I'm using the toolbox psignifit to plot psychometric functions from a dataset. My code looks essentially like the following:
load data.mat
options = struct;
options.sigmoidname = 'logistic';
result = psignifit(data,options); % this is where the error occurs
result.Fit
result.conf_Intervals
plotPsych(result)
and my data has essentially the same form as the sample data given in the toolbox,
data = [...
0.0010, 45.0000, 90.0000;...
0.0015, 50.0000, 90.0000;...
0.0020, 44.0000, 90.0000;...
0.0025, 44.0000, 90.0000;...
0.0030, 52.0000, 90.0000;...
0.0035, 53.0000, 90.0000;...
0.0040, 62.0000, 90.0000;...
0.0045, 64.0000, 90.0000;...
0.0050, 76.0000, 90.0000;...
0.0060, 79.0000, 90.0000;...
0.0070, 88.0000, 90.0000;...
0.0080, 90.0000, 90.0000;...
0.0100, 90.0000, 90.0000];
When I run the demo, the plotPsych function returns a figure as it is supposed to, but when I execute my script, I get the following series of errors. My question is why am I getting the error about using gammaln and what might be the right fix?
Error using gammaln
Input must be nonnegative.
Error in logLikelihood (line 75)
p = p + gammaln(n - k + b);
Error in psignifitCore>@(X)-logLikelihood(data,options,X(1),X(2),X(3),X(4),X(5)) (line 80)
fun = @(X) -logLikelihood(data, options, X(1), X(2), X(3), X(4), X(5));
Error in fminsearch (line 325)
x(:) = xr; fxr = funfcn(x,varargin{:});
Error in psignifitCore (line 97)
Fit = fminsearch(fun, x0,optimiseOptions); %MATLAB standard choice
Error in psignifit (line 242)
result = psignifitCore(data, options);
Error in signifit_myscript (line 31)
result = psignifit(data,HDDV);
I've run the toolbox on my data in the past with success, so I first tried to restart Matlab, to no avail. I then tried to remove and add back psignifit-master to the path, but this also didn't seem to solve the issue.
Thanks in advance.
