Explicit dynamics core: central differences, one-point hex8 with hourglass control, nodal-pressure tet4, solve.explicit (M10 X1) (#27)

* Model: explicit dynamic steps (end time, increment scale and cap, output intervals, initial velocities, rigid walls, hourglass and bulk viscosity controls); deck writers refuse them Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * fem: uniform-strain hex8 and tet4 kinematics, Flanagan–Belytschko hourglass shape vectors, element frequency bound Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * Explicit solver crate (L2): central differences with lumped mass, one-point hex8 with Flanagan–Belytschko hourglass control, Bonet–Burton tet4, bulk viscosity, rigid walls, energy account; wave and impact verification Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * Engine: solve.explicit and solve.history commands, explicit results in the session and solve.probe; cantilever period against the modal solver Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * Docs: explicit solver in the architecture, roadmap (M10 started), parity and literature (Part H) Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * Simplify: Model::select_step shared by both solvers, Procedure::sets/is_dynamic, fused per-increment passes without allocation, shared element tail, generic command caps Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * Catalogue: solve.explicit is ready; solve.history beside solve.probe Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * Rebase onto the implicit couplings work: Procedure is no longer Copy Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm --------- Co-authored-by: jyviko <2501648+jyviko@users.noreply.github.com> Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-13 18:28:32 -04:00
1 parent 48039639cb
commit d45a2da5b5
@@ -234,6 +234,9 @@ struct Deck<'m> {

 /// The solution sequence of a list of steps, or why there is none.
 fn solution(steps: &[&Step]) -> std::result::Result<u32, String> {
+    if let Some(s) = steps.iter().find(|s| matches!(s.procedure, Procedure::ExplicitDynamic(_))) {
+        return Err(format!("step `{}`: explicit dynamic steps (Nastran's linear solutions have none)", s.name));
+    }
    let statics = steps.iter().find(|s| matches!(s.procedure, Procedure::Static {}));
    let modes = steps.iter().find(|s| matches!(s.procedure, Procedure::Frequency { .. }));
    match (statics, modes) {
@@ -581,8 +584,8 @@ impl<'m> Deck<'m> {
            comment(&mut out, "eigenvalue extraction");
        }
        for sub in &self.subcases {
-            if let (Some(sid), Procedure::Frequency { modes, min_hz, max_hz }) = (sub.method, sub.step.procedure) {
-                Card::new("EIGRL").int(sid).opt(min_hz).opt(max_hz).int(modes).write(&mut out)?;
+            if let (Some(sid), Procedure::Frequency { modes, min_hz, max_hz }) = (sub.method, &sub.step.procedure) {
+                Card::new("EIGRL").int(sid).opt(*min_hz).opt(*max_hz).int(*modes).write(&mut out)?;
            }
        }
        out.push_str("ENDDATA\n");