zlangt.f.html

来自「famous linear algebra library (LAPACK) p」· HTML 代码 · 共 166 行

HTML
166 行
字号 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
  <title>zlangt.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>
      DOUBLE PRECISION FUNCTION <a name="ZLANGT.1"></a><a href="zlangt.f.html#ZLANGT.1">ZLANGT</a>( NORM, N, DL, D, DU )
<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>      CHARACTER          NORM
      INTEGER            N
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Array Arguments ..
</span>      COMPLEX*16         D( * ), DL( * ), DU( * )
<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="ZLANGT.18"></a><a href="zlangt.f.html#ZLANGT.1">ZLANGT</a>  returns the value of the one norm,  or the Frobenius norm, or
</span><span class="comment">*</span><span class="comment">  the  infinity norm,  or the  element of  largest absolute value  of a
</span><span class="comment">*</span><span class="comment">  complex tridiagonal matrix A.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  Description
</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="ZLANGT.25"></a><a href="zlangt.f.html#ZLANGT.1">ZLANGT</a> returns the value
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     <a name="ZLANGT.27"></a><a href="zlangt.f.html#ZLANGT.1">ZLANGT</a> = ( max(abs(A(i,j))), NORM = 'M' or 'm'
</span><span class="comment">*</span><span class="comment">              (
</span><span class="comment">*</span><span class="comment">              ( norm1(A),         NORM = '1', 'O' or 'o'
</span><span class="comment">*</span><span class="comment">              (
</span><span class="comment">*</span><span class="comment">              ( normI(A),         NORM = 'I' or 'i'
</span><span class="comment">*</span><span class="comment">              (
</span><span class="comment">*</span><span class="comment">              ( normF(A),         NORM = 'F', 'f', 'E' or 'e'
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  where  norm1  denotes the  one norm of a matrix (maximum column sum),
</span><span class="comment">*</span><span class="comment">  normI  denotes the  infinity norm  of a matrix  (maximum row sum) and
</span><span class="comment">*</span><span class="comment">  normF  denotes the  Frobenius norm of a matrix (square root of sum of
</span><span class="comment">*</span><span class="comment">  squares).  Note that  max(abs(A(i,j)))  is not a consistent matrix norm.
</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">  NORM    (input) CHARACTER*1
</span><span class="comment">*</span><span class="comment">          Specifies the value to be returned in <a name="ZLANGT.44"></a><a href="zlangt.f.html#ZLANGT.1">ZLANGT</a> as described
</span><span class="comment">*</span><span class="comment">          above.
</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 order of the matrix A.  N &gt;= 0.  When N = 0, <a name="ZLANGT.48"></a><a href="zlangt.f.html#ZLANGT.1">ZLANGT</a> is
</span><span class="comment">*</span><span class="comment">          set to zero.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  DL      (input) COMPLEX*16 array, dimension (N-1)
</span><span class="comment">*</span><span class="comment">          The (n-1) sub-diagonal elements of A.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  D       (input) COMPLEX*16 array, dimension (N)
</span><span class="comment">*</span><span class="comment">          The diagonal elements of A.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  DU      (input) COMPLEX*16 array, dimension (N-1)
</span><span class="comment">*</span><span class="comment">          The (n-1) super-diagonal elements of A.
</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   ONE, ZERO
      PARAMETER          ( ONE = 1.0D+0, ZERO = 0.0D+0 )
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Local Scalars ..
</span>      INTEGER            I
      DOUBLE PRECISION   ANORM, SCALE, SUM
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. External Functions ..
</span>      LOGICAL            <a name="LSAME.71"></a><a href="lsame.f.html#LSAME.1">LSAME</a>
      EXTERNAL           <a name="LSAME.72"></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="ZLASSQ.75"></a><a href="zlassq.f.html#ZLASSQ.1">ZLASSQ</a>
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Intrinsic Functions ..
</span>      INTRINSIC          ABS, MAX, SQRT
<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>      IF( N.LE.0 ) THEN
         ANORM = ZERO
      ELSE IF( <a name="LSAME.84"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( NORM, <span class="string">'M'</span> ) ) THEN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">        Find max(abs(A(i,j))).
</span><span class="comment">*</span><span class="comment">
</span>         ANORM = ABS( D( N ) )
         DO 10 I = 1, N - 1
            ANORM = MAX( ANORM, ABS( DL( I ) ) )
            ANORM = MAX( ANORM, ABS( D( I ) ) )
            ANORM = MAX( ANORM, ABS( DU( I ) ) )
   10    CONTINUE
      ELSE IF( <a name="LSAME.94"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( NORM, <span class="string">'O'</span> ) .OR. NORM.EQ.<span class="string">'1'</span> ) THEN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">        Find norm1(A).
</span><span class="comment">*</span><span class="comment">
</span>         IF( N.EQ.1 ) THEN
            ANORM = ABS( D( 1 ) )
         ELSE
            ANORM = MAX( ABS( D( 1 ) )+ABS( DL( 1 ) ),
     $              ABS( D( N ) )+ABS( DU( N-1 ) ) )
            DO 20 I = 2, N - 1
               ANORM = MAX( ANORM, ABS( D( I ) )+ABS( DL( I ) )+
     $                 ABS( DU( I-1 ) ) )
   20       CONTINUE
         END IF
      ELSE IF( <a name="LSAME.108"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( NORM, <span class="string">'I'</span> ) ) THEN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">        Find normI(A).
</span><span class="comment">*</span><span class="comment">
</span>         IF( N.EQ.1 ) THEN
            ANORM = ABS( D( 1 ) )
         ELSE
            ANORM = MAX( ABS( D( 1 ) )+ABS( DU( 1 ) ),
     $              ABS( D( N ) )+ABS( DL( N-1 ) ) )
            DO 30 I = 2, N - 1
               ANORM = MAX( ANORM, ABS( D( I ) )+ABS( DU( I ) )+
     $                 ABS( DL( I-1 ) ) )
   30       CONTINUE
         END IF
      ELSE IF( ( <a name="LSAME.122"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( NORM, <span class="string">'F'</span> ) ) .OR. ( <a name="LSAME.122"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( NORM, <span class="string">'E'</span> ) ) ) THEN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">        Find normF(A).
</span><span class="comment">*</span><span class="comment">
</span>         SCALE = ZERO
         SUM = ONE
         CALL <a name="ZLASSQ.128"></a><a href="zlassq.f.html#ZLASSQ.1">ZLASSQ</a>( N, D, 1, SCALE, SUM )
         IF( N.GT.1 ) THEN
            CALL <a name="ZLASSQ.130"></a><a href="zlassq.f.html#ZLASSQ.1">ZLASSQ</a>( N-1, DL, 1, SCALE, SUM )
            CALL <a name="ZLASSQ.131"></a><a href="zlassq.f.html#ZLASSQ.1">ZLASSQ</a>( N-1, DU, 1, SCALE, SUM )
         END IF
         ANORM = SCALE*SQRT( SUM )
      END IF
<span class="comment">*</span><span class="comment">
</span>      <a name="ZLANGT.136"></a><a href="zlangt.f.html#ZLANGT.1">ZLANGT</a> = ANORM
      RETURN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     End of <a name="ZLANGT.139"></a><a href="zlangt.f.html#ZLANGT.1">ZLANGT</a>
</span><span class="comment">*</span><span class="comment">
</span>      END

</pre>

 </body>
</html>

zlangt.f.html - 源码说明

本页面展示了「famous linear algebra library (LAPACK) ports to windows」中的 zlangt.f.html 源码文件，采用 HTML 编程语言编写，共 166 行代码。您可以在线阅读完整代码内容，也可以返回资源详情页下载完整源码包进行本地学习和开发。

虫虫下载站收录了大量与algebra相关的技术资源，包括源代码、技术文档、电路图等，是电子工程师和嵌入式开发者的专业学习平台。

⌨️ 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?