Re: Function for complex polynomial with variable number of arguments
- To: mathgroup at smc.vnet.net
- Subject: [mg123542] Re: Function for complex polynomial with variable number of arguments
- From: Christopher Young <cy56 at comcast.net>
- Date: Sat, 10 Dec 2011 07:31:27 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <201112081021.FAA18802@smc.vnet.net> <4EE0E621.3050600@math.umass.edu>
Thanks, this looks like the way to do it here, since I need to
distinguish a possible scaling constant from the roots, and
LocatorAutoCreate hands me a list of points.
On Dec 8, 2011, at 11:30 AM, Murray Eisenberg wrote:
> I presume you want the constant 1 as result in case you have an empty
list of points, as the product of an empty list should be 1 in order for
the generalized associative rule to hold for multiplication.
>
> There's an easy solution, obtained by making things simpler: avoid
indices entirely and directly use list-manipulation:
>
> poly[z_, p_] := Times @@ (z - p)
>
> poly[z, {a + b I, c + d I, c + d I}]
> (-a - I b + z) (-c - I d + z)^2
>
> poly[z, {a + b I}]
> -a - I b + z
>
> poly[z, {}]
> 1
>
> If you insist on your original syntax, then change the above to:
>
> poly2[z_, p___] := Times @@ (z - {p})
Chris Young
cy56 at comcast.net
- References:
- Function for complex polynomial with variable number of arguments
- From: Chris Young <cy56@comcast.net>
- Function for complex polynomial with variable number of arguments