Re: iterative convolution, discret convolution N times
- To: mathgroup at smc.vnet.net
- Subject: [mg102458] Re: [mg102424] iterative convolution, discret convolution N times
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Sun, 9 Aug 2009 18:22:12 -0400 (EDT)
- Reply-to: hanlonr at cox.net
fd[x_] := Piecewise[{{x + 1, 0 < x < 4}}]
n = 4;
For[i = 1; convn = fd[x], i <= n, i++,
convn = DiscreteConvolve[convn /. m -> x,
fd[x], x, m, Assumptions -> m > 0];
Print[FullSimplify[convn]]]
NestList[DiscreteConvolve[# /. m -> x,
fd[x], x, m] &,
fd[x], n] // Rest // FullSimplify
Bob Hanlon
---- Anna <petitmouton at gmail.com> wrote:
=============
HI, I'm trying to do N time convulution of a density funtion called
"fd" with itself . I tried to write an algorithm as shown
For[i = 1; convn = fd, i <= N, i++,
convn = DiscreteConvolve[convn, fd , x, m, Assumptions -> m > 0];
Print[convn]]
The initial function fd(x) has x as input variable. After the
convolution, the results convn(m) is in the function of m instead of
x. That's the reason why the algorithm I wrote doesn't work after the
first iteration since the DiscreteConvolve function couldn't find the
input in a function as x anymore.
I would like to ask a question is there a way to change the variable
of a function? for exemple: how can I replace a function y = x+1 by y=m
+1 ???? and is there another way to easily do a convolution N times of
the same function? Thank you very much.
Best regards,
Victoria