Fix - minor: eigval eigvec arg ordering (#132)

* fix ordering of eval and evec in eig() and eigh()

* fix ordering of evals and evecs in function call

Author: ewanwm

nuTens/propagator/const-density-solver.cpp

@@ -16,7 +16,7 @@ void ConstDensityMatterSolver::calculateEigenvalues(Tensor &eigenvectors, Tensor
         }
     }
 
-    Tensor::eigh(hamiltonian, eigenvectors, eigenvalues);
+    Tensor::eigh(hamiltonian, eigenvalues, eigenvectors);
 }
 
 void ConstDensityMatterSolver::buildElectronOuterProduct() 
@@ -38,4 +38,4 @@ void ConstDensityMatterSolver::buildElectronOuterProduct()
             Tensor::scale(Tensor::outer(mixingMatrix.getValues({0, 0, "..."}), mixingMatrix.getValues({0, 0, "..."}).conj()),
                           nuTens::constants::Groot2 * density);
     }
-}
+}

nuTens/tensors/torch-tensor.cpp

@@ -434,17 +434,17 @@ void Tensor::eig(const Tensor &t, Tensor &eVals, Tensor &eVecs)
     NT_PROFILE();
 
     auto ret = torch::linalg_eig(t._tensor);
-    eVals.setTensor(std::get<1>(ret));
-    eVecs.setTensor(std::get<0>(ret));
+    eVals.setTensor(std::get<0>(ret));
+    eVecs.setTensor(std::get<1>(ret));
 }
 
 void Tensor::eigh(const Tensor &t, Tensor &eVals, Tensor &eVecs)
 {
     NT_PROFILE();
 
     auto ret = torch::linalg_eigh(t._tensor);
-    eVals.setTensor(std::get<1>(ret));
-    eVecs.setTensor(std::get<0>(ret));
+    eVals.setTensor(std::get<0>(ret));
+    eVecs.setTensor(std::get<1>(ret));
 }
 
 void Tensor::eigvals(const Tensor &t, Tensor &eVals)