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Fix FourierFields adjoint for D and B fields in isotropic media #2095

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merged 5 commits into from
Jun 23, 2022
Merged

Fix FourierFields adjoint for D and B fields in isotropic media #2095

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bc70d31
deal with D and B fields
mawc2019 Jun 7, 2022
a816bc9
add unit test
mawc2019 Jun 17, 2022
22cd1bc
adjust tolerance in unit test
mawc2019 Jun 17, 2022
aaad415
adjust tolerance further
mawc2019 Jun 20, 2022
50e6f3f
adjust tolerance further
mawc2019 Jun 20, 2022
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35 changes: 18 additions & 17 deletions python/tests/test_adjoint_solver.py
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Original file line number Diff line number Diff line change
Expand Up @@ -204,7 +204,7 @@ def forward_simulation_complex_fields(design_params, frequencies=None):
material=matgrid)]

sim = mp.Simulation(resolution=resolution,
cell_size=cell_size,
cell_size=cell_size,default_material=silicon,
k_point=k_point,
boundary_layers=pml_x,
sources=pt_source,
Expand All @@ -213,23 +213,23 @@ def forward_simulation_complex_fields(design_params, frequencies=None):
if not frequencies:
frequencies = [fcen]

mode = sim.add_dft_fields([mp.Ez],
mode = sim.add_dft_fields([mp.Dz],
frequencies,
center=mp.Vector3(0.9),
size=mp.Vector3(0.2,0.5),
yee_grid=False)

sim.run(until_after_sources=mp.stop_when_dft_decayed())

Ez2 = []
Dz2 = []
for f in range(len(frequencies)):
Ez_dft = sim.get_dft_array(mode, mp.Ez, f)
Ez2.append(np.power(np.abs(Ez_dft[3,9]),2))
Ez2 = np.array(Ez2)
Dz_dft = sim.get_dft_array(mode, mp.Dz, f)
Dz2.append(np.power(np.abs(Dz_dft[3,9]),2))
Dz2 = np.array(Dz2)

sim.reset_meep()

return Ez2
return Dz2


def adjoint_solver_complex_fields(design_params, frequencies=None):
Expand All @@ -249,7 +249,7 @@ def adjoint_solver_complex_fields(design_params, frequencies=None):
material=matgrid)]

sim = mp.Simulation(resolution=resolution,
cell_size=cell_size,
cell_size=cell_size,default_material=silicon,
k_point=k_point,
boundary_layers=pml_x,
sources=pt_source,
Expand All @@ -261,7 +261,7 @@ def adjoint_solver_complex_fields(design_params, frequencies=None):
obj_list = [mpa.FourierFields(sim,
mp.Volume(center=mp.Vector3(0.9),
size=mp.Vector3(0.2,0.5)),
mp.Ez)]
mp.Dz)]

def J(dft_mon):
return npa.power(npa.abs(dft_mon[:,3,9]),2)
Expand Down Expand Up @@ -505,23 +505,24 @@ def test_complex_fields(self):
## compute gradient using adjoint solver
adjsol_obj, adjsol_grad = adjoint_solver_complex_fields(p, frequencies)

## compute unperturbed |Ez|^2
Ez2_unperturbed = forward_simulation_complex_fields(p, frequencies)
## compute unperturbed |Dz|^2
Dz2_unperturbed = forward_simulation_complex_fields(p, frequencies)

## compare objective results
print("Ez2 -- adjoint solver: {}, traditional simulation: {}".format(adjsol_obj,Ez2_unperturbed))
self.assertClose(adjsol_obj,Ez2_unperturbed,epsilon=1e-6)
print("Dz2 -- adjoint solver: {}, traditional simulation: {}".format(adjsol_obj,Dz2_unperturbed))
tol = 1e-5 if mp.is_single_precision() else 1e-6
self.assertClose(adjsol_obj,Dz2_unperturbed,epsilon=tol)

## compute perturbed |Ez|^2
Ez2_perturbed = forward_simulation_complex_fields(p+dp, frequencies)
## compute perturbed |Dz|^2
Dz2_perturbed = forward_simulation_complex_fields(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 = Ez2_perturbed-Ez2_unperturbed
fd_grad = Dz2_perturbed-Dz2_unperturbed
print("Directional derivative -- adjoint solver: {}, FD: {}".format(adj_scale,fd_grad))
tol = 0.018 if mp.is_single_precision() else 0.002
tol = 0.06 if mp.is_single_precision() else 0.002
self.assertClose(adj_scale,fd_grad,epsilon=tol)

def test_damping(self):
Expand Down
17 changes: 14 additions & 3 deletions src/dft.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1468,7 +1468,10 @@ std::vector<struct sourcedata> dft_fields::fourier_sourcedata(const volume &wher
std::vector<ptrdiff_t> idx_arr;
std::vector<std::complex<double> > amp_arr;
std::complex<double> EH0 = std::complex<double>(0,0);
sourcedata temp_struct = {component(f->c), idx_arr, f->fc->chunk_idx, amp_arr};
component c = component(f->c);
direction cd = component_direction(c);
sourcedata temp_struct = {c, idx_arr, f->fc->chunk_idx, amp_arr};

int position_array[3] = {0, 0, 0}; // array indicating the position of a point relative to the minimum corner of the monitor

LOOP_OVER_IVECS(f->fc->gv, f->is, f->ie, idx) {
Expand All @@ -1491,7 +1494,11 @@ std::vector<struct sourcedata> dft_fields::fourier_sourcedata(const volume &wher
temp_struct.idx_arr.push_back(idx);
for (size_t i = 0; i < Nfreq; ++i) {
EH0 = dJ_weight*dJ[reduced_grid_size*i+idx_1d];
if (is_E_or_D(temp_struct.near_fd_comp)) EH0 *= -1;

if (is_electric(c)) EH0 *= -1;
if (is_D(c) && f->fc->s->chi1inv[c - Dx + Ex][cd]) EH0 /= -f->fc->s->chi1inv[c - Dx + Ex][cd][idx];
if (is_B(c) && f->fc->s->chi1inv[c - Bx + Hx][cd]) EH0 /= f->fc->s->chi1inv[c - Bx + Hx][cd][idx];

EH0 /= f->S.multiplicity(ix0);
temp_struct.amp_arr.push_back(EH0);
}
Expand All @@ -1503,7 +1510,11 @@ std::vector<struct sourcedata> dft_fields::fourier_sourcedata(const volume &wher
temp_struct.idx_arr.push_back(site_ind[j]);
for (size_t i = 0; i < Nfreq; ++i) {
EH0 = dJ_weight*dJ[reduced_grid_size*i+idx_1d]*0.25; // split the amplitude of the adjoint source into four parts
if (is_E_or_D(temp_struct.near_fd_comp)) EH0 *= -1;

if (is_electric(c)) EH0 *= -1;
if (is_D(c) && f->fc->s->chi1inv[c - Dx + Ex][cd]) EH0 /= -f->fc->s->chi1inv[c - Dx + Ex][cd][idx];
if (is_B(c) && f->fc->s->chi1inv[c - Bx + Hx][cd]) EH0 /= f->fc->s->chi1inv[c - Bx + Hx][cd][idx];

EH0 /= f->S.multiplicity(ix0);
temp_struct.amp_arr.push_back(EH0);
}
Expand Down