CPU efficiency: formula node or Labview generic operations?

[Gabi1]

Hello,

 ihave a big program which requires to calculate a lot of analog ramps with 10us step size, for a time of about 20sec. it leads to a calculation time wich reaches fast the few seconds!

i use a formula node in which the ramp function is defined. i could use all normal labview operations if the operation appear to be faster.

i have looked at the usual memory allocations, and could not find a big flaw

[altenbach]

Don't forget that there is also a "ramp pattern" tool in the signal generation palette.

I always like the experimental approach: The best advice would be to wire up a few alternative version and compare speed and memory use in a small benchmarking application.

How many such ramps are in memory at any given time? Does your code generate extra data copies? What is the datatype? An 20M Sample ramp of DBL is 160MB!

[Gabi1]

thanks for your tips.

will do so. btw i sent this thread again with a vi attached. (somehow it appeared as a separate question, sorry about that).

[altenbach]

Also, can you be a bit more specific on the "ramp" you are trying to generate.

A linear ramp with your specifications would require a D/A converter better than 24bits. What kind of hardware do you have?

[altenbach]

OK, the program is posted elsewhere, so let's continue in the other thread:

http://forums.ni.com/ni/board/message?board.id=170&message.id=244504#M244504