lapack: imported lapack as a subtree

lapack/testlapack/dorg2l.go

@@ -0,0 +1,75 @@
+// Copyright ©2016 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 testlapack
+
+import (
+	"math"
+	"math/rand"
+	"testing"
+
+	"github.com/gonum/blas/blas64"
+)
+
+type Dorg2ler interface {
+	Dorg2l(m, n, k int, a []float64, lda int, tau, work []float64)
+	Dgeql2er
+}
+
+func Dorg2lTest(t *testing.T, impl Dorg2ler) {
+	rnd := rand.New(rand.NewSource(1))
+	for _, test := range []struct {
+		m, n, k, lda int
+	}{
+		{5, 4, 3, 0},
+		{5, 4, 4, 0},
+		{3, 3, 2, 0},
+		{5, 5, 5, 0},
+	} {
+		m := test.m
+		n := test.n
+		k := test.k
+		lda := test.lda
+		if lda == 0 {
+			lda = n
+		}
+
+		a := make([]float64, m*lda)
+		for i := range a {
+			a[i] = rnd.NormFloat64()
+		}
+		tau := nanSlice(max(m, n))
+		work := make([]float64, n)
+		impl.Dgeql2(m, n, a, lda, tau, work)
+
+		aCopy := make([]float64, len(a))
+		copy(aCopy, a)
+		impl.Dorg2l(m, n, k, a, lda, tau[n-k:], work)
+		if !hasOrthonormalColumns(m, n, a, lda) {
+			t.Errorf("Q is not orthonormal. m = %v, n = %v, k = %v", m, n, k)
+		}
+	}
+}
+
+// hasOrthornormalColumns checks that the columns of a are orthonormal.
+func hasOrthonormalColumns(m, n int, a []float64, lda int) bool {
+	for i := 0; i < n; i++ {
+		for j := i; j < n; j++ {
+			dot := blas64.Dot(m,
+				blas64.Vector{Inc: lda, Data: a[i:]},
+				blas64.Vector{Inc: lda, Data: a[j:]},
+			)
+			if i == j {
+				if math.Abs(dot-1) > 1e-10 {
+					return false
+				}
+			} else {
+				if math.Abs(dot) > 1e-10 {
+					return false
+				}
+			}
+		}
+	}
+	return true
+}