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54 lines
1.0 KiB
Go
54 lines
1.0 KiB
Go
// Copyright ©2016 The gonum Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package testlapack
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import (
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"fmt"
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"math"
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"testing"
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)
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type Dlae2er interface {
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Dlae2(a, b, c float64) (rt1, rt2 float64)
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}
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func Dlae2Test(t *testing.T, impl Dlae2er) {
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for _, test := range []struct {
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a, b, c float64
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}{
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{-10, 5, 3},
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{3, 5, -10},
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{0, 3, 0},
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{1, 3, 1},
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{1, -3, 1},
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{5, 0, 3},
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{3, 0, -5},
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{1, 3, 1.02},
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{1.02, 3, 1},
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{1, -3, -9},
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} {
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a := test.a
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b := test.b
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c := test.c
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rt1, rt2 := impl.Dlae2(a, b, c)
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errStr := fmt.Sprintf("a = %v, b = %v, c = %v", a, b, c)
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// Check if rt1 and rt2 are eigenvalues by checking if det(a - λI) = 0
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a1 := a - rt1
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c1 := c - rt1
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det := a1*c1 - b*b
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if math.Abs(det) > 1e-10 {
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t.Errorf("First eigenvalue mismatch. %s. Det = %v", errStr, det)
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}
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a2 := a - rt2
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c2 := c - rt2
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det = a2*c2 - b*b
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if math.Abs(det) > 1e-10 {
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t.Errorf("Second eigenvalue mismatch. %s. Det = %v", errStr, det)
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}
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}
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}
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