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