Changing Pure Function in Module
- To: mathgroup at smc.vnet.net
- Subject: [mg29822] Changing Pure Function in Module
- From: Flip at safebunch.com
- Date: Thu, 12 Jul 2001 02:52:35 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi All,
thank you to all who continue to respond to all of my questions ... and there
are always plenty of them.
I have the following function embedded in the findD code below.
a[1] =5;
a[n_]:= a[n] = (-1)^(n+1) (Abs[a[n-1]]+2)
In[225]:=
findD[n_]:=
Module[{c=0},NestWhile[(c++;(-1)^c(Abs[#]+2))&,5,JacobiSymbol[#,n]!=-1&]]
I would like to change the pure function to use the following (cleaner) function
that requires no starting value (and starts for n = 1).
In[255]:=
a[n_]:= a[n]= (-1)^(n+1)*(2n + 3)
Also, it would be important to test n prior to calling findD. If n is a perfect
square, findD will "never" converge. Is there a simple way to test if n is
square and tell the user ... try again ... n is a perfect square.
Again thank you for all of the help ... Wilson
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- From: Daniel Lichtblau <danl@wolfram.com>
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