Function linesearch_backtracking

ggml.c:18484–18604

};

static enum ggml_opt_result linesearch_backtracking(
        const struct ggml_opt_params * params,
        int nx,
        float * x,
        float * fx,
        float * g,
        float * d,
        float * step,
        const float * xp,
        struct ggml_tensor * f,
        struct ggml_cgraph * gb,
        struct ggml_cplan  * cplan,
        const int np,
        struct ggml_tensor * ps[],
        bool * cancel,
        ggml_opt_callback callback,
        void * callback_data) {
    int count = 0;

    float width  = 0.0f;
    float dg     = 0.0f;
    float finit  = 0.0f;
    float dginit = 0.0f;
    float dgtest = 0.0f;

    const float dec = 0.5f;
    const float inc = 2.1f;

    const int n_accum = MAX(1, params->n_gradient_accumulation);
    const float accum_norm = 1.0f / (float) n_accum;

    if (*step <= 0.f) {
        return GGML_LINESEARCH_INVALID_PARAMETERS;
    }

    // compute the initial gradient in the search direction
    ggml_vec_dot_f32(nx, &dginit, g, d);

    // make sure that d points to a descent direction
    if (0 < dginit) {
        return GGML_LINESEARCH_FAIL;
    }

    // initialize local variables
    finit = *fx;
    dgtest = params->lbfgs.ftol*dginit;

    while (true) {
        ggml_vec_cpy_f32(nx, x, xp);
        ggml_vec_mad_f32(nx, x, d, *step);

        // evaluate the function and gradient values
        {
            ggml_opt_set_params(np, ps, x);

            *fx = 0;
            memset(g, 0, sizeof(float)*nx);
            for (int accum_step = 0; accum_step < n_accum; ++accum_step) {