Hi Hermann, thanks for your interesting comparison. I'd like to point out that the loop around the calculation (for $h in 1 to $N) might be optimized away by a query compiler. If this happens, the only thing that would be measured in the query would be the concatenation of 10 million results.
But I completely agree that it's difficult to formulate an example that is easy to compare if as long as we have no dynamic input. Christian ______________________________________________ On Mon, Feb 3, 2014 at 11:56 AM, Hermann Stamm-Wilbrandt <[email protected]> wrote: > Thanks for your XQuery 1-dimensional sample. > > There are 4 XQuery with JSONiq implemenations named on jsoniq.org: > 28.io, Zorba, IBM Websphere DataPower Integration Appliance and Pascal > XQuery engine > > It seems not to be that easy to measure runtime. > Since http://try.zorba.io allows to share and run code I used that. > The method I found was to place Zorba's datetime:current-time() in result > sequence as first and last elements. > And the matrix multiplications need to be executed often to result in > measurable times (I did use 10.000.000). > > These are JSONiq (1) and your XQuery (2) implemenations: > http://try.zorba.io/queries/xquery/vq+kL9tWK+jmntDZz0oxDcyrypA= > http://try.zorba.io/queries/xquery/NIlfOIBmkdvt8+2zNmvM8Hf1+bo= > > The times reported are quite different although run on same processor: > PT1.713634S (JSONiq) versus PT9.77805S (XQuery) > > Yes, that is only result for one processor. But I would assume even (much) > bigger differences in case the matrix dimensions become bigger and not toy > like as in the examples. > > > (1) > import module namespace datetime = > "http://www.zorba-xquery.com/modules/datetime";; > > declare variable $A := [ > [1,2], > [3,4], > [5,6], > [7,8] > ]; > declare variable $B := [ > [1,2,3], > [4,5,6] > ]; > declare variable $N := 10000000; > > let $R := ( datetime:current-time(), > for $h in 1 to $N return > [ > for $i in 1 to count(jn:members($A)) return > [ > for $k in 1 to count(jn:members($B(1))) return > fn:sum( > for $j in 1 to count(jn:members($B)) return > $A($i)($j) * $B($j)($k) > ) > ] > ] > , datetime:current-time() ) > > return $R[count($R)] - $R[1] > > (2) > import module namespace datetime = > "http://www.zorba-xquery.com/modules/datetime";; > > declare variable $a:=(2, (:2 columns :) 1,2, 3,4, 5,6, 7,8); > declare variable $b:=(3, (:3 columns :) 1,2,3, 4,5,6); > declare variable $N := 10000000; > > let $R := ( datetime:current-time(), > for $h in 1 to $N return > ( $b[1], for $i in 1 to xs:int((count($a) -1) div $a[1]), $j in 1 to > xs:int($b[1]) return > sum( for $k in 1 to xs:int($a[1]) return ($a[($i -1)*$a[1]+$k+1] * $b > [($k -1)*$b[1]+$j+1]) ) ) > , datetime:current-time() ) > > return $R[count($R)] - $R[1] > > > Mit besten Gruessen / Best wishes, > > Hermann Stamm-Wilbrandt > Level 3 support for XML Compiler team and Fixpack team lead > WebSphere DataPower SOA Appliances > https://www.ibm.com/developerworks/mydeveloperworks/blogs/HermannSW/ > https://twitter.com/HermannSW/ > http://stamm-wilbrandt.de/GraphvizFiddle/ > ---------------------------------------------------------------------- > IBM Deutschland Research & Development GmbH > Vorsitzende des Aufsichtsrats: Martina Koederitz > Geschaeftsfuehrung: Dirk Wittkopp > Sitz der Gesellschaft: Boeblingen > Registergericht: Amtsgericht Stuttgart, HRB 243294 > > > > From: David Carlisle <[email protected]> > > To: Hermann Stamm-Wilbrandt/Germany/IBM@IBMDE, [email protected], > > Date: 02/02/2014 01:44 AM > > Subject: Re: [xquery-talk] Matrix Multiplication (JSONiq) > > > > > > > On 01/02/2014 23:33, Hermann Stamm-Wilbrandt wrote: >> >> Last Sylvester there was a thread on Matrix Multiplication in >> XQuery >> http://markmail.org/message/7q7qnbbnjo7cljzv?q=list:com.x-query.talk > +matrix+multiplication >> >> > >> >> The biggest problem identified was that XQuery does not allow for >> efficient representation of 2+dimensional arrays. >> > > well it does, but as in other languages that only really have 1-D arrays > (or languages such as C or Fortran where 2D arrays are a thin veneer > over 1D arrays), you need to store a 2 D array as a 1D array with an > additional integer giving the stride or leading dimension (in row or > column order). To keep the arrays self contained I stored this as the > first item in each sequence in the example below. > > > > >> JSON does provide 2+dimensional arrays for free. >> >> I did not measure performance yet, but this JSONiq script looks very >> similar to what would be done in C: >> http://try.zorba.io/queries/xquery/jFd3Q8f82HuZGzcYDzQpdN4SdfY= >> >> declare variable $A := [ [1,2], [3,4], [5,6], [7,8] ]; declare >> variable $B := [ [1,2,3], [4,5,6] ]; >> >> [ for $i in 1 to count(jn:members($A)) return [ for $k in 1 to >> count(jn:members($B(1))) return fn:sum( for $j in 1 to >> count(jn:members($B)) return $A($i)($j) * $B($j)($k) ) ] ] >> >> > > In Xquery 1 you could do > > > let $a:=(2, (:2 columns :) > 1,2, > 3,4, > 5,6, > 7,8), > > $b:=(3, (:3 columns :) > 1,2,3, > 4,5,6) > > return > > ( > $b[1], > for $i in 1 to xs:int((count($a) -1) div $a[1]), > $j in 1 to xs:int($b[1]) > return > sum( > for $k in 1 to xs:int($a[1]) return > ($a[($i -1)*$a[1]+$k+1] * $b[($k -1)*$b[1]+$j+1]) > ) > ) > > > which produces > > 3 (:3 columns :) > 9 12 15 > 19 26 33 > 29 40 51 > 39 54 69 > > > >> And much simpler than in XSLT: >> http://rosettacode.org/wiki/Matrix_multiplication#XSLT_1.0: >> >> > > As the above is in fact only Xpath 2, you could do the identical > expression in XSLT 2 > > > David > > > > > _______________________________________________ > [email protected] > http://x-query.com/mailman/listinfo/talk _______________________________________________ [email protected] http://x-query.com/mailman/listinfo/talk
