code: public static double findMaxRow( final int blockLength ,
                                            final DSubmatrixD1 Y ,
                                            final int row , final int colStart ) {
          final int height = Math.min(blockLength , Y.row1-Y.row0);
  
          final double dataY[] = Y.original.data;
  
          double max = 0;
  
          for( int j = Y.col0; j < Y.col1; j += blockLength ) {
              int width = Math.min( blockLength , Y.col1 - j );
  
              int index = Y.row0*Y.original.numCols + height*j + row*width;
  
              if( j == Y.col0 ) {
                  index += colStart;
  
                  for( int k = colStart; k < width; k++ ) {
                      double v = Math.abs(dataY[index++]);
                      if( v > max ) {
                          max = v;
                      }
                  }
              } else {
                  for( int k = 0; k < width; k++ ) {
                      double v = Math.abs(dataY[index++]);
                      if( v > max ) {
                          max = v;
                      }
                  }
              }
          }
  
          return max;
      }
docs: Finds the element in the column with the largest absolute value. The offset
  from zero is automatically taken in account based on the column.