Fix adjoint gradient with conductivities (NanoComp#1830)

* damp_fix

* increase run time

Co-authored-by: Mo Chen <mochen@Mos-MacBook-Pro.local>

python/tests/test_adjoint_solver.py

@@ -519,6 +519,32 @@ def test_damping(self):
             tol = 0.06 if mp.is_single_precision() else 0.03
             self.assertClose(adj_scale,fd_grad,epsilon=tol)
 
+    def test_damping(self):
+        print("*** TESTING CONDUCTIVITIES ***")
+
+        for frequencies in [[1/1.58, fcen, 1/1.53]]:
+            ## compute gradient using adjoint solver
+            adjsol_obj, adjsol_grad = adjoint_solver_damping(p, frequencies)
+
+            ## compute unperturbed S12
+            S12_unperturbed = forward_simulation_damping(p, frequencies)
+
+            ## compare objective results
+            print("S12 -- adjoint solver: {}, traditional simulation: {}".format(adjsol_obj,S12_unperturbed))
+            self.assertClose(adjsol_obj,S12_unperturbed,epsilon=1e-6)
+
+            ## compute perturbed S12
+            S12_perturbed = forward_simulation_damping(p+dp, frequencies)
+
+            ## compare gradients
+            if adjsol_grad.ndim < 2:
+                adjsol_grad = np.expand_dims(adjsol_grad,axis=1)
+            adj_scale = (dp[None,:]@adjsol_grad).flatten()
+            fd_grad = S12_perturbed-S12_unperturbed
+            print("Directional derivative -- adjoint solver: {}, FD: {}".format(adj_scale,fd_grad))
+            tol = 0.06 if mp.is_single_precision() else 0.03
+            self.assertClose(adj_scale,fd_grad,epsilon=tol)
+
     def test_damping(self):
         print("*** TESTING CONDUCTIVITIES ***")