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Re: how to create a LOG array from A to B [message #79001 is a reply to message #78999]

Thu, 12 January 2012 11:52

Michael Galloy
Messages: 1114
Registered: April 2006

Senior Member

On 1/12/12 12:27 PM, nata wrote:
> Hello guys,
>
> If I want to create an array of N positions from A to B I can do it
> like this :
> result=FINDGEN(N)*(B-A)/(N-1)+A
>
> Right now I would like to create the same array but with a logaritmic
> "distribution" and for any positive A and B.
> For example, for A = 0, B = 1 and N=10 the result should be
> ALOG10(1+FINDGEN(10))
>
> This is easy if A and B are powers of 10 but I don't know how to solve
> this problem with any other numbers.
> Thnak you in advance for your help,
>
> nata

Just use your result at the top, but use 10.^a and 10.^b instead of a and b:

IDL> plot, alog10(findgen(n) * (10.^b - 10.^a) / (n - 1.) + 10.^a)

Mike
--
Michael Galloy
www.michaelgalloy.com
Modern IDL, A Guide to Learning IDL: http://modernidl.idldev.com
Research Mathematician
Tech-X Corporation

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[Message index]

		Re: how to create a LOG array from A to B By: Mark Piper on Fri, 13 January 2012 13:32
		Re: how to create a LOG array from A to B By: natha on Thu, 12 January 2012 13:43
		Re: how to create a LOG array from A to B By: manodeep@gmail.com on Thu, 12 January 2012 13:50
		Re: how to create a LOG array from A to B By: natha on Thu, 12 January 2012 13:41
		Re: how to create a LOG array from A to B By: natha on Thu, 12 January 2012 12:05
		Re: how to create a LOG array from A to B By: Michael Galloy on Thu, 12 January 2012 11:52

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