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 * in the documentation and/or other materials provided with the
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#include "src/core/lib/transport/pid_controller.h"

#include <math.h>

#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/string_util.h>
#include <grpc/support/useful.h>
#include "src/core/lib/support/string.h"
#include "test/core/util/test_config.h"

static void test_noop(void) {
  gpr_log(GPR_INFO, "test_noop");
  grpc_pid_controller pid;
  grpc_pid_controller_init(&pid, 1, 1, 1);
}

static void test_simple_convergence(double gain_p, double gain_i, double gain_d,
                                    double dt, double set_point, double start) {
  gpr_log(GPR_INFO,
          "test_simple_convergence(p=%lf, i=%lf, d=%lf); dt=%lf set_point=%lf "
          "start=%lf",
          gain_p, gain_i, gain_d, dt, set_point, start);
  grpc_pid_controller pid;
  grpc_pid_controller_init(&pid, 0.2, 0.1, 0.1);

  double current = start;

  for (int i = 0; i < 1000; i++) {
    current += grpc_pid_controller_update(&pid, set_point - current, 1);
  }

  GPR_ASSERT(fabs(set_point - current) < 0.1);
  GPR_ASSERT(fabs(pid.error_integral) < 0.1);
}

int main(int argc, char **argv) {
  grpc_test_init(argc, argv);
  test_noop();
  test_simple_convergence(0.2, 0, 0, 1, 100, 0);
  test_simple_convergence(0.2, 0.1, 0, 1, 100, 0);
  test_simple_convergence(0.2, 0.1, 0.1, 1, 100, 0);
  return 0;
}