Merge pull request #384 from emstoudenmire/qn_randomITensor

Add error checks for zero blocks in randomITensor QN version
ITensor · Feb 8, 2021 · 477aaed · 477aaed
2 parents fb83fde + d494752
commit 477aaed
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/itensor/itensor.cc b/itensor/itensor.cc
@@ -1580,6 +1580,7 @@ randomITensor(QN q, IndexSet const& is)
     ITensor T;
     auto dat = QDenseReal{is,q};
     T = ITensor(std::move(is),std::move(dat));
+    if(nnz(T) == 0) Error("Requested QN for random ITensor resulted in zero allowed blocks (QN not satisfiable by any settings of the indices)");
     T.generate(detail::quickran);
     return T;
     }
@@ -1594,6 +1595,7 @@ randomITensorC(QN q, IndexSet const& is)
     ITensor T;
     auto dat = QDenseCplx{is,q};
     T = ITensor(std::move(is),std::move(dat));
+    if(nnz(T) == 0) Error("Requested QN for random ITensor resulted in zero allowed blocks (QN not satisfiable by any settings of the indices)");
     T.generate(detail::quickranCplx);
     return T;
     }