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50 lines
1.1 KiB
Go
50 lines
1.1 KiB
Go
// Copyright ©2019 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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"math"
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"testing"
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"golang.org/x/exp/rand"
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)
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type Dcombssqer interface {
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Dcombssq(scale1, ssq1, scale2, ssq2 float64) (scale, ssq float64)
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}
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func DcombssqTest(t *testing.T, impl Dcombssqer) {
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const tol = 1e-15
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rnd := rand.New(rand.NewSource(1))
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for i := 0; i < 10; i++ {
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// Generate random, non-negative input.
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scale1 := rnd.Float64()
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ssq1 := rnd.Float64()
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scale2 := rnd.Float64()
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ssq2 := rnd.Float64()
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switch i {
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case 0:
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scale1 = 0
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case 1:
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scale2 = 0
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case 2:
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scale1, scale2 = 0, 0
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}
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// Compute scale and ssq such that
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// scale^2 * ssq := scale1^2 * ssq1 + scale2^2 * ssq2
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scale, ssq := impl.Dcombssq(scale1, ssq1, scale2, ssq2)
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// Compute the expected result in a non-sophisticated way and
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// compare against the result we got.
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want := scale1*scale1*ssq1 + scale2*scale2*ssq2
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got := scale * scale * ssq
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if math.Abs(want-got) >= tol {
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t.Errorf("Case %v: unexpected result; got %v, want %v", i, got, want)
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}
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}
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}
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