public static <T> RBFNetwork<T> fit(T[] x, double[] y, RBF<T>[] rbf) {
        return fit(x, y, rbf, false);
    }
@Test
    public void testCPU() {
        System.out.println("CPU");

        MathEx.setSeed(19650218); // to get repeatable results.

        double[][] x = MathEx.clone(CPU.x);
        MathEx.standardize(x);
        RegressionValidations<RBFNetwork<double[]>> result = CrossValidation.regression(10, x, CPU.y,
                (xi, yi) -> RBFNetwork.fit(xi, yi, RBF.fit(xi, 20, 5.0)));

        System.out.println(result);
        assertEquals(18.0997, result.avg.rmse, 1E-4);
    }