Re: product formula in mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg68797] Re: product formula in mathematica*From*: Peter Pein <petsie at dordos.net>*Date*: Fri, 18 Aug 2006 03:13:00 -0400 (EDT)*References*: <ec19d4$oie$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

frou schrieb: > Hi I am interested in doing a product over a set of indices that are > not continuous > Product [ f(x_i) , { x_i, 1,3,4,9}] Is this possible it appears > that the iterator wouldonly take sequences such as 1...10 etc. > > Thanks > The first method works for arbitrary lists: In[1]:= Times@@(f/@{1,3,4,9}) Out[1]= f[1] f[3] f[4] f[9] and the second is very specialized ;-) In[2]:= Product[f[FromDigits[IntegerDigits[k,2],3]],{k,4}] Out[2]= f[1] f[3] f[4] f[9] (just kidding - sorry) Peter