/usr/share/psychtoolbox-3/Psychometric/FitWeibAlphTAFC.m is in psychtoolbox-3-common 3.0.14.20170103+git6-g605ff5c.dfsg1-1build1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 | function [alpha,beta,thresh92] = FitWeibAlphTAFC(inputs,nCorrect,nError,...
alpha0,beta0)
% [alpha,beta,thresh92] = FitWeibAlphTAFC(inputs,nCorrect,nError,...
% alpha0,beta0)
%
% Maximum likelihood fit of a Weibull function to psychometric data,
% search only on alpha with fixed beta as passed.
%
% Requires the optimization toolbox.
%
% INPUTS:
% inputs: contains the input levels
% nCorrect: contains the number of yes responses at
% the corresponding input level
% nError: contains the number of no responses at
% the corresponding input level
% alpha0: Initial guess for alpha, empty for default [1].
% beta0: Value for beta
% OUTPUTS:
% alpha Weibull alpha parameter
% beta Weibull beta parameter
% thresh92 92% percent correct threshold
%
% See also: FitWeibTAFC, FitFitWeibYN, FitCumNormYN, FitLogitYN
%
% 8/25/94 dhb, ccc Cleaned comments, return 92% correct threshold.
% 2/8/97 dhb Added check for optimization toolbox.
% 4/26/97 dhb Change threshold to thresh92.
% 4/18/02 dhb Fix reference to undefined variable 'levels'.
% dhb Suppress warnings in calls to optimization toolbox.
% 3/5/05 dhb Update for optimization toolbox version 2.
% Initial parameters
if (isempty(alpha0))
x0(1) = mean(inputs);
else
x0(1) = alpha0;
end
% Check for needed optimization toolbox, and version.
if (exist('fminunc') == 2)
options = optimset;
options = optimset(options,'Diagnostics','off','Display','off');
options = optimset(options,'LargeScale','off');
x1 = fminunc('WeibAlphTAFCFitFun',x0,options,beta0,inputs,nCorrect,nError);
x = fminunc('WeibAlphTAFCFitFun',x1,options,beta0,inputs,nCorrect,nError);
elseif (exist('fminu') == 2)
options = foptions;
state = warning; warning('off');
x1 = fminu('WeibAlphTAFCFitFun',x0,options,[],beta0,inputs,nCorrect,nError);
x = fminu('WeibAlphTAFCFitFun',x1,options,[],beta0,inputs,nCorrect,nError);
warning(state);
else
error('FitWeibTAFCAlph requires the optional Matlab Optimization Toolbox from Mathworks');
end
% Extract parameters
alpha = x(1);
beta = beta0;
% Compute threshold from fit parameters
thresh92 = FindThreshWeibTAFC(0.92,alpha,beta);
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