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36 lines
924 B
Go
36 lines
924 B
Go
// Copyright ©2017 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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//+build !go1.8 !amd64 noasm appengine
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package f64
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// Ger performs the rank-one operation
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// A += alpha * x * y^T
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// where A is an m×n dense matrix, x and y are vectors, and alpha is a scalar.
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func Ger(m, n uintptr, alpha float64, x []float64, incX uintptr, y []float64, incY uintptr, a []float64, lda uintptr) {
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if incX == 1 && incY == 1 {
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x = x[:m]
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y = y[:n]
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for i, xv := range x {
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AxpyUnitary(alpha*xv, y, a[uintptr(i)*lda:uintptr(i)*lda+n])
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}
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return
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}
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var ky, kx uintptr
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if int(incY) < 0 {
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ky = uintptr(-int(n-1) * int(incY))
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}
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if int(incX) < 0 {
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kx = uintptr(-int(m-1) * int(incX))
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}
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ix := kx
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for i := 0; i < int(m); i++ {
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AxpyInc(alpha*x[ix], y, a[uintptr(i)*lda:uintptr(i)*lda+n], n, incY, 1, ky, 0)
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ix += incX
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}
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}
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