+++ /dev/null
-// 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
-
-import (
- "gonum.org/v1/gonum/blas"
- "gonum.org/v1/gonum/blas/blas64"
-)
-
-// Dtrti2 computes the inverse of a triangular matrix, storing the result in place
-// into a. This is the BLAS level 2 version of the algorithm.
-//
-// Dtrti2 is an internal routine. It is exported for testing purposes.
-func (impl Implementation) Dtrti2(uplo blas.Uplo, diag blas.Diag, n int, a []float64, lda int) {
- checkMatrix(n, n, a, lda)
- if uplo != blas.Upper && uplo != blas.Lower {
- panic(badUplo)
- }
- if diag != blas.NonUnit && diag != blas.Unit {
- panic(badDiag)
- }
- bi := blas64.Implementation()
-
- nonUnit := diag == blas.NonUnit
- // TODO(btracey): Replace this with a row-major ordering.
- if uplo == blas.Upper {
- for j := 0; j < n; j++ {
- var ajj float64
- if nonUnit {
- ajj = 1 / a[j*lda+j]
- a[j*lda+j] = ajj
- ajj *= -1
- } else {
- ajj = -1
- }
- bi.Dtrmv(blas.Upper, blas.NoTrans, diag, j, a, lda, a[j:], lda)
- bi.Dscal(j, ajj, a[j:], lda)
- }
- return
- }
- for j := n - 1; j >= 0; j-- {
- var ajj float64
- if nonUnit {
- ajj = 1 / a[j*lda+j]
- a[j*lda+j] = ajj
- ajj *= -1
- } else {
- ajj = -1
- }
- if j < n-1 {
- bi.Dtrmv(blas.Lower, blas.NoTrans, diag, n-j-1, a[(j+1)*lda+j+1:], lda, a[(j+1)*lda+j:], lda)
- bi.Dscal(n-j-1, ajj, a[(j+1)*lda+j:], lda)
- }
- }
-}