Hi Leo,
I ran this with BaseX 7.8.2:
declare namespace my = "my:my";
declare function my:increasing($seq as xs:double*) as xs:boolean
{empty($seq[2])
or
$seq[1] lt $seq[2] and my:increasing(subsequence($seq, 2))
};
let $v:=(1 to 10000)
return my:increasing($v)
And here is the result (do note this below: - marking as ***tail
call***: my:increasing(fn:subsequence($seq_0, 2)) )
Total Time: 3.74ms (for 100 000 - long sequence the time was 17.77ms,
for 1 000 000 - long sequence the time was 207.56ms)
Compiling:
- removing redundant xs:boolean cast.
- marking as tail call: my:increasing(fn:subsequence($seq_0, 2))
- pre-evaluating (1 to 10000)
- inlining let $v_1 := (1 to 10000)
- simplifying flwor expression
Query:
declare namespace my = "my:my"; declare function my:increasing($seq as
xs:double*)as xs:boolean {empty($seq[2]) or $seq[1] lt $seq[2] and
my:increasing(subsequence($seq, 2)) }; let $v:=(1 to 10000) return
my:increasing($v)
Optimized Query:
declare function my:increasing($seq_0 as xs:double*) as xs:boolean {
(fn:empty($seq_0[2]) or (($seq_0[1] lt $seq_0[2]) and
my:increasing(fn:subsequence($seq_0, 2)))) };
my:increasing((1 to 10000))
Result:
- Hit(s): 1 Item
- Updated: 0 Items
- Printed: 4 Bytes
- Read Locking: none
- Write Locking: none
Timing:
- Parsing: 0.91 ms
- Compiling: 0.19 ms
- Evaluating: 2.5 ms
- Printing: 0.14 ms
- Total Time: 3.74 ms
Query plan:
<QueryPlan>
<StaticFunc name="my:increasing" arg0="seq">
<Or tailCall="true">
<FNSimple name="empty(item)">
<IterPosFilter>
<VarRef>
<Var name="$seq" id="0" as="xs:double*"/>
</VarRef>
<Pos min="2" max="2"/>
</IterPosFilter>
</FNSimple>
<And tailCall="true">
<CmpV op="lt">
<IterPosFilter>
<VarRef>
<Var name="$seq" id="0" as="xs:double*"/>
</VarRef>
<Pos min="1" max="1"/>
</IterPosFilter>
<IterPosFilter>
<VarRef>
<Var name="$seq" id="0" as="xs:double*"/>
</VarRef>
<Pos min="2" max="2"/>
</IterPosFilter>
</CmpV>
<StaticFuncCall name="Q{my:my}increasing" tailCall="true">
<FNSeq name="subsequence(items,start[,len])">
<VarRef>
<Var name="$seq" id="0" as="xs:double*"/>
</VarRef>
<Int value="2" type="xs:integer"/>
</FNSeq>
</StaticFuncCall>
</And>
</Or>
</StaticFunc>
<StaticFuncCall name="Q{my:my}increasing" tailCall="false">
<RangeSeq from="1" to="10000"/>
</StaticFuncCall>
</QueryPlan>
On Thu, Mar 26, 2015 at 12:48 PM, Dimitre Novatchev
<dnovatchev(_at_)gmail(_dot_)com> wrote:
Leo,
I tried it with an xQuery function (I know it does not belong here ;-)) and
had a stack problem with a sequence with 10000 elements ;-( (Oxygen 16.1)
I think I know what the issue is most likely.
I can investigate further only after I am back at home from work, but
my guess is that if you use BaseX, there will be no SO problem.
Cheers,
Dimitre
On Thu, Mar 26, 2015 at 12:40 PM, Leo Studer
leo(_dot_)studer(_at_)varioweb(_dot_)ch
<xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com> wrote:
Dimitre
the question came up in a XML Schema 1.1 assertion where only xPath 2.0
expressions are allowed.
Dimitre, yes, this is nice, however can not be used in xsd:assertions.
Do you mean that you cannot use an XSLT function?
And there is a stack problem with large sequences.
I tried it with an xQuery function (I know it does not belong here ;-)) and
had a stack problem with a sequence with 10000 elements ;-( (Oxygen 16.1)
There shouldn't be such problem with this particular function, if the
XSLT processor recognizes and optimizes tail recursion.
Always
Leo
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Cheers,
Dimitre Novatchev
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