sandbox/hugoj/benchmark_cpu_gpu/turbulence_benchmark.c

Decaying two-dimensional turbulence

This code is a modified version of turbulence.c. I added output at beginning and end of simulation, and when setting BENCHMARK=1 the movie is not generated and the GPU is not outputing anything to the screen.

TODO: - fixme: the movie generated stutters when runnning with the movie output on HPC GPU. Temporary fix: outputs only snapshots

#include "navier-stokes/stream.h"

The domain is square of size unity by default. The default resolution is constant at 256^2 but can be change using command line arguments.

int main (int argc, char * argv[]) {
  init_grid (argc > 1 ? atoi(argv[1]) : 256);
  run();
}

The initial condition for vorticity is just a white noise in the range [-1:1] .

event init (i = 0) {
  double a = 1. [0,-1];
  foreach (cpu)
    omega[] = a*noise();
}

We generate images of the vorticity field every 4 timesteps up to t=1000. We fix the colorscale to [-0.3:0.3].

The expected output is like the movie below

#if !BENCHMARK
event output (t += 1; t <= 1000) {
  output_ppm (omega, min = -0.3, max = 0.3, file = "omega.mp4");
}
#endif

event snap_ini (t=0) {
  output_ppm (omega, min = -0.3, max = 0.3, file = "omega_ini");
}
event snap_end (t=1000) {
  output_ppm (omega, min = -0.3, max = 0.3, file = "omega_end");
}



#if !BENCHMARK
#if _GPU && SHOW
event display (i++)
  output_ppm (omega, min = -0.3, max = 0.3, fps = 30, fp = NULL);
#endif
#endif

Benchmark on GPUs