dlabad.f.html

来自「famous linear algebra library (LAPACK) p」· HTML 代码 · 共 78 行

HTML
78 行
字号 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
  <title>dlabad.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.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="DLABAD.1"></a><a href="dlabad.f.html#DLABAD.1">DLABAD</a>( SMALL, LARGE )
<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>      DOUBLE PRECISION   LARGE, SMALL
<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="DLABAD.14"></a><a href="dlabad.f.html#DLABAD.1">DLABAD</a> takes as input the values computed by <a name="DLAMCH.14"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a> for underflow and
</span><span class="comment">*</span><span class="comment">  overflow, and returns the square root of each of these values if the
</span><span class="comment">*</span><span class="comment">  log of LARGE is sufficiently large.  This subroutine is intended to
</span><span class="comment">*</span><span class="comment">  identify machines with a large exponent range, such as the Crays, and
</span><span class="comment">*</span><span class="comment">  redefine the underflow and overflow limits to be the square roots of
</span><span class="comment">*</span><span class="comment">  the values computed by <a name="DLAMCH.19"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a>.  This subroutine is needed because
</span><span class="comment">*</span><span class="comment">  <a name="DLAMCH.20"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a> does not compensate for poor arithmetic in the upper half of
</span><span class="comment">*</span><span class="comment">  the exponent range, as is found on a Cray.
</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">  SMALL   (input/output) DOUBLE PRECISION
</span><span class="comment">*</span><span class="comment">          On entry, the underflow threshold as computed by <a name="DLAMCH.27"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a>.
</span><span class="comment">*</span><span class="comment">          On exit, if LOG10(LARGE) is sufficiently large, the square
</span><span class="comment">*</span><span class="comment">          root of SMALL, otherwise unchanged.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  LARGE   (input/output) DOUBLE PRECISION
</span><span class="comment">*</span><span class="comment">          On entry, the overflow threshold as computed by <a name="DLAMCH.32"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a>.
</span><span class="comment">*</span><span class="comment">          On exit, if LOG10(LARGE) is sufficiently large, the square
</span><span class="comment">*</span><span class="comment">          root of LARGE, otherwise unchanged.
</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">     .. Intrinsic Functions ..
</span>      INTRINSIC          LOG10, 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><span class="comment">*</span><span class="comment">     If it looks like we're on a Cray, take the square root of
</span><span class="comment">*</span><span class="comment">     SMALL and LARGE to avoid overflow and underflow problems.
</span><span class="comment">*</span><span class="comment">
</span>      IF( LOG10( LARGE ).GT.2000.D0 ) THEN
         SMALL = SQRT( SMALL )
         LARGE = SQRT( LARGE )
      END IF
<span class="comment">*</span><span class="comment">
</span>      RETURN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     End of <a name="DLABAD.53"></a><a href="dlabad.f.html#DLABAD.1">DLABAD</a>
</span><span class="comment">*</span><span class="comment">
</span>      END

</pre>

 </body>
</html>

dlabad.f.html - 源码说明

本页面展示了「famous linear algebra library (LAPACK) ports to windows」中的 dlabad.f.html 源码文件，采用 HTML 编程语言编写，共 78 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?