Replace Python numerical kernels with native C execution

native/include/runtime.h

@@ -0,0 +1,34 @@
+#ifndef NATIVE_RUNTIME_H
+#define NATIVE_RUNTIME_H
+#include "model.h"
+#include <stddef.h>
+typedef struct {
+    double start, stop, sample_step, max_step, rtol, timeout;
+    int bdf, record_samples;
+    const char *cancel_path;
+} NativeOptions;
+typedef struct {
+    NativeOptions options;
+    double *times, *states;
+    size_t count, capacity, sample_index;
+    double final_time, final_state[NSTATES];
+    double wall_start, cpu_start, solve_seconds, solve_cpu_seconds, last_progress;
+    double max_accepted_step;
+    unsigned long nfev, accepted, rejected, events, starts, njev, nlu;
+    int status; /* 0 completed, 1 cancelled, 2 failed */
+    const char *message;
+} NativeRun;
+typedef int (*NativeDense)(void *context, double t, double *state);
+double native_wall_time(void);
+double native_cpu_time(void);
+int native_poll(NativeRun *run, double time);
+int native_rhs(NativeRun *run, double t, const double *y, double *dy);
+int native_append(NativeRun *run, double t, const double *y);
+int native_accept(NativeRun *run, double t, double next, const double *old,
+                  const double *trial, NativeDense dense, void *context,
+                  double *accepted_time, double *accepted_state);
+int native_rk45(NativeRun *run);
+int native_bdf(NativeRun *run);
+int native_solve(NativeRun *run);
+void native_run_free(NativeRun *run);
+#endif