how do I subract 1d of a 2d array?

[Phil_T]

I have 2 sets of 2d array of numbers and I would like to subract only the second dimension of numbers and leave the data alone in the first dimension. Any Idea how to go about this? here is an example of what my arrays look like

1.5    

[Phil_T]

my 2 sets of arrays look like this:

Set 1

1.5  2.5  3.5

10   20   30

Set 2

1.5  2.5  3.5

  1     2    3

What I want to do is subract the second dimension of set 2 from set 1 to get the following resultant 2d array

Resultant array

1.5  2.5  3.5

  9   18   27

Thanks,

Phil

[Anthony_Wong]

Hi Phil T,

Attached below, I have included a VI that I think achieves what you describe. When you run the program, the desired calculations you are seeking are carried out and placed into the "Resultant array".

Be aware that I am still relatively new to LabVIEW and that there may be a simpler way to achieve your desired result with less coding.

Message Edited by Anthony_Wong on 06-27-2006 10:25 AM

[DavidJCrawford]

Another option. You can work with 1D arrays then build it up again

David

Message Edited by David Crawford on 06-27-2006 04:26 PM

[Sarah_Coleman_NIUK]

Message Edited by SarahB on 06-27-2006 10:28 AM

[Will.D]

Here's a slightly less bulky method.  The principle is exactly the same as Anthony's, however it uses the fact that the basic functions (in this case subtract) are so flexible.

Edit: Oops, while I was creating that VI there were a few others posted.

Message Edited by Novatron on 06-27-2006 11:32 AM

[Anthony_Wong]

I suspected that the subtract function was flexible and edited my post to reflect that (i.e. rather than extracting the elements individually, just simply subtract the two subarrays).

Thanks for the tip though Novatron.

[agill]

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@Anthony_Wong wrote:
I suspected that the subtract function was flexible and edited my post to reflect that (i.e. rather than extracting the elements individually, just simply subtract the two subarrays).

Thanks for the tip though Novatron.

---

This flexibility is called "polymorphism".  I think most if not all arithmetic (numeric functions) operators are polymorphic.  It's a handy thing to know about.

If you encounter a non-polymorphic function, and you want to apply it to a whole array you have to index into the datatype, somehow (usually using a for or while loop with indexing enabled, and iterate the whole length of the array),

[altenbach]

It is often easier to use autoindexing. Here's an alternative approach that does not use any explicit index array functions. 😄

Message Edited by altenbach on 06-27-2006 09:27 AM

[Phil_T]

Thanks to all who helped