stardis-solver

commit 1bcdc87731beaa41af785e8ea7ac68157a13d597
parent ef7ebfcae52edcef15d6670aacece69d93b20a28
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Fri,  4 Apr 2025 15:14:46 +0200

Improve the robustness of the WoS algorithm

The way the numerical problems were handled could itself suffer from
numerical problems that did not allow the path to be saved, which is
then rejected. This commit takes the way in which positions close to the
boundary are handled one step further, to avoid such situations as far
as possible.

Diffstat:
M
src/sdis_heat_path_conductive_wos_Xd.h
 | 
53
++++++++++++++++++++++++++++-------------------------

1 file changed, 28 insertions(+), 25 deletions(-)
diff --git a/src/sdis_heat_path_conductive_wos_Xd.h b/src/sdis_heat_path_conductive_wos_Xd.h
@@ -415,11 +415,7 @@ XD(setup_hit_rt)
   /* Fetch interface properties and check path consistency */
   scene_get_enclosure_ids(scn, hit->prim.prim_id, enc_ids);
   if(enc_ids[side] != rwalk->enc_id) {
-    log_err(scn->dev,
-      "%s:%s: the conductive path has reached an invalid interface. "
-      "Unexpected enclosure -- pos=("FORMAT_VECX"), side=%s\n",
-      __FILE__, FUNC_NAME, SPLITX(tgt), side == SDIS_FRONT ? "front" : "back");
-    res = RES_BAD_OP_IRRECOVERABLE;
+    res = RES_BAD_OP;
     goto error;
   }
 
@@ -508,6 +504,7 @@ XD(sample_next_position)
      * want to move to is actually inside the epsilon shell. In this case, the
      * trajectory will be moved to this interface in the next step anyway. */
     } else {
+      struct sXd(hit) hit_rt = SXD_HIT_NULL;
       float rt_pos[DIM] = {0};
       float rt_dir[DIM] = {0};
       float rt_range[2] = {0, 0};
@@ -516,27 +513,33 @@ XD(sample_next_position)
       fX_set_dX(rt_dir, dir);
       rt_range[0] = 0;
       rt_range[1] = (float)INF;
-      SXD(scene_view_trace_ray(scn->sXd(view), rt_pos, rt_dir, rt_range, NULL, &hit));
-
-      /* An intersection should be found. If not, we can do nothing and simply
-       * reject the path.
-       *
-       * TODO: we could take the treatment of numerical problems a step further
-       * by sampling other directions and trying to move in them again. But at
-       * present, and until we have proof to the contrary, we assume that the
-       * rejection of a path should not occur, or that it will be so rare that
-       * we don't care to save it. */
-      if(SXD_HIT_NONE(&hit)) {
-        log_err(scn->dev,
-          "%s:%s: unable to find the next diffusion position -- "
-          "position=("FORMAT_VECX"),  direction=("FORMAT_VECX"), distance=%g\n",
-          __FILE__, FUNC_NAME, SPLITX(pos), SPLITX(dir), wos_distance);
-        res = RES_BAD_OP_IRRECOVERABLE;
-        goto error;
+      SXD(scene_view_trace_ray
+        (scn->sXd(view), rt_pos, rt_dir, rt_range, NULL, &hit_rt));
+
+      if(SXD_HIT_NONE(&hit_rt)) {
+        /* The lack of intersection is probably due to a current position close
+         * to the boundary. And although it is detected in the solid by WoS, the
+         * specific numerical errors of the ray-tracing operator may contradict
+         * the WoS algorithm, which relies on the closest point operator. But
+         * since the position is close to the boundary, it can be snaped to it*/
+        res = XD(setup_hit_wos)(scn, &hit, rwalk);
+        if(res != RES_OK) goto error;
+
+      } else {
+        res = XD(setup_hit_rt)(scn, rwalk->vtx.P, dir, &hit_rt, rwalk);
+        if(res != RES_OK) {
+          /* An error occurs while handling ray intersection. This means that
+           * the Ray-Tracing operator find an invalid intersection regarding the
+           * current enclosure in which the path should be sampled. As in the
+           * case of the lack of intersection (see above) this means that the
+           * position is close to the enclosure boundary and that the ray missed
+           * it. So, As previously, the position can be simply snaped to it
+           * since one can assumes that the current position is is the right
+           * enclosure */
+          res = XD(setup_hit_wos)(scn, &hit, rwalk);
+          if(res != RES_OK) goto error;
+        }
       }
-
-      res = XD(setup_hit_rt)(scn, rwalk->vtx.P, dir, &hit, rwalk);
-      if(res != RES_OK) goto error;
     }
   }