skip electron in mixture valence calculation (#67)

Author: markleader

source/mixture.f90

@@ -728,6 +728,8 @@ subroutine mixture_get_valence(self, vm, vp)
         ! Loop over the species
         vm = 0.0d0; vp = 0.0d0
         do i = 1, ne
+            ! "E" is a pseudo-element used for ionized bookkeeping, not a real atom.
+            if (self%element_names(i) == 'E') cycle
             v = get_atom_valence(self%element_names(i))
             if (v < 0.0d0) then
                 vm(i) = vm(i) + v

source/mixture_test.pf

@@ -74,6 +74,23 @@ contains
 
     end subroutine
 
+    @test
+    subroutine test_get_valence_ignores_electron
+        type(Mixture) :: mix
+        real(dp) :: vm(2), vp(2)
+        real(dp), parameter :: tol = 1.d-14
+
+        mix = Mixture(all_thermo, ['N2 ', 'N2+', 'N  ', 'N+ ', 'e- '], ions=.true.)
+        call mix%get_valence(vm, vp)
+
+        @assertEqual('N', mix%element_names(1))
+        @assertEqual('E', mix%element_names(2))
+        @assertTrue(abs(vm(1)) <= tol)
+        @assertTrue(abs(vp(1)) <= tol)
+        @assertTrue(abs(vm(2)) <= tol)
+        @assertTrue(abs(vp(2)) <= tol)
+    end subroutine
+
     @test
     subroutine test_sort_condensed