RE: Calculating cumulative values

Thanks, Dimitre.

Two questions -

a) Will this work with .Net 2.0?
 
b) What are the external files : func-scanlDVC.xsl and func-Operators.xsl?

Simon

-----Original Message-----
From: Dimitre Novatchev [mailto:dnovatchev@xxxxxxxxx] 
Sent: February 3, 2007 2:50 PM
To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
Subject: Re:  Calculating cumulative values

On 2/3/07, Andrew Welch <andrew.j.welch@xxxxxxxxx> wrote:

>
> You can just use XPath here, no need for recursion:
>
> <xsl:template match="point">
>  <xsl:copy>
>   <xsl:copy-of select="@*"/>
>   <xsl:attribute name="y2">
>     <xsl:value-of select="sum(./@y1|preceding-sibling::point[@x = 
> current()/@x]/@y1)"/>
>   </xsl:attribute>
>  </xsl:copy>
> </xsl:template>


However evaluating this XPath expression repeatedly is O(N^2) and will
probably be slow for long lists.

Here is a solution, using the FXSL function

      f:scanl1()

This transformation:

<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 xmlns:f="http://fxsl.sf.net/"
 exclude-result-prefixes="f"
>
  <xsl:import href="../f/func-scanlDVC.xsl"/>
  <xsl:import href="../f/func-Operators.xsl"/>

  <!-- To be applied on testFunc-scanlDVC3.xml -->
  <xsl:output omit-xml-declaration="yes" indent="yes"/>


  <xsl:template match="node()|@*">
    <xsl:copy>
      <xsl:apply-templates select="node()|@*"/>
    </xsl:copy>
  </xsl:template>

  <xsl:template match="set">
    <xsl:copy>
      <xsl:copy-of select="@*"/>
      <xsl:for-each-group select="point" group-by="@x">
         <xsl:for-each select="f:scanl1(f:add(), current-group()/@y1)">
            <point x="{current-group()[1]/@x}" y="{.}"/>
         </xsl:for-each>
     </xsl:for-each-group>
    </xsl:copy>
 </xsl:template>
</xsl:stylesheet>

When applied against the originally provided xml document:

<root id="theroot">
	<set id="1">
		<point x="1" y1="2" />
		<point x="1" y1="3" />
		<point x="1" y1="0" />
		<point x="1" y1="2" />
		<point x="1" y1="2" />
		<point x="2" y1="3" />
		<point x="2" y1="0" />
		<point x="2" y1="2" />
		<point x="3" y1="2" />
		<point x="3" y1="3" />
		<point x="3" y1="1" />
		<point x="3" y1="2" />
		<point x="3" y1="2" />
	</set>
	<set id="2">
		<point x="1" y1="2" />
		<point x="1" y1="3" />
		<point x="1" y1="0" />
		<point x="1" y1="2" />
		<point x="2" y1="2" />
		<point x="3" y1="2" />
		<point x="3" y1="2" />
		<point x="3" y1="2" />
	</set>
	<set id="n">
		<point x="1" y1="2" />
		<point x="1" y1="3" />
		<point x="1" y1="2" />
		<point x="2" y1="3" />
		<point x="2" y1="0" />
		<point x="2" y1="2" />
		<point x="3" y1="3" />
	</set>
</root>

produces the wanted result:

<root id="theroot">
   <set id="1">
      <point x="1" y="2"/>
      <point x="1" y="5"/>
      <point x="1" y="5"/>
      <point x="1" y="7"/>
      <point x="1" y="9"/>
      <point x="2" y="3"/>
      <point x="2" y="3"/>
      <point x="2" y="5"/>
      <point x="3" y="2"/>
      <point x="3" y="5"/>
      <point x="3" y="6"/>
      <point x="3" y="8"/>
      <point x="3" y="10"/>
   </set>
   <set id="2">
      <point x="1" y="2"/>
      <point x="1" y="5"/>
      <point x="1" y="5"/>
      <point x="1" y="7"/>
      <point x="2" y="2"/>
      <point x="3" y="2"/>
      <point x="3" y="4"/>
      <point x="3" y="6"/>
   </set>
   <set id="n">
      <point x="1" y="2"/>
      <point x="1" y="5"/>
      <point x="1" y="7"/>
      <point x="2" y="3"/>
      <point x="2" y="3"/>
      <point x="2" y="5"/>
      <point x="3" y="3"/>
   </set>
</root>


--
Cheers,
Dimitre Novatchev
---------------------------------------
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