array building

[Moschdschlotzer]

Hi,

i am doing a 4 channel measurement and puting this data into a 2D-Array. After this i am saving the data to hardisk. But often i need only channels 1 and 2, or 2 and 3 or only 1 and so on. So you see i have 16 possible combinations. To save disk space i have four selectors to mark the channels which should be saved. With this informations i would like to build one new array with only the information of the marked channels. First i thought that it is a very simple problem. But after thinking 2 days i am not sure anymore. I didn't find a way doing that. I think it's very tricky. Please help me!

regards

Jens

[mikeporter]

The way I woudl handle it is to write the code so it always saves the data that is returned from the DAQ hardware. To delete the unused channels, manipulate the list of channels that you are acquiring. I call this "supply-side" array manipulation...

Of course you can delete columns out of arrays, but depending upon the size of the array it can be very inefficient.

Mike...

[altenbach]

Shouldn't be too hard. Here's one simple possibility that should point you in the right direction.

(If your arrays are very big, there are a few additional tweaks to improve performance)

[Moschdschlotzer]

Thank you very much! It works great! My arrays are about 4 x 200.000 elements.

Message Edited by Moschdschlotzer on 06-13-2007 04:45 AM