test_statistics.c

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/**
 * @file test_statistics.c
 * @brief C unit tests for particle statistics kernels and CSV output.
 */
 
#include "test_support.h"
 
#include "particle_statistics.h"
 
#include <stdio.h>
#include <string.h>
/**
 * @brief Tests MSD CSV generation for a populated particle swarm.
 */
 
static PetscErrorCode TestComputeParticleMSDWritesCSV(void)
{
    SimCtx *simCtx = NULL;
    UserCtx *user = NULL;
    char tmpdir[PETSC_MAX_PATH_LEN];
    char csv_prefix[PETSC_MAX_PATH_LEN];
    char csv_path[PETSC_MAX_PATH_LEN];
    FILE *file = NULL;
    char header[512];
    char row[512];
    PetscReal (*pos_arr)[3] = NULL;
 
    PetscFunctionBeginUser;
    PetscCall(PicurvCreateMinimalContexts(&simCtx, &user, 4, 4, 4));
    PetscCall(PicurvCreateSwarmPair(user, 2, "ske"));
    simCtx->dt = 1.0;
    simCtx->ren = 1.0;
    simCtx->schmidt_number = 1.0;
    simCtx->psrc_x = 0.0;
    simCtx->psrc_y = 0.0;
    simCtx->psrc_z = 0.0;
 
    PetscCall(PicurvMakeTempDir(tmpdir, sizeof(tmpdir)));
    PetscCall(PetscSNPrintf(csv_prefix, sizeof(csv_prefix), "%s/stats", tmpdir));
    PetscCall(PetscSNPrintf(csv_path, sizeof(csv_path), "%s_msd.csv", csv_prefix));
 
    PetscCall(DMSwarmGetField(user->swarm, "position", NULL, NULL, (void *)&pos_arr));
    pos_arr[0][0] = 1.0;
    pos_arr[0][1] = 0.0;
    pos_arr[0][2] = 0.0;
    pos_arr[1][0] = -1.0;
    pos_arr[1][1] = 0.0;
    pos_arr[1][2] = 0.0;
    PetscCall(DMSwarmRestoreField(user->swarm, "position", NULL, NULL, (void *)&pos_arr));
 
    PetscCall(ComputeParticleMSD(user, csv_prefix, 1));
    PetscCall(PicurvAssertFileExists(csv_path, "ComputeParticleMSD should emit a CSV summary"));
 
    file = fopen(csv_path, "r");
    PetscCheck(file != NULL, PETSC_COMM_SELF, PETSC_ERR_FILE_OPEN, "Failed to open generated stats CSV '%s'.", csv_path);
    PetscCheck(fgets(header, sizeof(header), file) != NULL, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "CSV header is missing.");
    PetscCheck(fgets(row, sizeof(row), file) != NULL, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "CSV data row is missing.");
    fclose(file);
 
    PetscCall(PicurvAssertBool((PetscBool)(strstr(header, "MSD_total") != NULL),
                               "MSD CSV header should contain MSD_total"));
    PetscCall(PicurvAssertBool((PetscBool)(strstr(row, "2") != NULL),
                               "MSD CSV row should include the particle count"));
 
    PetscCall(PicurvRemoveTempDir(tmpdir));
    PetscCall(PicurvDestroyMinimalContexts(&simCtx, &user));
    PetscFunctionReturn(0);
}
/**
 * @brief Tests that empty swarms do not emit MSD CSV output.
 */
 
static PetscErrorCode TestComputeParticleMSDEmptySwarmNoOutput(void)
{
    SimCtx *simCtx = NULL;
    UserCtx *user = NULL;
    char tmpdir[PETSC_MAX_PATH_LEN];
    char csv_prefix[PETSC_MAX_PATH_LEN];
    char csv_path[PETSC_MAX_PATH_LEN];
    PetscBool exists = PETSC_FALSE;
 
    PetscFunctionBeginUser;
    PetscCall(PicurvCreateMinimalContexts(&simCtx, &user, 4, 4, 4));
    PetscCall(PicurvCreateSwarmPair(user, 0, "ske"));
 
    PetscCall(PicurvMakeTempDir(tmpdir, sizeof(tmpdir)));
    PetscCall(PetscSNPrintf(csv_prefix, sizeof(csv_prefix), "%s/stats", tmpdir));
    PetscCall(PetscSNPrintf(csv_path, sizeof(csv_path), "%s_msd.csv", csv_prefix));
 
    PetscCall(ComputeParticleMSD(user, csv_prefix, 5));
    PetscCall(VerifyPathExistence(csv_path, PETSC_FALSE, PETSC_TRUE, "MSD CSV for empty swarm", &exists));
    PetscCall(PicurvAssertBool((PetscBool)!exists,
                               "ComputeParticleMSD should not write output when no particles are present"));
 
    PetscCall(PicurvRemoveTempDir(tmpdir));
    PetscCall(PicurvDestroyMinimalContexts(&simCtx, &user));
    PetscFunctionReturn(0);
}
/**
 * @brief Runs the unit-post-statistics PETSc test binary.
 */
 
int main(int argc, char **argv)
{
    PetscErrorCode ierr;
    const PicurvTestCase cases[] = {
        {"compute-particle-msd-writes-csv", TestComputeParticleMSDWritesCSV},
        {"compute-particle-msd-empty-swarm-no-output", TestComputeParticleMSDEmptySwarmNoOutput},
    };
 
    ierr = PetscInitialize(&argc, &argv, NULL, "PICurv statistics tests");
    if (ierr) {
        return (int)ierr;
    }
 
    ierr = PicurvRunTests("unit-post-statistics", cases, sizeof(cases) / sizeof(cases[0]));
    if (ierr) {
        PetscFinalize();
        return (int)ierr;
    }
 
    ierr = PetscFinalize();
    return (int)ierr;
}