Calculations/Data-Analyzer/+Analyzer/fitTwoGaussianCurvesToRadialSpectralDistribution.m

149 lines
5.8 KiB
Matlab

function [fitResults, rawCurves] = fitTwoGaussianCurvesToRadialSpectralDistribution(S_k_all, k_rho_vals, varargin)
%% fitTwoGaussianCurvesToRadialSpectralDistribution
% Fits a two-Gaussian model to multiple radial spectral curves (S(k_rho)),
% truncating each curve to user-specified k_rho and amplitude ranges.
%
% Author: Karthik
% Date: 2025-10-15
% Version: 1.0
%
% Inputs:
% S_k_all - 1xN cell array of radial spectral curves
% k_rho_vals - vector of corresponding k_rho values
%
% Optional name-value pairs:
% 'KRhoRange' - [k_min, k_max] (default: [min(k_rho_vals), max(k_rho_vals)])
% 'AmplitudeRange' - [y_min, y_max] (default: [0, Inf])
% 'ResidualThreshold', 'PositionThreshold', 'AmplitudeThreshold' as before
%
% Outputs:
% fitResults - struct array with fields:
% .pFit, .kFit, .xFit, .yFit, .kFine, .isValid, .fitMaxKRho
% rawCurves - struct array of truncated raw curves for plotting
% --- Parse optional inputs ---
p = inputParser;
addParameter(p, 'KRhoRange', [min(k_rho_vals), max(k_rho_vals)], @(x) isnumeric(x) && numel(x)==2);
addParameter(p, 'AmplitudeRange', [0, Inf], @(x) isnumeric(x) && numel(x)==2);
addParameter(p, 'ResidualThreshold', 0.3, @(x) isnumeric(x) && isscalar(x));
addParameter(p, 'PositionThreshold', 0.1, @(x) isnumeric(x) && isscalar(x));
addParameter(p, 'AmplitudeThreshold', 0.5, @(x) isnumeric(x) && isscalar(x));
parse(p, varargin{:});
opts = p.Results;
Ncurves = numel(S_k_all);
fitResults = struct('pFit',[],'kFit',[],'xFit',[],'yFit',[],...
'kFine',[],'isValid',[],'fitMaxKRho',[]);
rawCurves = struct('x', cell(1, Ncurves), 'k', cell(1, Ncurves));
for k = 1:Ncurves
% --- Truncate curve to k_rho and amplitude ranges ---
xRaw = S_k_all{k};
% --- Normalize and smooth ---
xNorm = xRaw / max(xRaw);
xSmooth = smooth(xNorm, 5, 'moving');
mask = (k_rho_vals(:) >= opts.KRhoRange(1)) & (k_rho_vals(:) <= opts.KRhoRange(2)) & ...
(xSmooth(:) >= opts.AmplitudeRange(1)) & (xSmooth(:) <= opts.AmplitudeRange(2));
x = xSmooth(mask);
kVals = k_rho_vals(mask);
rawCurves(k).x = x;
rawCurves(k).k = kVals;
if isempty(x)
warning('Curve %d is empty after truncation.', k);
fitResults(k) = fillZeroStructRadial(kVals, opts.KRhoRange(2));
continue;
elseif numel(x) < 5
warning('Curve %d has too few points after truncation, skipping.', k);
fitResults(k) = fillNaNStructRadial();
continue;
end
try
% --- Detect peaks ---
curveAmp = max(x) - min(x);
minProm = opts.AmplitudeThreshold * curveAmp;
[pk, locIdx] = findpeaks(x, 'MinPeakProminence', minProm);
kPeaks = kVals(locIdx);
%% Generic two-Gaussian
twoGauss = @(p,k) ...
p(1)*exp(-0.5*((k - p(2))/max(p(3),1e-6)).^2) + ...
p(4)*exp(-0.5*((k - p(5))/max(p(6),1e-6)).^2);
secondaryIdx = find(kPeaks > opts.PositionThreshold, 1, 'first');
if ~isempty(secondaryIdx)
kSecondary = kPeaks(secondaryIdx);
secondaryAmp = pk(secondaryIdx);
A1_guess = opts.AmplitudeRange(2);
mu1_guess = 0.0;
sigma1_guess = 0.1 * kSecondary;
A2_guess = secondaryAmp;
mu2_guess = kSecondary;
sigma2_guess = 0.1 * kSecondary;
p0 = [A1_guess, mu1_guess, sigma1_guess, A2_guess, mu2_guess, sigma2_guess];
else
p0 = [opts.AmplitudeRange(2), 0, 0.1, 0.01, opts.KRhoRange(2)/3, 0.1];
end
lb = [0, 0, 1e-6, 0, opts.PositionThreshold, 1e-6];
ub = [2, opts.KRhoRange(2)/2, opts.KRhoRange(2), 2, opts.KRhoRange(2), opts.KRhoRange(2)];
optsLSQ = optimoptions('lsqcurvefit','Display','off', ...
'MaxFunctionEvaluations',1e4,'MaxIterations',1e4);
pFit = lsqcurvefit(twoGauss, p0, kVals(:), x(:), lb, ub, optsLSQ);
if pFit(4) <= 1e-3
pFit(4) = 0;
pFit(5:6) = NaN;
end
fitMaxKRho = max(pFit(5), pFit(2));
kFine = linspace(min(kVals), max(kVals), 500);
yFit = twoGauss(pFit, kFine);
if ~isnan(pFit)
fitResults(k).pFit = pFit;
fitResults(k).kFit = kVals;
fitResults(k).xFit = x;
fitResults(k).kFine = kFine;
fitResults(k).yFit = yFit;
fitResults(k).isValid = true;
fitResults(k).fitMaxKRho = fitMaxKRho;
end
catch
warning('Curve %d fit failed completely.', k);
fitResults(k) = fillNaNStructRadial();
end
end
end
%% --- Helper: NaN struct for failed fits ---
function s = fillNaNStructRadial()
s = struct( ...
'pFit', nan(1,6), ...
'kFit', nan, ...
'xFit', nan, ...
'yFit', nan, ...
'kFine', nan, ...
'isValid', false, ...
'fitMaxKRho', nan ...
);
end
%% --- Helper: Zero struct for empty curves ---
function s = fillZeroStructRadial(kVals, MaxKRho)
s = struct( ...
'pFit', zeros(1,6), ...
'kFit', kVals, ...
'xFit', zeros(size(kVals)), ...
'yFit', zeros(size(kVals)), ...
'kFine', zeros(1,500), ...
'isValid', false, ...
'fitMaxKRho', MaxKRho ...
);
end