Error when exectued from GUI, no error when executed in Command Window

I'm having a hard time tracking this issue down.

I have four 1x15 doubles:

for i=1:15
   center(i)=double(pdata{i}{6});
   span(i)=double(pdata{i}{7});
   pts(i)=double(pdata{i}{9});
   resolution(i)=span(i)/(pts(i)-1);
end

pdata is a 1x15 cell, and each of those cells is a 1x18 cell. I have 15 parameter files (each with 18 parameters) and I am storing 3 of them, and calculating another. That all works fine.

I then calculate a few more things:

for i=1:15
   minf(i)=(center(i)-span(i)/2);
   for j=1:pts(i)
       f{i}(j)=minf(i)+(j-1)*resolution(i);
   end
   <other stuff>
end

Eventually I create a plot. Everything works as it should when I copy it and run it through the command window. However, when I run it from my GUI, which runs the same exact code, I get the error (triggered by line 2 in second section of code):

"??? Attempted to access center(1); index out of bounds because numel(center)=0."

However, when I run it through the command window (when it executes as it should) and do numel(center), ans=15 as it should.

Answer 1

[Walter Roberson]

Is all of the code you note in one continuous function? Or is it split between two functions, with the second function perhaps having a "global center" statement ?

[Jared]

It's in 2 separate functions, and center span pts and resolution are all global (just between those 2 functions).

[Walter Roberson]

I suspect you will find that you did not declare it as global in the first function, but did declare it as global in the second function. When you declare a variable as global when it has not previously been defined as a global variable and given a value, then "global" will initialize the new global variable to the empty array.

Keep in mind that you must declare a variable as "global" in EVERY routine you use it in.