docs: @Override
      public void solve(ZMatrixRMaj B, ZMatrixRMaj X) {
          if( X.numRows != numCols )
              throw new IllegalArgumentException("Unexpected dimensions for X");
          else if( B.numRows != numRows || B.numCols != X.numCols )
              throw new IllegalArgumentException("Unexpected dimensions for B");
  
          int BnumCols = B.numCols;
  
          Y.reshape(numRows,1);
          Z.reshape(numRows,1);
  
          // solve each column one by one
          for( int colB = 0; colB < BnumCols; colB++ ) {
  
              // make a copy of this column in the vector
              for( int i = 0; i < numRows; i++ ) {
                  int indexB = B.getIndex(i,colB);
                  Y.data[i*2]   = B.data[indexB];
                  Y.data[i*2+1] = B.data[indexB+1];
              }
  
              // Solve Qa=b
              // a = Q'b
              CommonOps_ZDRM.mult(Qt, Y, Z);
  
              // solve for Rx = b using the standard upper triangular solver
              TriangularSolver_ZDRM.solveU(R.data, Z.data, numCols);
  
              // save the results
              for( int i = 0; i < numCols; i++ ) {
                  X.set(i,colB,Z.data[i*2],Z.data[i*2+1]);
              }
          }
      }