--- /dev/null
+#!/usr/bin/env python
+
+def triangle(n):
+ """generate a YACS graph for computation of the Pascal triangle
+
+ parameter: rank of the triangle.
+ Use module decimal for an exact calculation with big numbers.
+ The last node gives the sum of rank n (=2**n) and also a direct calculation of 2**n.
+ """
+
+ print """
+<proc>
+ <!-- types -->
+ <!-- inline -->
+
+<inline name="node_0_0" >
+<script><code>
+import time
+from decimal import *"""
+ print "getcontext().prec = " + str(1+n/3)
+ print """
+aa=Decimal(a)
+bb=Decimal(b)
+cc=aa+bb
+c=str(cc)
+print "cc=",cc
+time.sleep(1)
+</code></script>
+<inport name="a" type="string"/>
+<inport name="b" type="string"/>
+<outport name="c" type="string"/>
+</inline>"""
+
+ print """
+<inline name="collect" >
+<script><code>"""
+ print "import time"
+ print "from decimal import *"
+ print "getcontext().prec = " + str(1+n/3)
+ print "tot = Decimal(0)"
+ print "for i in range (" + str(n+1) + "):"
+ print " v='a' + str(i)"
+ print " tot+=Decimal(eval(v))"
+ print "print tot"
+ print "result=str(tot)"
+ print "ref=Decimal(2)**" + str(n)
+ print "reference=str(ref)"
+ print "time.sleep(1)"
+ print "</code></script>"
+ for i in range (n+1):
+ inport='<inport name="a' + str(i) + '" type="string"/>'
+ print inport
+ pass
+ print '<outport name="result" type="string"/>'
+ print '<outport name="reference" type="string"/>'
+ print "</inline>"
+ print
+
+ for i in range (1,n+1):
+ for j in range (i+1):
+ node="node_" + str(i) +"_" + str(j)
+ nodetxt='<node name="'+node+'" type="node_0_0"></node>'
+ print nodetxt
+ pass
+ pass
+
+ print """
+
+ <!-- service -->
+ <!-- control -->
+
+ """
+
+ for i in range (n):
+ for j in range (i+1):
+ fromnode="node_" + str(i) +"_" + str(j)
+ tonode1="node_" + str(i+1) +"_" + str(j)
+ tonode2="node_" + str(i+1) +"_" + str(j+1)
+ control1='<control> <fromnode>'+fromnode+'</fromnode> <tonode>'+tonode1+'</tonode> </control>'
+ control2='<control> <fromnode>'+fromnode+'</fromnode> <tonode>'+tonode2+'</tonode> </control>'
+ print control1
+ print control2
+ pass
+ pass
+ for i in range (n+1):
+ fromnode="node_" + str(n) +"_" + str(i)
+ control='<control> <fromnode>'+fromnode+'</fromnode> <tonode>collect</tonode> </control>'
+ print control
+ pass
+
+ print """
+
+ <!-- datalinks -->
+
+ """
+
+ for i in range (n):
+ for j in range (i+1):
+ fromnode="node_" + str(i) +"_" + str(j)
+ tonode1="node_" + str(i+1) +"_" + str(j)
+ tonode2="node_" + str(i+1) +"_" + str(j+1)
+ datafrom='<fromnode>' + fromnode + '</fromnode> <fromport>c</fromport>'
+ datato1 ='<tonode>' + tonode1 + '</tonode> <toport>b</toport>'
+ datato2 ='<tonode>' + tonode2 + '</tonode> <toport>a</toport>'
+ print '<datalink>'
+ print ' ' + datafrom
+ print ' ' + datato1
+ print '</datalink>'
+ print '<datalink>'
+ print ' ' + datafrom
+ print ' ' + datato2
+ print '</datalink>'
+ pass
+ pass
+ for i in range (n+1):
+ fromnode="node_" + str(n) +"_" + str(i)
+ datafrom='<fromnode>' + fromnode + '</fromnode> <fromport>c</fromport>'
+ toport='a' + str(i)
+ datato ='<tonode>collect</tonode> <toport>' + toport + '</toport>'
+ print '<datalink>'
+ print ' ' + datafrom
+ print ' ' + datato
+ print '</datalink>'
+
+
+ print """
+
+ <!--parameters -->
+
+ """
+
+ print """
+ <parameter>
+ <tonode>node_0_0</tonode> <toport>a</toport>
+ <value><string>0</string></value>
+ </parameter>
+ <parameter>
+ <tonode>node_0_0</tonode> <toport>b</toport>
+ <value><string>1</string></value>
+ </parameter>
+ """
+
+ for i in range (1,n+1):
+ node1="node_" + str(i) +"_" + str(0)
+ node2="node_" + str(i) +"_" + str(i)
+ tonode1 =' <tonode>' + node1 + '</tonode> <toport>a</toport>'
+ tonode2 =' <tonode>' + node2 + '</tonode> <toport>b</toport>'
+ print '<parameter>'
+ print tonode1
+ print ' <value><string>0</string></value>'
+ print '</parameter>'
+
+ print '<parameter>'
+ print tonode2
+ print ' <value><string>0</string></value>'
+ print '</parameter>'
+
+ print """
+
+</proc>
+ """
+
+if __name__ == "__main__":
+ import sys
+ usage ="""Usage: %s rank > file.xml
+ where rank is positive integer > 2
+ """
+ try:
+ rank = int(sys.argv[1])
+ if rank <2:
+ raise ValueError("rank must be >1")
+ except (IndexError, ValueError):
+ print usage%(sys.argv[0])
+ sys.exit(1)
+ pass
+ triangle(rank)
+ pass
