (-25, -25), (0, 0), (1, 1)],
                   [(-25, -25), (-13, -13), (0, 0), (1, 1)],
                   [(-25, -25), (0, 0), (0, 0), (1, 1)],