column_permute()

template<typename CoeffRing>

bool SMat< CoeffRing >::column_permute	(	size_t	start_col,
		M2_arrayint	perm )

Definition at line 1032 of file smat.hpp.

{
  size_t ncols_to_permute = perm->len;
  bool *done = newarray_atomic(bool, ncols_to_permute);
  sparsevec **tmpvecs = newarray(sparsevec *, ncols_to_permute);
  for (size_t i = 0; i < ncols_to_permute; i++) done[i] = true;
  for (size_t i = 0; i < ncols_to_permute; i++)
    {
      size_t j = perm->array[i];
      if (!done[j])
        {
          ERROR("expected permutation");
          freemem(done);
          return false;
        }
      done[j] = false;
    }
  for (size_t i = 0; i < ncols_to_permute; i++)
    tmpvecs[i] = columns_[start_col + perm->array[i]];
  for (size_t i = 0; i < ncols_to_permute; i++)
    columns_[start_col + i] = tmpvecs[i];
  freemem(tmpvecs);
  freemem(done);
  return true;
}

References columns_, ERROR, freemem(), newarray, and newarray_atomic.

Referenced by MatElementaryOps< SMat< RT > >::column_permute().