Add Dlasrt

lapack.go

@@ -50,6 +50,14 @@ const (
 	Backward Direct = 'B' // Reflectors are left-multiplied, H_k * ... * H_2 * H_1
 )
 
+// Sort is the sorting order.
+type Sort byte
+
+const (
+	SortIncreasing Sort = 'I'
+	SortDecreasing Sort = 'D'
+)
+
 // StoreV indicates the storage direction of elementary reflectors.
 type StoreV byte
 

native/dlasrt.go

@@ -0,0 +1,27 @@
+// 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 native
+
+import (
+	"sort"
+
+	"github.com/gonum/lapack"
+)
+
+// Dlasrt sorts the numbers in the input slice d. If sort == lapack.SortIncreasing,
+// the elements are sorted in increasing order. If sort == lapack.SortDecreasing,
+// the elements are sorted in decreasing order.
+func (impl Implementation) Dlasrt(s lapack.Sort, n int, d []float64) {
+	checkVector(n, d, 1)
+	d = d[:n]
+	switch s {
+	default:
+		panic("lapack: bad sort")
+	case lapack.SortIncreasing:
+		sort.Sort(sort.Reverse(sort.Float64Slice(d)))
+	case lapack.SortDecreasing:
+		sort.Float64s(d)
+	}
+}