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Re: Beginner: Oplot line t^(-5/3) [message #82033 is a reply to message #82032]

Mon, 12 November 2012 08:35

Helder Marchetto
Messages: 520
Registered: November 2011

Senior Member

On Monday, November 12, 2012 5:20:31 PM UTC+1, Charlie Paul D'auria wrote:
> Hi there!
>
>
>
> Please bear in mind that I am a complete IDL beginner so excuse any foolishness!
>
>
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> I have managed to plot an XY graph with data plots.
>
>
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> My problem lies with my next stage: I need to generate a line of gradient t^(-5/3) (then use oplot over my data).
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> I get the error 'Attempt to subscript T with I is out of range.' and when I type print,line I only get one value for my line...
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> Here is some code I was provided with as a guide, which I have modified slightly:
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> line=dblarr(9999)
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> n=1E-4
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> t=dblarr(9999)
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> for i=0,9999 do begin
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> t(i)=i
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> line=n*t(i)^(-5./3.)
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> endfor
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> I have used 9999 as 1E+5 was apparently too large, or something..
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> Any help would be much appreciated!!
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> Charlie

I would do it like this (using double precision):

n=1d-4
t=dindgen(9999)+1d ; starting from t=0 makes no sense, start from 1
line=n*t^(-5d /3d)
window, xsize=600, ysize=400 ; create a window for display
plot, t, line, /ylog ; plot in y-log coordinates

Avoid loops, unless strictly necessary.

Cheers,
Helder

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[Message index]

		Re: Beginner: Oplot line t^(-5/3) By: Craig Markwardt on Mon, 12 November 2012 12:25
		Re: Beginner: Oplot line t^(-5/3) By: David Fanning on Mon, 12 November 2012 08:37
		Re: Beginner: Oplot line t^(-5/3) By: Helder Marchetto on Mon, 12 November 2012 08:35

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