zlaqps.f.html
来自「famous linear algebra library (LAPACK) p」· HTML 代码 · 共 291 行 · 第 1/2 页
HTML
291 行
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>zlaqps.f</title>
<meta name="generator" content="emacs 21.3.1; htmlfontify 0.20">
<style type="text/css"><!--
body { background: rgb(255, 255, 255); color: rgb(0, 0, 0); font-style: normal; font-weight: 500; font-stretch: normal; font-family: adobe-courier; font-size: 11pt; text-decoration: none; }
span.default { background: rgb(255, 255, 255); color: rgb(0, 0, 0); font-style: normal; font-weight: 500; font-stretch: normal; font-family: adobe-courier; font-size: 11pt; text-decoration: none; }
span.default a { background: rgb(255, 255, 255); color: rgb(0, 0, 0); font-style: normal; font-weight: 500; font-stretch: normal; font-family: adobe-courier; font-size: 11pt; text-decoration: underline; }
span.string { color: rgb(188, 143, 143); background: rgb(255, 255, 255); font-style: normal; font-weight: 500; font-stretch: normal; font-family: adobe-courier; font-size: 11pt; text-decoration: none; }
span.string a { color: rgb(188, 143, 143); background: rgb(255, 255, 255); font-style: normal; font-weight: 500; font-stretch: normal; font-family: adobe-courier; font-size: 11pt; text-decoration: underline; }
span.comment { color: rgb(178, 34, 34); background: rgb(255, 255, 255); font-style: normal; font-weight: 500; font-stretch: normal; font-family: adobe-courier; font-size: 11pt; text-decoration: none; }
span.comment a { color: rgb(178, 34, 34); background: rgb(255, 255, 255); font-style: normal; font-weight: 500; font-stretch: normal; font-family: adobe-courier; font-size: 11pt; text-decoration: underline; }
--></style>
</head>
<body>
<pre>
SUBROUTINE <a name="ZLAQPS.1"></a><a href="zlaqps.f.html#ZLAQPS.1">ZLAQPS</a>( M, N, OFFSET, NB, KB, A, LDA, JPVT, TAU, VN1,
$ VN2, AUXV, F, LDF )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> -- LAPACK auxiliary routine (version 3.1) --
</span><span class="comment">*</span><span class="comment"> Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
</span><span class="comment">*</span><span class="comment"> November 2006
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> .. Scalar Arguments ..
</span> INTEGER KB, LDA, LDF, M, N, NB, OFFSET
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Array Arguments ..
</span> INTEGER JPVT( * )
DOUBLE PRECISION VN1( * ), VN2( * )
COMPLEX*16 A( LDA, * ), AUXV( * ), F( LDF, * ), TAU( * )
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Purpose
</span><span class="comment">*</span><span class="comment"> =======
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> <a name="ZLAQPS.20"></a><a href="zlaqps.f.html#ZLAQPS.1">ZLAQPS</a> computes a step of QR factorization with column pivoting
</span><span class="comment">*</span><span class="comment"> of a complex M-by-N matrix A by using Blas-3. It tries to factorize
</span><span class="comment">*</span><span class="comment"> NB columns from A starting from the row OFFSET+1, and updates all
</span><span class="comment">*</span><span class="comment"> of the matrix with Blas-3 xGEMM.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> In some cases, due to catastrophic cancellations, it cannot
</span><span class="comment">*</span><span class="comment"> factorize NB columns. Hence, the actual number of factorized
</span><span class="comment">*</span><span class="comment"> columns is returned in KB.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Block A(1:OFFSET,1:N) is accordingly pivoted, but not factorized.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Arguments
</span><span class="comment">*</span><span class="comment"> =========
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> M (input) INTEGER
</span><span class="comment">*</span><span class="comment"> The number of rows of the matrix A. M >= 0.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> N (input) INTEGER
</span><span class="comment">*</span><span class="comment"> The number of columns of the matrix A. N >= 0
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> OFFSET (input) INTEGER
</span><span class="comment">*</span><span class="comment"> The number of rows of A that have been factorized in
</span><span class="comment">*</span><span class="comment"> previous steps.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> NB (input) INTEGER
</span><span class="comment">*</span><span class="comment"> The number of columns to factorize.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> KB (output) INTEGER
</span><span class="comment">*</span><span class="comment"> The number of columns actually factorized.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> A (input/output) COMPLEX*16 array, dimension (LDA,N)
</span><span class="comment">*</span><span class="comment"> On entry, the M-by-N matrix A.
</span><span class="comment">*</span><span class="comment"> On exit, block A(OFFSET+1:M,1:KB) is the triangular
</span><span class="comment">*</span><span class="comment"> factor obtained and block A(1:OFFSET,1:N) has been
</span><span class="comment">*</span><span class="comment"> accordingly pivoted, but no factorized.
</span><span class="comment">*</span><span class="comment"> The rest of the matrix, block A(OFFSET+1:M,KB+1:N) has
</span><span class="comment">*</span><span class="comment"> been updated.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> LDA (input) INTEGER
</span><span class="comment">*</span><span class="comment"> The leading dimension of the array A. LDA >= max(1,M).
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> JPVT (input/output) INTEGER array, dimension (N)
</span><span class="comment">*</span><span class="comment"> JPVT(I) = K <==> Column K of the full matrix A has been
</span><span class="comment">*</span><span class="comment"> permuted into position I in AP.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> TAU (output) COMPLEX*16 array, dimension (KB)
</span><span class="comment">*</span><span class="comment"> The scalar factors of the elementary reflectors.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> VN1 (input/output) DOUBLE PRECISION array, dimension (N)
</span><span class="comment">*</span><span class="comment"> The vector with the partial column norms.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> VN2 (input/output) DOUBLE PRECISION array, dimension (N)
</span><span class="comment">*</span><span class="comment"> The vector with the exact column norms.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> AUXV (input/output) COMPLEX*16 array, dimension (NB)
</span><span class="comment">*</span><span class="comment"> Auxiliar vector.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> F (input/output) COMPLEX*16 array, dimension (LDF,NB)
</span><span class="comment">*</span><span class="comment"> Matrix F' = L*Y'*A.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> LDF (input) INTEGER
</span><span class="comment">*</span><span class="comment"> The leading dimension of the array F. LDF >= max(1,N).
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Further Details
</span><span class="comment">*</span><span class="comment"> ===============
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Based on contributions by
</span><span class="comment">*</span><span class="comment"> G. Quintana-Orti, Depto. de Informatica, Universidad Jaime I, Spain
</span><span class="comment">*</span><span class="comment"> X. Sun, Computer Science Dept., Duke University, USA
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> =====================================================================
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> .. Parameters ..
</span> DOUBLE PRECISION ZERO, ONE
COMPLEX*16 CZERO, CONE
PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0,
$ CZERO = ( 0.0D+0, 0.0D+0 ),
$ CONE = ( 1.0D+0, 0.0D+0 ) )
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Local Scalars ..
</span> INTEGER ITEMP, J, K, LASTRK, LSTICC, PVT, RK
DOUBLE PRECISION TEMP, TEMP2, TOL3Z
COMPLEX*16 AKK
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. External Subroutines ..
</span> EXTERNAL ZGEMM, ZGEMV, <a name="ZLARFG.105"></a><a href="zlarfg.f.html#ZLARFG.1">ZLARFG</a>, ZSWAP
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Intrinsic Functions ..
</span> INTRINSIC ABS, DBLE, DCONJG, MAX, MIN, NINT, SQRT
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. External Functions ..
</span> INTEGER IDAMAX
DOUBLE PRECISION <a name="DLAMCH.112"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a>, DZNRM2
EXTERNAL IDAMAX, <a name="DLAMCH.113"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a>, DZNRM2
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Executable Statements ..
</span><span class="comment">*</span><span class="comment">
</span> LASTRK = MIN( M, N+OFFSET )
LSTICC = 0
K = 0
TOL3Z = SQRT(<a name="DLAMCH.120"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a>(<span class="string">'Epsilon'</span>))
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Beginning of while loop.
</span><span class="comment">*</span><span class="comment">
</span> 10 CONTINUE
IF( ( K.LT.NB ) .AND. ( LSTICC.EQ.0 ) ) THEN
K = K + 1
RK = OFFSET + K
⌨️ 快捷键说明
复制代码Ctrl + C
搜索代码Ctrl + F
全屏模式F11
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?