hang remove friction and dt logging update

examples/hang.ipynb

@@ -45,7 +45,11 @@
     "gravity = param.get(\"gravity\")\n",
     "\n",
     "# set strain-limiting upper bound 1% (0.5%+0.5%)\n",
-    "param.set(\"strain-limit-eps\", 0.005).set(\"strain-limit-tau\", 0.005)\n",
+    "(\n",
+    "    param.set(\"strain-limit-eps\", 0.005)\n",
+    "    .set(\"strain-limit-tau\", 0.005)\n",
+    "    .set(\"friction\", 0.0)\n",
+    ")\n",
     "\n",
     "# set the maximal video frame to 200\n",
     "param.set(\"frames\", 200)\n",

src/cpp/main/main.cu

@@ -342,6 +342,12 @@ StepResult advance() {
 
     float dt = param->dt;
 
+    // Name: Step Size
+    // Format: list[(vid_time,float)]
+    // Description:
+    // Target step size.
+    logging.mark("dt", dt);
+
     if (shell_face_count) {
         utility::compute_svd(data, data.vertex.curr, svd, prm);
         tmp_scalar.clear();
@@ -664,6 +670,17 @@ StepResult advance() {
                 // Total count of Newton's steps consumed in the single step.
                 logging.mark("newton_steps", step);
 
+                // Name: Final Step Size
+                // Format: list[(vid_time,float)]
+                // Description:
+                // Actual step size advanced in the simulation.
+                // For most of the cases, this value is the same as the step
+                // size specified in the parameter. However, the actual step
+                // size is reduced by `toi_advanced` and may be also reduced
+                // when the option `enable_retry` is set to
+                // true and the PCG fails.
+                logging.mark("final_dt", dt);
+
                 param->prev_dt = dt;
                 param->time += param->prev_dt;
 
@@ -685,15 +702,6 @@ StepResult advance() {
         logging.mark("retry_count", retry_count);
     }
     result.retry_count = retry_count;
-
-    // Name: Step Size
-    // Format: list[(vid_time,float)]
-    // Description:
-    // Actual step size advanced in the simulation.
-    // For most of the cases, this value is the same as the step size specified
-    // in the parameter. However, the actual step size is reduced when the
-    // option `enable_retry` is set to true and the PCG fails.
-    logging.mark("dt", dt);
     return result;
 }