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Re: convol [message #92059 is a reply to message #92056]

Sun, 04 October 2015 03:44

Yngvar Larsen
Messages: 134
Registered: January 2010

Senior Member

On Sunday, 4 October 2015 11:15:15 UTC+2, Dete van Eeden wrote:
> On Sunday, October 4, 2015 at 11:05:19 AM UTC+2, Fabien wrote:
>> On 10/04/2015 10:49 AM, Dete van Eeden wrote:
>>>> > Hallo
>>>> > > >
>>>> > > >I want to use the convol function for an array and a kernel.
>>>> > > >
>>>> > > >I am not sure how the center option works? how and where do I define it?
>>>> > > >
>>>> > > >at the moment the result is not quite what it should be...
>>>> > > >
>>>> > > >Any advise?
>>>> >
>>>> >https://xkcd.com/722/
>>>> >
>>>> >Cheers,
>>>> >
>>>> >Fabien
>>> comics??
>>
>> This comic is a perfect illustration of the way you described your
>> problem. People here are very helpful but they have no crystal ball and
>> can't give you a better advice than "press more buttons".
>>
>> http://www.catb.org/esr/faqs/smart-questions.html#beprecise
>
> thanks for being an idiot

(THIS is definitively not the way to get an answer anywhere on the net that I know of. But anyway, here it goes.)

The issue here is that you don't describe why CONVOL doesn't work like you expect. Given that CONVOL is extremely well documented, including the CENTER keyword, it is hard to know what your problem is.

http://www.exelisvis.com/docs/CONVOL.html#C_854643309_676409

You should describe what you did and why that isn't what you expected if you want answers.

A couple of (documented) gotchas are that

1) the CENTER keyword is set by default, and

2) CONVOL does not reverse the kernel unless /REVERSE is set, and thus by default calculates correlation rather than convolution in the mathematical sense.

--
Yngvar

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[Message index]

		convol By: Dete van Eeden on Sun, 04 October 2015 01:18
		Re: convol By: Fabzi on Sun, 04 October 2015 01:37
		Re: convol By: Dete van Eeden on Sun, 04 October 2015 01:49
		Re: convol By: Fabzi on Sun, 04 October 2015 02:05
		Re: convol By: Dete van Eeden on Sun, 04 October 2015 02:15
		Re: convol By: Fabzi on Sun, 04 October 2015 02:23
		Re: convol By: Yngvar Larsen on Sun, 04 October 2015 03:44
		Re: convol By: Paul Van Delst[1] on Mon, 05 October 2015 04:37

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