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[bytom/vapor.git] / vendor / gonum.org / v1 / gonum / lapack / gonum / iladlr.go

diff --git a/vendor/gonum.org/v1/gonum/lapack/gonum/iladlr.go b/vendor/gonum.org/v1/gonum/lapack/gonum/iladlr.go
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+++ b/vendor/gonum.org/v1/gonum/lapack/gonum/iladlr.go
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+// 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 gonum
+
+// Iladlr scans a matrix for its last non-zero row. Returns -1 if the matrix
+// is all zeros.
+//
+// Iladlr is an internal routine. It is exported for testing purposes.
+func (Implementation) Iladlr(m, n int, a []float64, lda int) int {
+       if m == 0 {
+               return m - 1
+       }
+
+       checkMatrix(m, n, a, lda)
+
+       // Check the common case where the corner is non-zero
+       if a[(m-1)*lda] != 0 || a[(m-1)*lda+n-1] != 0 {
+               return m - 1
+       }
+       for i := m - 1; i >= 0; i-- {
+               for j := 0; j < n; j++ {
+                       if a[i*lda+j] != 0 {
+                               return i
+                       }
+               }
+       }
+       return -1
+}