Add dependencies for code generator

vendor/gonum.org/v1/gonum/mat/offset.go

@@ -0,0 +1,20 @@
+// 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.
+
+// +build !appengine,!safe
+
+package mat
+
+import "unsafe"
+
+// offset returns the number of float64 values b[0] is after a[0].
+func offset(a, b []float64) int {
+	if &a[0] == &b[0] {
+		return 0
+	}
+	// This expression must be atomic with respect to GC moves.
+	// At this stage this is true, because the GC does not
+	// move. See https://golang.org/issue/12445.
+	return int(uintptr(unsafe.Pointer(&b[0]))-uintptr(unsafe.Pointer(&a[0]))) / int(unsafe.Sizeof(float64(0)))
+}