docs: @Override
      public void solve(DMatrixRMaj B , DMatrixRMaj X ) {
          if( B.numRows != n ) {
              throw new IllegalArgumentException("Unexpected matrix size");
          }
          X.reshape(n,B.numCols);
  
          if(decomposer.isLower()) {
              solveLower(A,B,X,vv);
          } else {
              throw new RuntimeException("Implement");
          }
      }