fix memory leaks in structure and fields load during checkpointing (N…

…anoComp#1872)

* fix memory leaks in structure and fields load during checkpointing

* delete the chi1inv and fields array if it exists and reallocate

* in unit test, set gaussian source cutoff to 0 due to off-by-1 timestep counter bug

* remove cutoff=0 from unit tests

* lazily allocate H only if B is not NULL

* allocate fields array for H in PML region

src/fields_dump.cpp

@@ -184,12 +184,17 @@ void fields::load_fields_chunk_field(h5file *h5f, bool single_parallel_file,
           size_t n = num_f[(chunk_i * NUM_FIELD_COMPONENTS + c) * 2 + d];
           realnum **f = field_ptr_getter(chunks[i], c, d);
           if (n == 0) {
-            delete[] * f;
+            delete[] *f;
             *f = NULL;
           } else {
             if (n != ntot)
               meep::abort("grid size mismatch %zd vs %zd in fields::load", n, ntot);
-            *f = new realnum[ntot];
+            // here we need to allocate the fields array for H in the PML region
+            // because of H = B in fields_chunk::alloc_f whereby H is lazily
+            // allocated in fields_chunk::update_eh during the first timestep
+            const direction d_c = component_direction(c);
+            if (!(*f) || (*f && is_magnetic(component(c)) && chunks[i]->s->sigsize[d_c] > 1))
+              *f = new realnum[ntot];
             my_ntot += ntot;
           }
         }

src/structure_dump.cpp

@@ -604,7 +604,7 @@ void structure::load(const char *filename, bool single_parallel_file) {
           }
           else {
             if (n != ntot) meep::abort("grid size mismatch %zd vs %zd in structure::load", n, ntot);
-            chunks[i]->chi1inv[c][d] = new realnum[ntot];
+            if (!chunks[i]->chi1inv[c][d]) chunks[i]->chi1inv[c][d] = new realnum[ntot];
             my_ntot += ntot;
           }
         }

tests/dump_load.cpp

@@ -169,7 +169,6 @@ int test_periodic(double eps(const vec &), int splitting, const char *tmpdir) {
   double ttot = 17.0;
 
   grid_volume gv = vol3d(1.5, 0.5, 1.0, a);
-  structure s1(gv, eps);
   structure s(gv, eps, no_pml(), identity(), splitting);
 
   std::string filename_prefix =