code: public static DMatrix4x4 convert(DMatrixRMaj input , DMatrix4x4 output ) {
          if( output == null)
              output = new DMatrix4x4();
  
          if( input.getNumRows() != output.getNumRows() )
              throw new IllegalArgumentException("Number of rows do not match");
          if( input.getNumCols() != output.getNumCols() )
              throw new IllegalArgumentException("Number of columns do not match");
  
          output.a11 = input.data[0];
          output.a12 = input.data[1];
          output.a13 = input.data[2];
          output.a14 = input.data[3];
          output.a21 = input.data[4];
          output.a22 = input.data[5];
          output.a23 = input.data[6];
          output.a24 = input.data[7];
          output.a31 = input.data[8];
          output.a32 = input.data[9];
          output.a33 = input.data[10];
          output.a34 = input.data[11];
          output.a41 = input.data[12];
          output.a42 = input.data[13];
          output.a43 = input.data[14];
          output.a44 = input.data[15];
  
          return output;
      }
docs: Converts {@link DMatrixRMaj} into {@link DMatrix4x4}
  
  @param input Input matrix.
  @param output Output matrix.  If null a new matrix will be declared.
  @return Converted matrix.