MATLAB Compiler

Nonscalar Arrays

(fold_non_scalar_mxarrays) This optimization is very similar to fold_scalar_mxarrays. It folds nonscalar mxArray values into compile-time arrays that are initialized at program start-up. This can have a large performance impact if you are constructing arrays that use [] or {} within a loop. This optimization makes the code less readable. For example:

• function y = test
  y = [ 1 0; 0 1] * [ pi pi/2; -pi -pi/2 ];
  

If you compile this with the -O none option, you get

• ...
  mlfAssign(
    &y,
    mclMtimes(
      mlfDoubleMatrix(2, 2, _array0_, (double *)NULL),
      mlfDoubleMatrix(2, 2, _array1_, (double *)NULL)));
  ...
  

Compiling with -O none -O fold_non_scalar_mxarrays:on gives

• ...
  mlfAssign(&y, _mxarray4_);
  ...
  

Optimizing Arrays

Scalars