bit array

[Timothy 123]

Hi,

I have an array in labview of u8 numerics. Each numeric is a bit (1 or 0). Each u8 numeric is a byte large, which for an array representing 100 bits would be 100 bytes = 800 bits (8 times as large). Is there a way to represent single bits (1 and 0's ) in labview efficiently.

Thank you,

-Tim

[RavensFan]

Does that mean a U8 true is 255 (all 1's) and a U8 false is 0 (all 0's)?

How about this?

Message Edited by Ravens Fan on 07-13-2007 11:04 PM

[RavensFan]

Or with a simpler alternative.

Message Edited by Ravens Fan on 07-13-2007 11:11 PM

Alternative #3 added.

Message Edited by Ravens Fan on 07-13-2007 11:15 PM

[RavensFan]

Message timed out before I got #3 in.

Message Edited by Ravens Fan on 07-13-2007 11:18 PM

[Timothy 123]

Hi,

I meant by 1 and 0 that the lsb (least significant bit) of each U8 numeric is 1 and 0. So we have in binary for each u8 element of the array 1 and 0.

Thank you for your reply,

Tim

[BillMe]

Even more simplified....

Message Edited by Bill@NGC on 07-13-2007 10:25 PM

[Odd_Modem]

LabVIEW 4.1 was the last version that stored an array of booleans in packed format. A boolean array now is an array of bytes so converting U8 to boolean only makes a copy of the data. You can use run length encoding or bit packing to compress the data but the both have access problems.

[Timothy 123]

Hi,

Are there functions in labview to do run lenght encoding and bit packing in labview, or would I have to implement these myself?

Thank you,

Tim

[mikeporter]

Really not so hard, just tell LV8 to treat the boolean array as though it were LV4...

Mike...

[Timothy 123]

Hi mikeporter,

Which version of labview are you using? I am using 8.2 and I only see a convert to 7.x in my unflatten to string, and flatten to string functions. I do not see the convert to 4.x on my functions. Also, I looked in this site

http://digital.ni.com/public.nsf/allkb/3B60483A50030258862565BC00733B89

and it says that in labview 4.x booleans are treated as 16-bit numerics which is more memory intensive than in newer versions of labview where a boolean is just a single byte (8 bits).

-Tim