main.c

/**
 * Author: Baptiste Coudray
 * School: HEPIA
 * Class: ITI-3
 * Year 2020-2021
 */

#include <stdio.h>
#include <stddef.h>
#include "stdlib.h"
#include <mpi.h>
#include "lbm.h"
#include "../futhark_mpi/dispatch.h"

#define INDEX_3D_TO_1D(y, x, z, nb_columns, nb_depths) x + HEIGHT* (y + WIDTH* z)

#define N_ITERATIONS 200
#define NB_VALUES 27

typedef struct lbm_values {
    float values[NB_VALUES];
} lbm_values_t;

void init_chunk_lbm(chunk_info_t *ci) {
    lbm_values_t *data32 = ci->data;
    for (size_t i = 0; i < ci->count; ++i) {
        for (int l = 0; l < NB_VALUES; ++l) {
            data32[i].values[l] = ((float) rand() / (float) rand());
        }
    }
}

struct futhark_f32_4d *
convert_chunk_with_envelope(struct futhark_context *fc, const void *data, int64_t dim0, int64_t dim1, int64_t dim2) {
    return futhark_new_f32_4d(fc, data, dim0, dim1, dim2, NB_VALUES);
}

void compute_next_lbm(struct dispatch_context *dc, struct futhark_context *fc, chunk_info_t *ci) {
    struct futhark_f32_4d *fut_chunk_with_envelope = get_chunk_with_envelope(dc, fc, 1, convert_chunk_with_envelope);

    struct futhark_f32_4d *fut_next_chunk_lbm;
    futhark_entry_next_chunk_lbm(fc, &fut_next_chunk_lbm, fut_chunk_with_envelope);
    futhark_context_sync(fc);

    futhark_values_f32_4d(fc, fut_next_chunk_lbm, ci->data);
    futhark_context_sync(fc);

    futhark_free_f32_4d(fc, fut_chunk_with_envelope);
    futhark_free_f32_4d(fc, fut_next_chunk_lbm);
}

int main(int argc, char *argv[]) {
    if (argc < 4) {
        printf("usage: mpirun -n <nb_proc> %s <height> <width> <depth>\n", argv[0]);
        return EXIT_FAILURE;
    }

    MPI_Init(&argc, &argv);
    int my_rank;
    int world_size;
    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
    MPI_Comm_size(MPI_COMM_WORLD, &world_size);

    struct futhark_context_config *fut_config = futhark_context_config_new();
    struct futhark_context *fut_context = futhark_context_new(fut_config);

    int lbm_dimensions[3] = {atoi(argv[1]), atoi(argv[2]), atoi(argv[3])};

    // https://stackoverflow.com/a/33624425
    int count = 1;
    int array_of_blocklengths[] = {NB_VALUES};
    MPI_Aint array_of_displacements[] = {offsetof(struct lbm_values, values)};
    MPI_Datatype array_of_types[] = {MPI_FLOAT};
    MPI_Datatype tmp_type, my_mpi_type;
    MPI_Aint lb, extent;

    MPI_Type_create_struct(count, array_of_blocklengths, array_of_displacements,
                           array_of_types, &tmp_type);
    MPI_Type_get_extent(tmp_type, &lb, &extent);
    MPI_Type_create_resized(tmp_type, lb, extent, &my_mpi_type);
    MPI_Type_commit(&my_mpi_type);

    struct dispatch_context *disp_context = dispatch_context_new(lbm_dimensions, my_mpi_type, 3);
    chunk_info_t ci = get_chunk_info(disp_context);
    chunk_info_print(&ci);
    init_chunk_lbm(&ci);

    for (int i = 0; i < N_ITERATIONS; ++i) {
        compute_next_lbm(disp_context, fut_context, &ci);
    }

    dispatch_context_free(disp_context);
    futhark_context_config_free(fut_config);
    futhark_context_free(fut_context);
    MPI_Type_free(&tmp_type);
    MPI_Type_free(&my_mpi_type);
    return MPI_Finalize();
}