// Text p. 45 shows quadratic is special case of Func3.
// This indicates a test case for Func3
func TestFunc3(t *testing.T) {
f0 := func(x float64) float64 { return x * x }
f1 := func(x float64) float64 { return x }
f2 := func(x float64) float64 { return 1 }
a, b, c := fit.Func3(qdata, f0, f1, f2)
if a != -1 || b != -2 || c != 2 {
t.Fatal(a, b, c)
}
}
func ExampleFunc3() {
// Example 4.c, p. 44.
data := []struct{ X, Y float64 }{
{3, .0433},
{20, .2532},
{34, .3386},
{50, .3560},
{75, .4983},
{88, .7577},
{111, 1.4585},
{129, 1.8628},
{143, 1.8264},
{160, 1.2431},
{183, -.2043},
{200, -1.2431},
{218, -1.8422},
{230, -1.8726},
{248, -1.4889},
{269, -.8372},
{290, -.4377},
{303, -.3640},
{320, -.3508},
{344, -.2126},
}
// fix up data to have X in radians
for i := range data {
data[i].X *= math.Pi / 180
}
f0 := math.Sin
f1 := func(x float64) float64 { return math.Sin(2 * x) }
f2 := func(x float64) float64 { return math.Sin(3 * x) }
a, b, c := fit.Func3(data, f0, f1, f2)
// output four decimal places corresponding to precision of Y values.
fmt.Printf("%.4f, %.4f, %.4f\n", a, b, c)
// Output:
// 1.2000, -0.7700, 0.3900
}