Function TestSolveCubicFormula

util_test.go:313–338

(t *testing.T)

}

func TestSolveCubicFormula(t *testing.T) {
	var tests = []struct {
		a, b, c, d float64
		x1, x2, x3 float64
	}{
		{0.0, 1.0, 1.0, 0.25, -0.5, math.NaN(), math.NaN()},     // is quadratic formula
		{1.0, -15.0, 75.0, -125.0, 5.0, math.NaN(), math.NaN()}, // c0 == 0, c1 == 0
		{1.0, -3.0, -6.0, 8.0, -2.0, 1.0, 4.0},                  // c0 == 0, c1 < 0
		{1.0, -15.0, 75.0, -124.0, 4.0, math.NaN(), math.NaN()}, // c1 == 0, 0 < c0
		{1.0, -15.0, 75.0, -126.0, 6.0, math.NaN(), math.NaN()}, // c1 == 0, c0 < 0
		{1.0, 0.0, -7.0, 6.0, -3.0, 1.0, 2.0},                   // 0 < delta
		{1.0, -3.0, -9.0, -5.0, -1.0, 5.0, math.NaN()},          // delta == 0
		{1.0, -4.0, 2.0, -8.0, 4.0, math.NaN(), math.NaN()},     // delta < 0, 0 < tmp
		{1.0, -4.0, 2.0, 7.0, -1.0, math.NaN(), math.NaN()},     // delta < 0, tmp < 0
		{16.0, -24.0, 24.0, -8.0, 0.5, math.NaN(), math.NaN()},
	}

	for _, tt := range tests {
		t.Run(fmt.Sprintf("(%v %v %v %v)", tt.a, tt.b, tt.c, tt.d), func(t *testing.T) {
			x1, x2, x3 := solveCubicFormula(tt.a, tt.b, tt.c, tt.d)
			test.Float(t, x1, tt.x1)
			test.Float(t, x2, tt.x2)
			test.Float(t, x3, tt.x3)
		})
	}
}

func TestGaussLegendre(t *testing.T) {
	test.Float(t, gaussLegendre3(math.Log, 0.0, 1.0), -0.9476723836)