docs: public static void columnMaxAbs( DMatrixSparseCSC A , double []values ) {
          if( values.length < A.numCols )
              throw new IllegalArgumentException("Array is too small. "+values.length+" < "+A.numCols);
  
          for (int i = 0; i < A.numCols; i++) {
              int idx0 = A.col_idx[i];
              int idx1 = A.col_idx[i+1];
  
              double maxabs = 0;
              for (int j = idx0; j < idx1; j++) {
                  double v = Math.abs(A.nz_values[j]);
                  if( v > maxabs )
                      maxabs = v;
              }
              values[i] = maxabs;
          }
      }