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Re: Problems with recursive function

• To: mathgroup at smc.vnet.net
• Subject: [mg87364] Re: Problems with recursive function
• From: dh <dh at metrohm.ch>
• Date: Tue, 8 Apr 2008 07:17:11 -0400 (EDT)
• References: <ftfela$bv1$1@smc.vnet.net>

Hi Frank,

if I understand correctly, you need to define a recursion with a stop 

criterion. You can do this by e.g.:

test[0,_]:=5;

test[n_,b_]:=test[n-1,b] b;

test[10,5]

if you have many calculations, it may be advantageously to store 

intermediate results:

test[n_,b_]:=test[n-1,b]=test[n-1,b] b;

hope this helps, Daniel



Frank Hechtner wrote:

> Dear Newsgroup,

> 

> I'm in trouble with a recursive function. the functios looks similar to 

> test[a_, b_] := test[a - 1, b]*b. A is the index b should just be an 

> argument of test.

> for any calculation i need to tell mathematica the first value of the 

> function, e.g. test[0, 5]=5. The problem is the following: the first 

> object is independent of b. does anyone know a way to tell mathematica 

> the following thing:

> 

>   test[0,b]=5 => test[0]=5 regardless to b.

> 

> Thanks for your help.

> 

> Frank

>