Re: [xsl] Performance improvement for a recursive function?

[Wolfgang Laun <wolfgang.laun@xxxxxxxxx>]

I forgot to mention that the result of this function must be processed with
   string-join(my:compose-path-data($Data),'')
-W

On 13 December 2011 08:46, Wolfgang Laun <wolfgang.laun@xxxxxxxxx> wrote:
> 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