Re: RandomChoice does not accept null weights
- To: mathgroup at smc.vnet.net
- Subject: [mg83456] Re: RandomChoice does not accept null weights
- From: Helen Read <hpr at together.net>
- Date: Wed, 21 Nov 2007 02:43:58 -0500 (EST)
- References: <fhrs7v$5pe$1@smc.vnet.net> <fhu6o3$6q7$1@smc.vnet.net>
- Reply-to: HPR <read at math.uvm.edu>
Jean-Marc Gulliet wrote: > Szabolcs Horv=C3=A1t wrote: > >>RandomChoice does not accept 0 weights. >> >>Is this the intended behaviour? > > As far as I am aware of, the help page for RandomChoice does not state > or imply that the weights must be positive. OTOH, the above error > message clearly claims that the weight must be positive values. Shall we > > conclude that the documentation is again flawed or incomplete or > misleading or ... (who knows what!) and that the behavior of > RandomChoice is at it is by design? It is strange that the documentation pages for RandomChoice and RandomSample don't seem to mention that the weights must be positive. I did however find this information here (in the section on Random Elements): tutorial/RandomNumberGeneration <<If the first argument to RandomChoice or RandomSample is a list, elements are selected with equal probability. The weight specification defines a distribution on the set of Subscript[e, i]s. The weights must be positive, but need not sum to 1.>> It's a little baffling that they neglected to mention this on the pages for RandomChoice and RandomSample. -- Helen Read University of Vermont