Creating an array from nested while loop

I have a motion analysis problem I need to do, but I don't know how to create an array that will store all the possible values after I complete the calculation. In essence, Im trying to create an array from two different vectors. The following script is what I have.

% Input Variables
P=1;
B=15;
y=25;
a=20;

%while loop for y=5:24
while y>4
    y=25-P
%     While loop for B=15:90
    while B<91
        z(y,B)=(a^2+y^2-2*a*y*cos(B*(pi/180))).^.5;
        Sigma(y,B)=acos((y^2-a^2-z(y,B).^2)/(-2*a.*z(y,B)));
        Sigmad(y,B)=Sigma(y,B)*(180/pi);
        B=B+1;
    end
    P(y)=P+1

end
z=z(z~=0);
Sigmad=Sigmad(Sigmad~=0);

I believe it may be a syntax issue, but I'm not too familiar with how matlab deals with its matrix/array syntax.

[Image Analyst]

I pasted it in and the code runs and spews out a bunch of numbers with no error messages. Exactly what is wrong with it? What is the main output variable you're looking at? What is it now, and what do you need it to be?

[Adam Doty]

I want it to create a 24x76 array (specifically for z and sigmad) storing all the values for the ranges indicated. Now it just gives me column vectors for those two. Strangely, it gives me the array I want for sigma, but populated with mostly zeroes.

[Adam Doty]

It seems like no matter what I do, the data is only stored into an array on the last run of the my "y-loop". Any help to solve this issue would be SSSSSOOOOOOO appreciated. Its been boggling my mind for days now.

Answer 1

[Jan]

The loops look very strange:

P=1;
y=25;
while y>4
  y=25-P
  ...
  P(y)=P+1
end

P becomes a vector in P(y)=P+1 and inthe 2nd iteration y is a vector also. The inner loop would fail with the error message, that y^2 is not valid, because you can only square scalars and square matrices. But this error does not appear, because B is still 92 from the first iteration of the outer loop.

Therefore I assume that there are 2 problems concerning the loops. Better use clear and clean for loops instead of the while loops. What about this:

a=20;  
for y=5:24
   for B=15:90
      z(y,B)     = sqrt(a^2+y^2-2*a*y*cos(B*(pi/180)));
      Sigma(y,B) = acos((y^2-a^2-z(y,B).^2)/(-2*a.*z(y,B)))*(180/pi);
   end
end
z=z(z~=0);
Sigmad=Sigmad(Sigmad~=0);

Perhaps you need some adjustments of the loop counters.