findPivot() [1/3]

size_t DMatLUinPlace< M2::ARingCCC >::findPivot ( size_t row, size_t col )

inlineprivate

Definition at line 206 of file dmat-lu-inplace.hpp.

{
  // Look at elements A[row,col], A[row+1,col], ..., A[nrows-1, col]
  // Return the index r s.y. abs(A[r,col]) is maximum over all of these
 
  const M2::ARingRRR& RR = ring().real_ring();
  M2::ARingRRR::Element largest(RR), abs(RR);
  size_t best_row_so_far = static_cast<size_t>(-1);
 
  RR.set_zero(largest);
 
  for (size_t i = row; i < mLU.numRows(); i++)
    {
      ring().abs(abs, mLU.entry(i, col));
      if (RR.compare_elems(abs, largest) > 0)
        {
          best_row_so_far = i;
          RR.set(largest, abs);
        }
    }
  return best_row_so_far;
}