Special case: Zero eigenvectors

src/elpa1/elpa1_template.F90

@@ -136,6 +136,12 @@ function elpa_solve_evp_&
    nblk       = obj%nblk
    matrixCols = obj%local_ncols
 
+   if (nev == 0) then
+     nev = 1
+     obj%eigenvalues_only = .true.
+   endif
+
+
    call obj%get("mpi_comm_rows",mpi_comm_rows)
    call obj%get("mpi_comm_cols",mpi_comm_cols)
    call obj%get("mpi_comm_parent", mpi_comm_all)

src/elpa2/elpa2_template.F90

@@ -136,6 +136,11 @@
     nblk       = obj%nblk
     matrixCols = obj%local_ncols
 
+   if (nev == 0) then
+     nev = 1
+     obj%eigenvalues_only = .true.
+   endif
+
 #if REALCASE == 1
     call obj%get("real_kernel",kernel)
     ! check consistency between request for GPUs and defined kernel

src/elpa_index.c

@@ -620,7 +620,7 @@ static int nev_is_valid(elpa_index_t index, int n, int new_value) {
         if (!elpa_index_int_value_is_set(index, "na")) {
                 return 0;
         }
-        return 0 < new_value && new_value <= elpa_index_get_int_value(index, "na", NULL);
+        return 0 <= new_value && new_value <= elpa_index_get_int_value(index, "na", NULL);
 }
 
 static int is_positive(elpa_index_t index, int n, int new_value) {