Re: ListConvolve Problem?

• To: mathgroup at smc.vnet.net
• Subject: [mg33367] Re: ListConvolve Problem?
• From: "Allan Hayes" <hay at haystack.demon.co.uk>
• Date: Mon, 18 Mar 2002 00:18:43 -0500 (EST)
• References: <a71sif\$ghd\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```poonam" <poonam_pandey at hotmail.com> wrote in message
news:a71sif\$ghd\$1 at smc.vnet.net...
> The following is the outout for the listconvolve:
>
> In[1]:= ListConvolve[{1,1,1},{0.5,1,0.5}]
>
> Out[1]= {2.}
>
>
> whereas if i manually do a convolution with my pencil and paper,
>
> Out  = {0.5 , 1.5 , 2. , 1.5 , 0.5}

poonam,
We have to pad with zeros and control start and finish:

ListConvolve[{1,1,1},{0.5,1,0.5},{1,-1},{0}]

{0.5,1.5,2.,1.5,0.5}

The following, together with the Help Browser, may help

ListConvolve[{a,b,c},{p,q,r},{1,-1},{0}]

{a p,b p+a q,c p+b q+a r,c q+b r,c r}
--
Allan

---------------------
Allan Hayes
Mathematica Training and Consulting
Leicester UK
www.haystack.demon.co.uk
hay at haystack.demon.co.uk
Voice: +44 (0)116 271 4198
Fax: +44 (0)870 164 0565

```

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