RE: product formula in mathematica
- To: mathgroup at smc.vnet.net
- Subject: [mg68757] RE: [mg68702] product formula in mathematica
- From: "David Annetts" <davidannetts at aapt.net.au>
- Date: Fri, 18 Aug 2006 03:12:01 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
> 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.
Depends exactly what you want ....
There is a form of the product function that takes a step, eg.
Product[i, {i, 1, 10, 2}]
However, if you want something particularly unusual, then you can simulate
Product by applying Times[] to a list, eg.
Times @@ Range[1, 10, 2]
Or
Times @@ (# &) /@ {2, 3, 5, 7, 11, 13, 17, 19}
Which should be the same as
Product[Prime[x], {x, 8}]
Regards,
Dave.