sgbmv.f.html
来自「famous linear algebra library (LAPACK) p」· HTML 代码 · 共 322 行 · 第 1/2 页
HTML
322 行
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>sgbmv.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="SGBMV.1"></a><a href="sgbmv.f.html#SGBMV.1">SGBMV</a>(TRANS,M,N,KL,KU,ALPHA,A,LDA,X,INCX,BETA,Y,INCY)
<span class="comment">*</span><span class="comment"> .. Scalar Arguments ..
</span> REAL ALPHA,BETA
INTEGER INCX,INCY,KL,KU,LDA,M,N
CHARACTER TRANS
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Array Arguments ..
</span> REAL A(LDA,*),X(*),Y(*)
<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="SGBMV.14"></a><a href="sgbmv.f.html#SGBMV.1">SGBMV</a> performs one of the matrix-vector operations
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> y := alpha*A*x + beta*y, or y := alpha*A'*x + beta*y,
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> where alpha and beta are scalars, x and y are vectors and A is an
</span><span class="comment">*</span><span class="comment"> m by n band matrix, with kl sub-diagonals and ku super-diagonals.
</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"> TRANS - CHARACTER*1.
</span><span class="comment">*</span><span class="comment"> On entry, TRANS specifies the operation to be performed as
</span><span class="comment">*</span><span class="comment"> follows:
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> TRANS = 'N' or 'n' y := alpha*A*x + beta*y.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> TRANS = 'T' or 't' y := alpha*A'*x + beta*y.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> TRANS = 'C' or 'c' y := alpha*A'*x + beta*y.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> M - INTEGER.
</span><span class="comment">*</span><span class="comment"> On entry, M specifies the number of rows of the matrix A.
</span><span class="comment">*</span><span class="comment"> M must be at least zero.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> N - INTEGER.
</span><span class="comment">*</span><span class="comment"> On entry, N specifies the number of columns of the matrix A.
</span><span class="comment">*</span><span class="comment"> N must be at least zero.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> KL - INTEGER.
</span><span class="comment">*</span><span class="comment"> On entry, KL specifies the number of sub-diagonals of the
</span><span class="comment">*</span><span class="comment"> matrix A. KL must satisfy 0 .le. KL.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> KU - INTEGER.
</span><span class="comment">*</span><span class="comment"> On entry, KU specifies the number of super-diagonals of the
</span><span class="comment">*</span><span class="comment"> matrix A. KU must satisfy 0 .le. KU.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> ALPHA - REAL .
</span><span class="comment">*</span><span class="comment"> On entry, ALPHA specifies the scalar alpha.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> A - REAL array of DIMENSION ( LDA, n ).
</span><span class="comment">*</span><span class="comment"> Before entry, the leading ( kl + ku + 1 ) by n part of the
</span><span class="comment">*</span><span class="comment"> array A must contain the matrix of coefficients, supplied
</span><span class="comment">*</span><span class="comment"> column by column, with the leading diagonal of the matrix in
</span><span class="comment">*</span><span class="comment"> row ( ku + 1 ) of the array, the first super-diagonal
</span><span class="comment">*</span><span class="comment"> starting at position 2 in row ku, the first sub-diagonal
</span><span class="comment">*</span><span class="comment"> starting at position 1 in row ( ku + 2 ), and so on.
</span><span class="comment">*</span><span class="comment"> Elements in the array A that do not correspond to elements
</span><span class="comment">*</span><span class="comment"> in the band matrix (such as the top left ku by ku triangle)
</span><span class="comment">*</span><span class="comment"> are not referenced.
</span><span class="comment">*</span><span class="comment"> The following program segment will transfer a band matrix
</span><span class="comment">*</span><span class="comment"> from conventional full matrix storage to band storage:
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> DO 20, J = 1, N
</span><span class="comment">*</span><span class="comment"> K = KU + 1 - J
</span><span class="comment">*</span><span class="comment"> DO 10, I = MAX( 1, J - KU ), MIN( M, J + KL )
</span><span class="comment">*</span><span class="comment"> A( K + I, J ) = matrix( I, J )
</span><span class="comment">*</span><span class="comment"> 10 CONTINUE
</span><span class="comment">*</span><span class="comment"> 20 CONTINUE
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> LDA - INTEGER.
</span><span class="comment">*</span><span class="comment"> On entry, LDA specifies the first dimension of A as declared
</span><span class="comment">*</span><span class="comment"> in the calling (sub) program. LDA must be at least
</span><span class="comment">*</span><span class="comment"> ( kl + ku + 1 ).
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> X - REAL array of DIMENSION at least
</span><span class="comment">*</span><span class="comment"> ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n'
</span><span class="comment">*</span><span class="comment"> and at least
</span><span class="comment">*</span><span class="comment"> ( 1 + ( m - 1 )*abs( INCX ) ) otherwise.
</span><span class="comment">*</span><span class="comment"> Before entry, the incremented array X must contain the
</span><span class="comment">*</span><span class="comment"> vector x.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> INCX - INTEGER.
</span><span class="comment">*</span><span class="comment"> On entry, INCX specifies the increment for the elements of
</span><span class="comment">*</span><span class="comment"> X. INCX must not be zero.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> BETA - REAL .
</span><span class="comment">*</span><span class="comment"> On entry, BETA specifies the scalar beta. When BETA is
</span><span class="comment">*</span><span class="comment"> supplied as zero then Y need not be set on input.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Y - REAL array of DIMENSION at least
</span><span class="comment">*</span><span class="comment"> ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n'
</span><span class="comment">*</span><span class="comment"> and at least
</span><span class="comment">*</span><span class="comment"> ( 1 + ( n - 1 )*abs( INCY ) ) otherwise.
</span><span class="comment">*</span><span class="comment"> Before entry, the incremented array Y must contain the
</span><span class="comment">*</span><span class="comment"> vector y. On exit, Y is overwritten by the updated vector y.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> INCY - INTEGER.
</span><span class="comment">*</span><span class="comment"> On entry, INCY specifies the increment for the elements of
</span><span class="comment">*</span><span class="comment"> Y. INCY must not be zero.
</span><span class="comment">*</span><span class="comment"> Unchanged on exit.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> Level 2 Blas routine.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> -- Written on 22-October-1986.
</span><span class="comment">*</span><span class="comment"> Jack Dongarra, Argonne National Lab.
</span><span class="comment">*</span><span class="comment"> Jeremy Du Croz, Nag Central Office.
</span><span class="comment">*</span><span class="comment"> Sven Hammarling, Nag Central Office.
</span><span class="comment">*</span><span class="comment"> Richard Hanson, Sandia National Labs.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> .. Parameters ..
</span> REAL ONE,ZERO
PARAMETER (ONE=1.0E+0,ZERO=0.0E+0)
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Local Scalars ..
</span> REAL TEMP
INTEGER I,INFO,IX,IY,J,JX,JY,K,KUP1,KX,KY,LENX,LENY
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. External Functions ..
</span> LOGICAL <a name="LSAME.136"></a><a href="lsame.f.html#LSAME.1">LSAME</a>
EXTERNAL <a name="LSAME.137"></a><a href="lsame.f.html#LSAME.1">LSAME</a>
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. External Subroutines ..
</span> EXTERNAL <a name="XERBLA.140"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>
<span class="comment">*</span><span class="comment"> ..
</span><span class="comment">*</span><span class="comment"> .. Intrinsic Functions ..
⌨️ 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?