How to increment an element in an array and put it back in the same array?

[Benoit_Provost]

I have an array of values generated by another part of my program. My goal is to count the number of occurences for each integer value in the array and put these values in a new array. This new array will be a histogram of the input array. My approach is to do auto-indexing with a for loop. In the loop I use a "index array" to get the current value of the histogram array and a "replace array subset" to update the array element with "current+1". The problem is that when I wire the output of the "replace array subset" VI back to its input, I get a wire error. I guess I cannot wire it like that, but what should I do? Is there a completely different approach to do this that
is more elegant?
Thanks for your help!
Benoit

[Doug (CapeFl)]

All sounds good until you wire the output of the "replace array subset" VI back to its input. At that point, could you simply feed your integer values into a totally new array using the "index array" VI? In fact, the elements stored into your new array could come directly off your initial array of values, where values checked for integer (using the "quotient & remainder" VI, where a remainder of 0 = integer) would be the integer elements for your new array. I'm sure there are many ways to do what your working on. Good Luck!

[Brian_Vibert]

Why not use the histogram.vi in functions>>mathmatics>>probability and statistics?

[Benoit_Provost]

I did not even know there was a histogram function. I will try it soon. But I tried the shift register approach and it works fine. Thanks!
Benoit

[Ben]

Hi Benoit,

I believe the thing that's missing is a shift register.

Right-click on the edge of your "For loop" and select add shift register.
Wire an initialized array to the shift register left terminal before entering the "for loop". Wire from this same terminal (inside the loop) as the source of the info used in your "index array" and replace array. The results of these two operations (just the way you are doing it now) gets wired to the "right terminal" of the shift register (inside the loop).

What ever you stuff into the right terminal, gets returned via the left terminal on the next iteration of the loop. When the loop is done, your final array of counts can be accessed by wiring from the "right terminal" (outside the loop).

Ben

[Benoit_Provost]

I spent some time yesterday trying the shift register approach and now it works perfectly! Thanks for the hint!
Benoit

[AndyBE]

HI! I have quite the same problem... An Array should present how often a die fell on a special number. Array with 6 elements representing the 6 possible numbers. Came to the same problem with backwires. Havn't got into the shift register thing up to now. Maybe somebody could help me on that. And is there really no possibility to de- or increment a element of a Array directly?
maybe somebody could provide examples?
Thanks

[Ben]

YOu must index out the previous count,
increment it
and use replace array element to put the updated value where it belongs.

Use your "die value" minus 1 as an index into your six element array.

Ben

[AndyBE]

Thanks.. somehow i got it to work.
ANDY