'too many input arguments' in mhsample
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I am having the error 'too many input arguments' during my function call which itself is called by another built-in MatLab function 'mhsample'. I have not been able to figure out any reason for this error. Following is the snippet of the code:
% specification of unnormalized posterior pdf to sample from
% specification of proposal distribution
% specification of random number generator from proposal distribution
generator = @(x) (xPrior(:,1)+rand(7,1).*(xPrior(:,2)-xPrior(:,1)));
% calculation of posterior of model parameters (lambda)
smpl = mhsample(x0,nsamples,'pdf',pdfPost,'proppdf',pdfProp,'proprnd',generator);
Following is the error message:
Error using mhsample (line 117)
Error occurred while trying to evaluate the user-supplied
proppdf function '@(x)priorDist(x,xPrior)'.
Error in metroPolisHastingSampling (line 33)
Error using @(x)priorDist(x,xPrior)
Too many input arguments.
'metroPolisHastingSampling' is the name of the script I have used for implementing Metropolis-Hastings sampling method.
So, the error is in proposal distribution which only has one input argument? So, why am I getting this error? Any useful comment is appreciated?
The code for priorDist is as follows:
function [p] = priorDist(x,xprior)
I have provided all other codes below: Here is the code for 'PosteriorDist':
function ptr = posteriorDist(x,C,artificialNetwork)
lh=likelihoodPost(artificialNetwork,x,C); % likelihood of observation given these parameters
priorParam = priorDist(x); % computation of joint prior of model parameters
ptr=lh*priorParam; % computation of unnormalized posterior
rest of the definitions are
I have taken a random just for testing purposes. artificialNetwork contains information and relevant data.
Walter Roberson 2017-9-2
"proppdf takes two arguments as inputs with the same type and size as start."
"The proposal distribution q(x,y) gives the probability density for choosing x as the next point when y is the current point. It is sometimes written as q(x|y)."
should probably just be
pdfProp = @priorDist;