main.c

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

#include <stdio.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) + (nb_columns) * ((y) + (nb_depths) * (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) {
    float *data32 = ci->data;
    for (int i = 0; i < ci->dimensions[0]; ++i) {
        for (int j = 0; j < ci->dimensions[1]; ++j) {
            for (int k = 0; k < ci->dimensions[2]; ++k) {
                int idx = INDEX_3D_TO_1D(i, j, k, ci->dimensions[1], ci->dimensions[2]);
                data32[idx] = rand() % 2;
            }
        }
    }
}


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])};

    MPI_Datatype cell;
    int lengths[1] = {NB_VALUES};
    MPI_Aint displacements[3];
    struct lbm_values dummy_values;
    MPI_Aint base_address;
    MPI_Get_address(&dummy_values, &base_address);
    displacements[0] = MPI_Aint_diff(displacements[0], base_address);

    MPI_Datatype types[1] = {MPI_FLOAT};
    MPI_Type_create_struct(1, lengths, displacements, types, &cell);
    MPI_Type_commit(&cell);


    struct dispatch_context *disp_context = dispatch_context_new(lbm_dimensions, cell, 3);
    dispatch_context_print(disp_context);
    chunk_info_t ci = get_chunk_info(disp_context);
    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);
    return MPI_Finalize();
}