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Re: [xsl] Performance improvement for a recursive function?
Subject: Re: [xsl] Performance improvement for a recursive function? From: Wolfgang Laun <wolfgang.laun@xxxxxxxxx> Date: Tue, 13 Dec 2011 08:46:28 +0100 |
This function permits processing of all contained commands. I don't have the time to analyze what should be done for each; I saw that m0,0 was dropped. It's fast enough now :-) -W <xsl:function name="my:compose-path-data" as="xs:string*"> <xsl:param name="data" as="xs:string*"/> <xsl:analyze-string select = "$data" regex = "[ Mlm](\d+),(\d+)|[hv](\d+)|z"> <xsl:matching-substring> <xsl:variable name="cmd" select="substring(regex-group(0),1,1)"/> <xsl:choose> <xsl:when test="$cmd = (' ', 'M', 'l', 'm')"> <xsl:value-of select="concat($cmd,regex-group(1),',',regex-group(2))"/> </xsl:when> <xsl:when test="$cmd = ('h', 'v')"> <xsl:value-of select="concat($cmd,regex-group(3))"/> </xsl:when> <xsl:when test="$cmd = 'z'"> <xsl:value-of select="$cmd"/> </xsl:when> </xsl:choose> </xsl:matching-substring> </xsl:analyze-string> </xsl:function> On 13 December 2011 01:07, Manfred Staudinger <manfred.staudinger@xxxxxxxxx> wrote: > Hi, > > I need some help to improve the performance of a function, as I have > run out of ideas what to change! > > In the process to convert some data to SVG I transform (or even break > up) @Data attribute of the Path element and then use the function > my:compose-path-data [1] to put the parts together into a string > again. The attribute string is a succession of path commands, where > each path command (see the global variable below) consists of a one > byte character followed by zero, one, or two integers. Having about > 2200 Path elements, most of them have a @Data attribute with between 5 > an 50 path commands. > > A few attribute strings are bigger (up to 1MB) and contain up to > 100000 path commands. As the function is called for each path command > it is tail recursive, but the performance is still a big problem: to > process 41337 path commands it takes 861 sec! The first 5000 path > commands are processed in 14 sec (at 355.87 per sec) the last 5000 > take 671 sec (only at 7.5 per sec). > > What Saxon reports [2] is consistent with the above. In case you want > to try it, I have uploaded the specific test case here: > http:///test.rudolphina.org/test01-perform-data.xsl > http:///test.rudolphina.org/test01-perform-data-org.xml > > Using Saxon-HE 9.3.0.5J and Java version 1.6.0_14 on Windows. XP Home. > Hardware ASUS Eee PC 1000H with Intel. Atom N270 (1.60 GHz) > > Regards, > Manfred > > [1] > <xsl:function name="my:compose-path-data" as="xs:string*"> > <xsl:param name="c" as="xs:integer*"/> > <xsl:param name="i-c" as="xs:integer"/> > <xsl:param name="xy" as="xs:integer*"/> > <xsl:param name="i-xy" as="xs:integer"/> > <xsl:param name="i-end" as="xs:integer"/> > <xsl:param name="result" as="xs:string?"/> > <xsl:variable name="cmd" select="key('path', $c[$i-c], $path-cmd)" > as="element()?"/> > <xsl:sequence select="if ($i-c gt $i-end) > then $result > else my:compose-path-data($c, $i-c + 1, > $xy, $i-xy + xs:integer($cmd/n), > $i-end, > concat($result, $cmd/@char, if ($cmd/n=2) > then (: M, m, l, (blank) :) concat($xy[$i-xy], ',', $xy[$i-xy+1]) > else if ($cmd/n=1) > then (: h, v :) string($xy[$i-xy]) > else (: z :) ()) > )"/> > </xsl:function> > > and on the stylesheet level > <xsl:variable name="path-cmd"> > <path> > <cmd char=" "><n>2</n><code>32</code></cmd> > <cmd char="M"><n>2</n><code>77</code></cmd> > <cmd char="l"><n>2</n><code>108</code></cmd> > <cmd char="m"><n>2</n><code>109</code></cmd> > <cmd char="h"><n>1</n><code>104</code></cmd> > <cmd char="v"><n>1</n><code>118</code></cmd> > <cmd char="z"><n>0</n><code>122</code></cmd> > </path> > </xsl:variable> > <xsl:key name="path" match="cmd" use="xs:integer(code)"/><!-- $path-cmd --> > > [2] > Stylesheet compilation time: 4218 milliseconds > Using parser org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser > net.sf.saxon.tree.tiny.TinyBuilder > Tree built in 1375 milliseconds > Tree size: 4 nodes, 0 characters, 11 attributes > Execution time: 14m 31.579s (871579ms) > Memory used: 36559128 > NamePool contents: 33 entries in 33 chains. 8 prefixes, 8 URIs
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