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59 lines
1.3 KiB
Go
59 lines
1.3 KiB
Go
// Copyright ©2015 The Gonum Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package gonum
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import "gonum.org/v1/gonum/blas"
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// Dlaset sets the off-diagonal elements of A to alpha, and the diagonal
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// elements to beta. If uplo == blas.Upper, only the elements in the upper
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// triangular part are set. If uplo == blas.Lower, only the elements in the
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// lower triangular part are set. If uplo is otherwise, all of the elements of A
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// are set.
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//
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// Dlaset is an internal routine. It is exported for testing purposes.
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func (impl Implementation) Dlaset(uplo blas.Uplo, m, n int, alpha, beta float64, a []float64, lda int) {
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switch {
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case m < 0:
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panic(mLT0)
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case n < 0:
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panic(nLT0)
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case lda < max(1, n):
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panic(badLdA)
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}
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minmn := min(m, n)
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if minmn == 0 {
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return
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}
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if len(a) < (m-1)*lda+n {
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panic(shortA)
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}
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switch uplo {
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case blas.Upper:
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for i := 0; i < m; i++ {
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for j := i + 1; j < n; j++ {
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a[i*lda+j] = alpha
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}
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}
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case blas.Lower:
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for i := 0; i < m; i++ {
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for j := 0; j < min(i, n); j++ {
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a[i*lda+j] = alpha
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}
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}
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default:
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for i := 0; i < m; i++ {
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for j := 0; j < n; j++ {
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a[i*lda+j] = alpha
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}
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}
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}
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for i := 0; i < minmn; i++ {
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a[i*lda+i] = beta
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}
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}
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