mirror of
https://github.com/gonum/gonum.git
synced 2025-10-31 02:26:59 +08:00
66 lines
2.0 KiB
Go
66 lines
2.0 KiB
Go
// Copyright ©2019 The Gonum Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package integrate
|
|
|
|
import (
|
|
"math"
|
|
"testing"
|
|
|
|
"gonum.org/v1/gonum/floats"
|
|
"gonum.org/v1/gonum/integrate/testquad"
|
|
)
|
|
|
|
func TestRomberg(t *testing.T) {
|
|
for i, test := range []struct {
|
|
integral testquad.Integral
|
|
n int
|
|
tol float64
|
|
}{
|
|
{integral: testquad.Constant(0), n: 3, tol: 0},
|
|
{integral: testquad.Constant(0), n: 1<<5 + 1, tol: 0},
|
|
{integral: testquad.Poly(0), n: 3, tol: 1e-14},
|
|
{integral: testquad.Poly(0), n: 1<<5 + 1, tol: 1e-14},
|
|
{integral: testquad.Poly(1), n: 3, tol: 1e-14},
|
|
{integral: testquad.Poly(1), n: 1<<5 + 1, tol: 1e-14},
|
|
{integral: testquad.Poly(2), n: 3, tol: 1e-14},
|
|
{integral: testquad.Poly(2), n: 1<<5 + 1, tol: 1e-14},
|
|
{integral: testquad.Poly(3), n: 3, tol: 1e-14},
|
|
{integral: testquad.Poly(3), n: 1<<5 + 1, tol: 1e-14},
|
|
{integral: testquad.Poly(4), n: 5, tol: 1e-14},
|
|
{integral: testquad.Poly(4), n: 1<<5 + 1, tol: 1e-14},
|
|
{integral: testquad.Poly(5), n: 5, tol: 1e-14},
|
|
{integral: testquad.Poly(5), n: 1<<5 + 1, tol: 1e-14},
|
|
{integral: testquad.Sin(), n: 1<<3 + 1, tol: 1e-10},
|
|
{integral: testquad.Sin(), n: 1<<5 + 1, tol: 1e-14},
|
|
{integral: testquad.XExpMinusX(), n: 1<<3 + 1, tol: 1e-9},
|
|
{integral: testquad.XExpMinusX(), n: 1<<5 + 1, tol: 1e-14},
|
|
{integral: testquad.Sqrt(), n: 1<<10 + 1, tol: 1e-5},
|
|
{integral: testquad.ExpOverX2Plus1(), n: 1<<4 + 1, tol: 1e-7},
|
|
{integral: testquad.ExpOverX2Plus1(), n: 1<<6 + 1, tol: 1e-14},
|
|
} {
|
|
n := test.n
|
|
a := test.integral.A
|
|
b := test.integral.B
|
|
|
|
x := make([]float64, n)
|
|
floats.Span(x, a, b)
|
|
|
|
y := make([]float64, n)
|
|
for i, xi := range x {
|
|
y[i] = test.integral.F(xi)
|
|
}
|
|
|
|
dx := (b - a) / float64(n-1)
|
|
got := Romberg(y, dx)
|
|
|
|
want := test.integral.Value
|
|
diff := math.Abs(got - want)
|
|
if diff > test.tol {
|
|
t.Errorf("Test #%d: %v, n=%v: unexpected result; got=%v want=%v diff=%v",
|
|
i, test.integral.Name, n, got, want, diff)
|
|
}
|
|
}
|
|
}
|