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120 lines
2.9 KiB
Go
120 lines
2.9 KiB
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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//go:build !amd64 || noasm || gccgo || safe
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// +build !amd64 noasm gccgo safe
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package f64
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// Ger performs the rank-one operation
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// A += alpha * x * yᵀ
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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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// GemvN computes
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// y = alpha * A * x + beta * y
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// where A is an m×n dense matrix, x and y are vectors, and alpha and beta are scalars.
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func GemvN(m, n uintptr, alpha float64, a []float64, lda uintptr, x []float64, incX uintptr, beta float64, y []float64, incY uintptr) {
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var kx, ky, i uintptr
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if int(incX) < 0 {
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kx = uintptr(-int(n-1) * int(incX))
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}
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if int(incY) < 0 {
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ky = uintptr(-int(m-1) * int(incY))
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}
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if incX == 1 && incY == 1 {
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if beta == 0 {
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for i = 0; i < m; i++ {
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y[i] = alpha * DotUnitary(a[lda*i:lda*i+n], x)
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}
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return
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}
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for i = 0; i < m; i++ {
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y[i] = y[i]*beta + alpha*DotUnitary(a[lda*i:lda*i+n], x)
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}
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return
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}
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iy := ky
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if beta == 0 {
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for i = 0; i < m; i++ {
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y[iy] = alpha * DotInc(x, a[lda*i:lda*i+n], n, incX, 1, kx, 0)
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iy += incY
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}
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return
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}
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for i = 0; i < m; i++ {
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y[iy] = y[iy]*beta + alpha*DotInc(x, a[lda*i:lda*i+n], n, incX, 1, kx, 0)
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iy += incY
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}
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}
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// GemvT computes
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// y = alpha * Aᵀ * x + beta * y
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// where A is an m×n dense matrix, x and y are vectors, and alpha and beta are scalars.
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func GemvT(m, n uintptr, alpha float64, a []float64, lda uintptr, x []float64, incX uintptr, beta float64, y []float64, incY uintptr) {
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var kx, ky, i uintptr
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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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if int(incY) < 0 {
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ky = uintptr(-int(n-1) * int(incY))
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}
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switch {
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case beta == 0: // beta == 0 is special-cased to memclear
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if incY == 1 {
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for i := range y {
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y[i] = 0
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}
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} else {
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iy := ky
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for i := 0; i < int(n); i++ {
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y[iy] = 0
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iy += incY
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}
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}
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case int(incY) < 0:
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ScalInc(beta, y, n, uintptr(int(-incY)))
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case incY == 1:
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ScalUnitary(beta, y[:n])
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default:
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ScalInc(beta, y, n, incY)
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}
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if incX == 1 && incY == 1 {
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for i = 0; i < m; i++ {
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AxpyUnitaryTo(y, alpha*x[i], a[lda*i:lda*i+n], y)
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}
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return
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}
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ix := kx
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for i = 0; i < m; i++ {
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AxpyInc(alpha*x[ix], a[lda*i:lda*i+n], y, n, 1, incY, 0, ky)
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ix += incX
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}
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}
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