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Topic: Indexing
Replies: 4   Last Post: Mar 7, 2013 2:24 PM

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dpb

Posts: 8,115
Registered: 6/7/07
Re: Indexing
Posted: Mar 6, 2013 1:02 PM
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On 3/5/2013 9:16 PM, Eric wrote:
> Hi,
>
> I know I should be able to figure this out based on previous posts, but
> I still cannot find the correct solution. Within matrix A (nx1 matrix),
> I want to find the first instance that a value BW is 10 units less than
> BW--I'll call this value DROP. It is not a min or max value. I am just
> trying to index points on a force waveform so I can eventually integrate
> the area between points.
>
> Specifically:
> BW= 650; DROP = BW-10;
> [event1,ind1] = A(DROP,1);
>
> Using this, I get an error 'Indexing cannot yield multiple results'.
> I tried using find but all the values will be positive numbers.

...

ix=find(A==DROP,1); % the first index
A(ix) % the value at that index

NB: If A is floating point and not integer-value, the problem of exact
comparisons for floating point values may rear its head...the values
you've shown are integers well withing DP resolution so will be stored
exactly, but that's not necessarily so in general of course.

--




Date Subject Author
3/5/13
Read Indexing
Eric
3/5/13
Read Re: Indexing
Derek Goring
3/6/13
Read Re: Indexing
dpb
3/7/13
Read Re: Indexing
Eric
3/7/13
Read Re: Indexing
dpb

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