Method prop_down

examples/machine_learning/rbm.cpp:66–69

    }

    array prop_down(const array &h) {
        array v_bias_tile = tile(v_bias, h.dims(0));
        return sigmoid(v_bias_tile + matmul(h, weights));
    }

    void gibbs_vhv(array &vt, array &ht, const array &v, int k = 1) {
        vt = v;