On the way back from the dentist, I figured that there is a rather
obvious solution to this sort of thing.
You can create a "queue" variable that stores "new instances to be done later".
In case it is not clear what I mean, using the AMOEBA example we would have:
<xsl:template name="AMOEBA">
<xsl:param name="queue" as="item()*"/>
<xsl:param name="location" as="xs:double+"/>
<xsl:param name="terrain" as="map(*)"/>
And then whenever you hit a situation where you need to split the
process, you add the new parameters to the $queue variable so that
they get processed whenever the current thread completes:
In the AMOEBA case, that might mean making the following call:
<xsl:call-template name="AMOEBA">
<xsl:with-param name="queue" select="(alternate_location,
alternate_terrain, $queue)"/>
<xsl:with-param name="location" select="new.location"/>
<xsl:with-param name="terrain" select="new.terrain"/>
</xsl:call-template>
where "alternate_location" and "alternate_terrain" are the inputs that
would be split off in the original example.
Then, when the current recursive process ends, you make a call with
starting info coming from the queue:
<xsl:call-template name="AMOEBA">
<xsl:with-param name="queue" select="tail(tail($queue))"/>
<xsl:with-param name="location" select="head($queue)"/>
<xsl:with-param name="terrain" select="head(tail($queue))"/>
</xsl:call-template>
-David
On Wed, Mar 12, 2014 at 12:43 PM, David Rudel <fwqhgads(_at_)gmail(_dot_)com>
wrote:
I'm looking for any pointers on speeding up an algorithm that uses
self-recursion, but the self-recursion can spawn multiple new
instances.
For example, imagine that the template AMOEBA is meant to model an
amoeba walking around on a surface.
AMOEBA is called with two parameters: a location indicating where the
amoeba is and a map indicating the terrain:
<xsl:template name="AMOEBA">
<xsl:param name="location" as "xs:double+"/>
<xsl:param name="Terrain" as "map(*)"/>
And based on the location and terrain, the amoeba takes a new step,
calling itself with the new location and a new terrain map. NOTE: the
new terrain map is a slight modification of the old terrain map.
But sometimes the Amoeba needs to split into two amoeba, so in some
cases the AMOEBA template will actually need to call two separate
versions of itself (with different locations and terrains).
Any tips for how to accomplish this with as good performance as
possible, given that it is impossible for both calls to be in tail
position?
-David
--
"A false conclusion, once arrived at and widely accepted is not
dislodged easily, and the less it is understood, the more tenaciously
it is held." - Cantor's Law of Preservation of Ignorance.
--
"A false conclusion, once arrived at and widely accepted is not
dislodged easily, and the less it is understood, the more tenaciously
it is held." - Cantor's Law of Preservation of Ignorance.
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