docs: public static DMatrixRMaj minRows(DMatrixRMaj input , DMatrixRMaj output ) {
          if( output == null ) {
              output = new DMatrixRMaj(input.numRows,1);
          } else {
              output.reshape(input.numRows,1);
          }
  
          for( int row = 0; row < input.numRows; row++ ) {
              double min = Double.MAX_VALUE;
  
              int end = (row+1)*input.numCols;
              for( int index = row*input.numCols; index < end; index++ ) {
                  double v = input.data[index];
                  if( v < min )
                      min = v;
              }
  
              output.set(row,min);
          }
          return output;
      }