lapack: imported lapack as a subtree

lapack/testlapack/dlas2.go

@@ -0,0 +1,34 @@
+// Copyright ©2015 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"
+	"testing"
+)
+
+type Dlas2er interface {
+	Dlas2(f, g, h float64) (min, max float64)
+}
+
+func Dlas2Test(t *testing.T, impl Dlas2er) {
+	for i, test := range []struct {
+		f, g, h, ssmin, ssmax float64
+	}{
+		// Singular values computed from Octave.
+		{10, 30, 12, 3.567778859365365, 33.634371616111189},
+		{10, 30, -12, 3.567778859365365, 33.634371616111189},
+		{2, 30, -12, 0.741557056404952, 32.364333658088754},
+		{-2, 5, 12, 1.842864429909778, 13.023204317408728},
+	} {
+		ssmin, ssmax := impl.Dlas2(test.f, test.g, test.h)
+		if math.Abs(ssmin-test.ssmin) > 1e-12 {
+			t.Errorf("Case %d, minimal singular value mismatch. Want %v, got %v", i, test.ssmin, ssmin)
+		}
+		if math.Abs(ssmax-test.ssmax) > 1e-12 {
+			t.Errorf("Case %d, minimal singular value mismatch. Want %v, got %v", i, test.ssmin, ssmin)
+		}
+	}
+}