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ec100cf00f
Improved function documentation Fixed dlarfb and dlarft and added full tests Added dgelq2 Working Dgels Fix many comments and tests Many PR comment responses Responded to more PR comments Many PR comments
30 lines
904 B
Go
30 lines
904 B
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 native
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import "math"
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// Dlassq updates a sum of squares in scaled form. The input parameters scale and
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// sumsq represent the current scale and total sum of squares. These values are
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// updated with the information in the first n elements of the vector specified
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// by x and incX.
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func (impl Implementation) Dlassq(n int, x []float64, incx int, scale float64, sumsq float64) (scl, smsq float64) {
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if n <= 0 {
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return scale, sumsq
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}
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for ix := 0; ix <= (n-1)*incx; ix += incx {
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absxi := math.Abs(x[ix])
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if absxi > 0 || math.IsNaN(absxi) {
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if scale < absxi {
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sumsq = 1 + sumsq*(scale/absxi)*(scale/absxi)
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scale = absxi
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} else {
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sumsq += (absxi / scale) * (absxi / scale)
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}
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}
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}
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return scale, sumsq
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}
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