insect-tools/time_series_to_kinematics_file.m at master · pseudospectators/insect-tools · GitHub

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function time_series_to_kinematics_file(time, alpha, phi, theta, file, nfft)
%% time_series_to_kinematics_file(time, alpha, phi, theta, file, nfft)
%--------------------------------------------------------------------------
% from a given time series of the angles alpha, phi and theta, perform a
% Fourier approximation (i.e. it is possible to use less Fourier modes
% in order to apply smoothing), and write the Fourier coefficients to a
% kinematics file useable in FLUSI code.
%--------------------------------------------------------------------------
% INPUT:
%   time, alpha, phi, theta: the time series of the angles to be approximated
%   file: kinematics.in file to be written to
%   nfft:   3x1 vector with the number of Fourier modes for the 3 angles. If
%           all are zero, then we'll run interactive mode
% OUTPUT:
%   written to the file "file" directly.
%--------------------------------------------------------------------------
mode='';
if (sum(nfft)==0)
    mode='interactive';
end

if (max(alpha)<2*pi)
    warning('max(alpha)<2*pi: maybe you gave me radiants? I need degrees!');
end

if (max(phi)<2*pi)
    warning('max(phi)<2*pi: maybe you gave me radiants? I need degrees!');
end

if (max(theta)<2*pi)
    warning('max(theta)<2*pi: maybe you gave me radiants? I need degrees!');
end

if (strcmp(mode,'interactive'))
    %% decide nfft for alpha,phi,theta interactively
    h=msgbox('determine nfft interactively for ALPHA'); uiwait(h);
    nfft(1) = interactive_fourier_fit( time, alpha );

    h=msgbox('determine nfft interactively for PHI'); uiwait(h);
    nfft(2) = interactive_fourier_fit( time, phi );

    h=msgbox('determine nfft interactively for THETA'); uiwait(h);
    nfft(3) = interactive_fourier_fit( time, theta );
end


%% do the fourier approximation:
kine.nfft_alpha = nfft(1);
kine.nfft_phi   = nfft(2);
kine.nfft_theta = nfft(3);

% get Fourier coefficients (by least squares fit)
[ai_alpha,bi_alpha] = Fseries (time, alpha,kine.nfft_alpha);
[ai_phi,bi_phi]     = Fseries (time, phi,  kine.nfft_phi);
[ai_theta,bi_theta] = Fseries (time, theta,kine.nfft_theta);

% store coefficients in a struct
kine.a0_alpha = ai_alpha(1);
kine.ai_alpha = ai_alpha(2:end);
kine.bi_alpha = bi_alpha;

kine.a0_phi = ai_phi(1);
kine.ai_phi = ai_phi(2:end);
kine.bi_phi = bi_phi;

kine.a0_theta = ai_theta(1);
kine.ai_theta = ai_theta(2:end);
kine.bi_theta = bi_theta;

% write to file - be happy!
write_kinematics_file(file, kine, 'kinematics file generated by time_series_to_kinematics_file' )

end