How to average every certain lines in a 2D array

[scoccer]

For example, if I have a 1000 by 300 2-D array and I want to average every 3 lines in this array to make it a 1000 by 100 array. How can I do this? Thanks!

[GITA_A]

Hi,

     Use Delete from array,specify the dimension to it and then average.

[RavensFan]

Decimate the array into 3 arrays.  You may or may not need to transpose it before that depending on the layout of your rows.  Add the 3 arrays together.  Divide by 3.

[altenbach]

Decimate only works for 1D array, so this needs a bit more work. Still, it should not be too difficult. 🙂

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scoccer wrote:
For example, if I have a 1000 by 300 2-D array and I want to average every 3 lines in this array to make it a 1000 by 100 array. How can I do this? Thanks!

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Is a "line" a column or a row?

(And no AutoTEX, "delete from array" makes no sense at all for this.)

[scoccer]

Sorry I am not familiar with arrays, do I need to use a loop or something like reshape array to make it a 1d array to use the decimate? Thanks!

In  this example,  a "line" is a column.

[Santhosh M]

Hi 

Check the attachments

[altenbach]

OK, here's a simple way to do this (LabVIEW 8.0)

Message Edited by altenbach on 11-03-2008 09:05 PM

[altenbach]

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Santhosh M wrote:

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This is extremely inefficient, because the array in the shift register changes constantly, forcing new memory allocations with every iteration. This will be orders of magnitudes slower than a solution that operates in-place.

I would strongly recommend against this solution. 🙂

[RavensFan]

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altenbach wrote:

OK, here's a simple way to do this (LabVIEW 8.0)

Message Edited by altenbach on 11-03-2008 09:05 PM

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That's exactly what I was thinking, except I didn't realize the decimate array wouldn't work on the 2-D array, and I wasn't on a LV computer at the time to work up the example.

[scoccer]

Thanks very much for all your advices. It works great!