Non-constant expression or empty matrix

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Yuri Rzhanov 2019-1-11

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编辑： Walter Roberson 2019-1-12

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Hi,

I have this error in Coder when am converting the following code, in the last line:

if ~isempty(coder.target)
    coder.varsize('lattice', [100 100]);
    lattice = zeros(0,0);
end
...
lattice = init_lattice(points,i);
if ~isempty(coder.target)
  proposed_lattice = { 0 0 0 0 };
  coder.varsize('proposed_lattice');
  energy = zeros(4);
end
    
for j=1:4
  proposed_lattice{j} = grow_lattice(lattice,points,j);
  energy(j) = lattice_energy(proposed_lattice{j},points);
end
    
[~,min_idx] = min(energy);
    
if energy(min_idx) < previous_energy
  lattice = proposed_lattice{min_idx};
...

'lattice' grows in size after each reassignment. First assignment by 'init_lattice' makes it 3*3, but as I understand, 'varsize' allows it to grow until 100*100. Would appreciate any clues.

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Walter Roberson 2019-1-11

编辑：Walter Roberson 2019-1-12

I would be more comfortable if you defined energy with two parameters to zeros .zeroes(4) is 4x4 but you are assigning to it like it was 1d column vector.

Yuri Rzhanov 2019-1-12

在 MATLAB Online 中打开

I can write

energy(j,1) = lattice_energy(proposed_lattice{j},points);
...
    if energy(min_idx,1) < previous_energy
      lattice = proposed_lattice{min_idx};
    else
        break;
    end
    

but this doesn't change anything. Checking code readiness doesn't show anything wrong, but the coder (while generating trial code) throws this error, pointing to 'min_idx' which is a scalar. 'proposed_lattice' is a cell array, so {} are suitable, right?

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