fix(graph): keep local orbits at zero global gravity

Author: Coding-Dev-Tools

engraphis/dashboard_assets/engraphis-graph.js

@@ -2973,7 +2973,8 @@
       Number(opts.localSoftening) || opts.softening || 40);
     const field = galaxyBlackHoleField(bodies, Object.assign({}, opts, { softening: centralSoftening }));
     const anchor = field.anchor && field.anchor.anchor_role === 'global' ? field.anchor : null;
-    if (!anchor || !(field.gravitationalConstant > 0)) return empty;
+    if (!anchor) return empty;
+    const globalFieldActive = field.gravitationalConstant > 0;
     const timestep = Math.max(0.001, Math.min(2, Number(opts.timestep) || 1));
     const orbitalRadius = galaxyOrbitalRadiusMultiplier(opts.orbitalSpeed);
     const absoluteSpeedLimit = Math.max(0.01, Number(opts.speedLimit) || MAX_NODE_SPEED);
@@ -3039,7 +3040,12 @@
       if (!(Number.isFinite(Number(orbit.baseRadius)) && Number(orbit.baseRadius) > 0)) {
         orbit.baseRadius = Number(orbit.radius) || starRadius;
       }
-      orbit.radius = boundedRadius(orbit.baseRadius * orbitalRadius, extent * orbitalRadius);
+      /* At the zero global-gravity endpoint the black-hole carrier is stationary. Preserve its
+         current radius so local stellar members can keep orbiting that fixed carrier instead of
+         receiving a one-time radial resize from the orbital-speed presentation multiplier. */
+      orbit.radius = globalFieldActive
+        ? boundedRadius(orbit.baseRadius * orbitalRadius, extent * orbitalRadius)
+        : boundedRadius(Number(orbit.radius) || starRadius, extent);
       if (!Number.isFinite(orbit.angle)) {
         orbit.angle = seededHash(opts.layoutSeed, 'kinematic-system:' + item.id)
           / 0x100000000 * Math.PI * 2;

tests/test_graph_engine_asset.py

@@ -11858,6 +11858,52 @@ def test_kinematic_local_velocity_budget_uses_one_phase_speed() -> None:
     assert report["phaseSpeed"] == pytest.approx(report["relativeSpeed"], rel=1e-9), report
 
 
+@requires_node
+def test_kinematic_local_orbits_continue_when_global_gravity_is_zero() -> None:
+    """Zero global gravity must not disable the independent local stellar clock."""
+    report = _run_node(
+        """
+        const nodes = [
+          { id: 'black-hole', anchor_role: 'global', community_id: 'core',
+            system_anchor_id: 'black-hole', gravity_mass: 8, radius: 8,
+            x: 0, y: 0, vx: 0, vy: 0 },
+          { id: 'star', anchor_role: 'community', community_id: 'solar',
+            system_anchor_id: 'star', gravity_mass: 4, radius: 5,
+            x: 120, y: 0, vx: 0, vy: 0 },
+          { id: 'planet', community_id: 'solar', system_anchor_id: 'star',
+            orbit_tier: 1, gravity_mass: 1, radius: 2,
+            x: 150, y: 0, vx: 0, vy: 0 },
+        ];
+        const options = {
+          gravity: 0, softening: 32, centralSoftening: 40, localSoftening: 12,
+          localGravitySetting: 48, orbitalSpeed: 400, layoutSeed: 19,
+          timestep: .032, speedLimit: 48,
+        };
+        const angle = () => Math.atan2(nodes[2].y - nodes[1].y,
+          nodes[2].x - nodes[1].x);
+        const before = angle();
+        const first = I.advanceGalaxyKinematicOrbits(nodes, options);
+        const afterFirst = angle();
+        const second = I.advanceGalaxyKinematicOrbits(nodes, options);
+        const afterSecond = angle();
+        emit({ first, second,
+          localTravel: Math.atan2(Math.sin(afterSecond - before),
+            Math.cos(afterSecond - before)),
+          carrierTravel: Math.hypot(nodes[1].x - 120, nodes[1].y),
+          finite: nodes.every(node =>
+            [node.x, node.y, node.vx, node.vy].every(Number.isFinite)),
+          firstStepMoved: Math.abs(afterFirst - before) > 1e-8,
+        });
+        """
+    )
+    assert report["finite"] is True
+    assert report["first"]["satellites"] > 0
+    assert report["second"]["satellites"] > 0
+    assert report["firstStepMoved"] is True
+    assert abs(report["localTravel"]) > 1e-5
+    assert report["carrierTravel"] <= 1e-9
+
+
 @requires_node
 def test_live_carrier_is_capped_before_local_motion_budgeting() -> None:
     report = _run_node(