Weird problem with MATLAB misbehaving..

This is the Linear regression function. My problem is when I am running one line using this function MATLAB2017a returns values but when this function is inside another function it does not run leading to error. Pls have a look at the attached snap

function [a1,a0] = linreg(x,lsqsize,lsqshift)

error(nargchk(1,3,nargin)) % # INPUTS BET'N 1 AND 3

% DEFAULT VALUES
if nargin == 1
   lsqsize = 7;
   lsqshift = 1;
elseif nargin == 2
   lsqshift = 1;
end

num_col = fix((size(x,1) - lsqsize + lsqshift)/lsqshift);
num_row = size(x,2);
for k = 1:num_col
   for l = 1:num_row
      loc = (k-1)*lsqshift+1;
      [a1(k,l),a0(k,l)] = lsqfit(x(loc:loc+lsqsize-1,l));
   end
end

end

Answer 1

[Image Analyst]

Put these lines as the first two lines inside your linreg() function:

a0 = []; % Initialize to null.
a1 = []; % Initialize to null.

Then set a breakpoint at this line

[a1(k,l),a0(k,l)] = lsqfit(x(loc:loc+lsqsize-1,l));

and then try to figure out why your code execution never ever reaches that line of code and so a1 never gets assigned at all.

[MSP]

Why is it that it runs when I use only the first line where I blue marked "This runs". How come does that run though?

[Image Analyst]

d11 is obviously different than LagR. What do you learn by stepping through with the debugger?

[Walter Roberson]

In your code being called within the function, either num_row or num_col is coming out as 0 because of the data you pass in.

I note by the way that you are calling LinReg but your function name is linreg . MATLAB is case sensitive; however, the name of the file overrides the name given on the function line.