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929014505b
Reorder vector and matrix struct fields to match the order in which BLAS routines accept them. This makes calls with inline declarations with unnamed fields consistent and easier to understand.
74 lines
1.7 KiB
Go
74 lines
1.7 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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"math"
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"testing"
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"golang.org/x/exp/rand"
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"gonum.org/v1/gonum/blas"
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"gonum.org/v1/gonum/blas/blas64"
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)
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type Dlacn2er interface {
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Dlacn2(n int, v, x []float64, isgn []int, est float64, kase int, isave *[3]int) (float64, int)
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}
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func Dlacn2Test(t *testing.T, impl Dlacn2er) {
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rnd := rand.New(rand.NewSource(1))
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for _, n := range []int{1, 2, 3, 4, 5, 7, 10, 15, 20, 100} {
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for cas := 0; cas < 10; cas++ {
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a := randomGeneral(n, n, n, rnd)
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// Compute the 1-norm of A explicitly.
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var norm1 float64
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for j := 0; j < n; j++ {
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var sum float64
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for i := 0; i < n; i++ {
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sum += math.Abs(a.Data[i*a.Stride+j])
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}
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if sum > norm1 {
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norm1 = sum
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}
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}
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// Compute the estimate of 1-norm using Dlanc2.
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x := make([]float64, n)
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work := make([]float64, n)
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v := make([]float64, n)
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isgn := make([]int, n)
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var (
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kase int
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isave [3]int
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got float64
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)
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loop:
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for {
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got, kase = impl.Dlacn2(n, v, x, isgn, got, kase, &isave)
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switch kase {
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default:
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panic("Dlacn2 returned invalid value of kase")
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case 0:
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break loop
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case 1:
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blas64.Gemv(blas.NoTrans, 1, a, blas64.Vector{x, 1}, 0, blas64.Vector{work, 1})
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copy(x, work)
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case 2:
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blas64.Gemv(blas.Trans, 1, a, blas64.Vector{x, 1}, 0, blas64.Vector{work, 1})
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copy(x, work)
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}
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}
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// Check that got is either accurate enough or a
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// lower estimate of the 1-norm of A.
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if math.Abs(got-norm1) > 1e-8 && got > norm1 {
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t.Errorf("Case n=%v: not lower estimate. 1-norm %v, estimate %v", n, norm1, got)
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}
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}
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}
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}
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