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Re: Compare two variables [message #61277 is a reply to message #61276]

Mon, 14 July 2008 04:57

ben.bighair
Messages: 221
Registered: April 2007

Senior Member

On Jul 14, 4:09 am, Joost Aan de Brugh <joost...@gmail.com> wrote:
> Hello Dave,
>
>> hi Joost
>> but i work with float data. as you said this metheod works for
>> integer. could we modify it to work for non integer data?
>> Cheers
>> Dave
>
> That is a pity. But isn't that dangerous in any case. If A and B are
> floats then the expression A eq B is not reliable because of
> continuous rounding. It may still be reliable if absolutely no
> arithmetic is involved.
>
> The compression trick does not work for floats, because of the degree
> of infinity.
>
> Maybe a two-step filtering is apropriate
>
> idx1 = Where(B[2,*] = A[0,j]) ; in for-loop or with the matrix-trick I
> did with DA and DB.
> inbetweenresult = B[*,idx1]
>
> idx2 = Where(inbetweenresult[3,*] = A[1,j]) ; in for-loop or with the
> matrix-trick I did with DA and DB.
> result = inbetweenresult[*,idx2]

Hi,

It doesn't seem to me that Dave has provided sufficient information.
I think the question was not fully fleshed out so it is hard to
provide helpful answers.

For example, is it possible that the coordinates could be temporarily
coerced into integers with losing unique pairings? If that is that
case then he can use the method described by Joost. Or, here is
another tack, is there a certain granularity (or precision) to the
coordinates - measured to the nearest tenth or hundreth perhaps? If
that is the case then he could simply promote the coordinates by
multiplying by 10 (or 100 or whatever) and then convert to integer.

Cheers,
Ben

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[Message index]

		Re: Compare two variables By: d.poreh on Mon, 14 July 2008 06:00
		Re: Compare two variables By: ben.bighair on Mon, 14 July 2008 04:57
		Re: Compare two variables By: Joost Aan de Brugh on Mon, 14 July 2008 01:09
		Re: Compare two variables By: Sven Geier on Sat, 12 July 2008 12:54
		Re: Compare two variables By: d.poreh on Sat, 12 July 2008 06:18
		Re: Compare two variables By: d.poreh on Fri, 11 July 2008 10:14
		Re: Compare two variables By: Jean H. on Fri, 11 July 2008 08:49
		Re: Compare two variables By: Joost Aan de Brugh on Fri, 11 July 2008 08:41

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