init

tests/test_geodesic.c

@@ -0,0 +1,43 @@
+#include "geodesic.h"
+
+#include <math.h>
+#include <stdio.h>
+
+static int nearly_equal(double a, double b) { return fabs(a - b) < 1e-12; }
+
+static int check_ray(const SpacetimeSource *source,
+                     const ObserverState *observer,
+                     const double local_direction[3],
+                     const double expected[3]) {
+  const GeodesicTraceConfig config = {.coordinate_time_step = 0.25,
+                                      .max_steps = 100};
+  RayEndpoint ray =
+      geodesic_trace_past(source, observer, local_direction, &config);
+  if (ray.status != RAY_ENDPOINT_ESCAPED ||
+      !nearly_equal(ray.frequency_ratio, 1.0) ||
+      !nearly_equal(ray.n_infinity[0], expected[0]) ||
+      !nearly_equal(ray.n_infinity[1], expected[1]) ||
+      !nearly_equal(ray.n_infinity[2], expected[2])) {
+    fprintf(stderr, "flat-space geodesic regression failed\n");
+    return 1;
+  }
+  return 0;
+}
+
+int main(void) {
+  SpacetimeSource source = {0};
+  const ObserverState observer = observer_fixed_at_origin();
+  if (spacetime_create_minkowski(&source, 10.0))
+    return 1;
+  int result = check_ray(&source, &observer, (double[]){1.0, 0.0, 0.0},
+                         (double[]){0.0, 0.0, -1.0}) ||
+               check_ray(&source, &observer, (double[]){0.0, 0.0, 1.0},
+                         (double[]){1.0, 0.0, 0.0});
+  const ObserverState look_at_ra_zero =
+      observer_fixed_at_origin_look_at(0.0, 0.0);
+  result = result || check_ray(&source, &look_at_ra_zero,
+                               (double[]){1.0, 0.0, 0.0},
+                               (double[]){1.0, 0.0, 0.0});
+  spacetime_destroy(&source);
+  return result;
+}