Function main

subprojects/llama.cpp/tests/test-opt.cpp:899–1003

int main(void) {
    ggml_log_set(nullptr, nullptr);
    ggml_backend_load_all();
    const size_t dev_count = ggml_backend_dev_count();
    printf("Testing %zu devices\n\n", dev_count);
    size_t n_ok = 0;

    std::vector<ggml_backend_dev_t> devs;
    std::vector<ggml_backend_t>     backends;

    for (size_t i = 0; i < dev_count; ++i) {
        devs.push_back(ggml_backend_dev_get(i));

        ggml_backend_t backend = ggml_backend_dev_init(devs[i], NULL);
        GGML_ASSERT(backend != NULL);

        auto * reg = ggml_backend_dev_backend_reg(devs[i]);
        auto ggml_backend_set_n_threads_fn = (ggml_backend_set_n_threads_t) ggml_backend_reg_get_proc_address(reg, "ggml_backend_set_n_threads");
        if (ggml_backend_set_n_threads_fn) {
            ggml_backend_set_n_threads_fn(backend, std::thread::hardware_concurrency() / 2);
        }
        backends.push_back(backend);
    }

    size_t n_total = 0;
    for (enum ggml_opt_optimizer_type optim : { GGML_OPT_OPTIMIZER_TYPE_ADAMW, GGML_OPT_OPTIMIZER_TYPE_SGD }) {
        for (size_t i = 0; i < dev_count; ++i) {
            // Put the backend to be tested in front so that it's prioritized:
            std::vector<ggml_backend_t> backends_modded = { backends[i] };
            backends_modded.insert(backends_modded.end(), backends.begin(), backends.end());

            ggml_backend_sched_t backend_sched = ggml_backend_sched_new(
                backends_modded.data(), nullptr, backends_modded.size(), GGML_DEFAULT_GRAPH_SIZE, false, true);

            char const* devname = ggml_backend_dev_name(devs[i]);
            printf("Backend %zu/%zu: %s\n", i + 1, dev_count, devname);
            printf("  Device description: %s\n", ggml_backend_dev_description(devs[i]));
            size_t free, total;  // NOLINT
            ggml_backend_dev_memory(devs[i], &free, &total);
            printf("  Device memory: %zu MB (%zu MB free)\n", total / 1024 / 1024, free / 1024 / 1024);
            printf("\n");

            bool skip;
            {
                struct ggml_init_params params = {
                    /*.mem_size   =*/ 6*ggml_tensor_overhead(),
                    /*.mem_buffer =*/ nullptr,
                    /*.no_alloc   =*/ true,
                };
                ggml_context * ctx = ggml_init(params);
                ggml_tensor * a = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, 1);
                ggml_set_param(a);
                ggml_tensor * b = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, 1);
                ggml_tensor * c = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, 1);
                ggml_tensor * d = ggml_new_tensor_1d(ctx, GGML_TYPE_F32, 1);

                ggml_tensor * t = nullptr;
                switch (optim) {