"Not enough input arguments"

I am trying to run the below code -

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%Code:

p_initial = [0.1, 0.1, 0.1, 0.1];

options = optimoptions(@fmincon,'Display','iter','Algorithm','interior-point');

[p,fval] = fmincon(@tryone,p_initial,[],[],[],[],[],[],@errors,options)

It calls for 2 functions which are mentioned below :

%p(1), p(2) are Weibull shape parameters & p(3) is line intercept parameter, p(4) is slope parameter

function val=tryone(p,xdata, ydata)

p = [p(1), p(2), p(3), p(4)];

val = -sum(log(p(1))) -sum(log(p(2))) -(p(2)-1)*sum(log(ydata - p(3) - p(4)*xdata))+ p(1)*sum((ydata - p(3) - p(4)*xdata).^p(2));

%Constraint for Weibull errors to be positive

function [c, ceq] = errors(p,xdata,ydata)

c = ydata - p(3) - p(4)*xdata;

ceq = [ ];

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I am encountering few problems:

1) I don't know how to incorporate constraint for Weibull parameters to be positive, i.e. p(1) and p(2) to be positive.

2) I am getting an error "Not enough input arguments" for this command (loglikelihood function mentioned above) -

 val = -sum(log(p(1))) -sum(log(p(2))) -(p(2)-1)*sum(log(ydata - p(3) - p(4)*xdata))+ p(1)*sum((ydata - p(3) - p(4)*xdata).^p(2));

I am trying to run the below code -

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Can somebody please tell me how to fix this?

Answer 1

[Walter Roberson]

http://www.mathworks.com/help/matlab/math/parameterizing-functions.html