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TOTAL function [message #86528] Fri, 15 November 2013 08:54 Go to next message
fd_luni is currently offline  fd_luni
Messages: 66
Registered: January 2013
Member
Hi

I want to calculate the error using the TOTAL function but I got very strange results:

The error is given by
error=||Aexact-Anoisy|| with matrix A=array[1,200]

where the ||.|| represents a norm.

I typed my code like this
SQRT( Total (AExact - Anoisy) ^2. )

Each time I run this I got very different and illogical number. The maximum value of an error isn't 1?

Many Thanks

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Re: TOTAL function [message #86530 is a reply to message #86528] Fri, 15 November 2013 09:22 Go to previous messageGo to next message
Mats Löfdahl is currently offline  Mats Löfdahl
Messages: 263
Registered: January 2012
Senior Member
Den fredagen den 15:e november 2013 kl. 17:54:44 UTC+1 skrev fd_...@mail.com:
> Hi
>
> I want to calculate the error using the TOTAL function but I got very strange results:
>
> The error is given by
> error=||Aexact-Anoisy|| with matrix A=array[1,200]
>
> where the ||.|| represents a norm.
>
> I typed my code like this
> SQRT( Total (AExact - Anoisy) ^2. )

You probably want to write this as SQRT( Total( (AExact - Anoisy)^2. ) ) so that you do the squaring before the summing.


> Each time I run this I got very different and illogical number. The maximum value of an error isn't 1?

That's difficult to answer without knowing anything about the contents of the two arrays.

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Re: TOTAL function [message #86552 is a reply to message #86530] Tue, 19 November 2013 01:59 Go to previous message
fd_luni is currently offline  fd_luni
Messages: 66
Registered: January 2013
Member
> You probably want to write this as SQRT( Total( (AExact - Anoisy)^2. ) ) so that you do the squaring before the summing.

Yes, this is what I want thanks a lot.

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