MATLAB: Classification in Parfor Loops

Question

parfor xIndex=1:2:c

          for yIndex=1:2:c
            x = xvec(xIndex);
            y = yvec(yIndex);
            M(xIndex, yIndex) = EscapeVelocity(-0.123+0.745*1i, x+y*1i,  m);
          end
end

MatLab says "The variable M in a parfor cannot be classified"

I would appreciate any explanation of why this occurs and how to correct it.

Answer 1

Try constructing

xvec2 = xvec(1:2:c);
nxvec2 = length(xvec2);
yvec2 = yvec(1:2:c);
nyvec2 = length(yvec2);
M2 = zeros(nxvec2, nyvec2);

Then

parfor for xindex = 1 : nxvec2
  x = xvec2(xindex);
  for yindex = 1 : nyvec2
    y = yvec2(yindex);
    M2(xIndex, yIndex) = EscapeVelocity(-0.123+0.745*1i, x+y*1i,  m);
  end
end

Then

M(1:2:c, 1:2:c) = M2;