Re: [foxboro] HLBL Array Question

Peter:
Use a Circular Queue / Circular Array / Circular Buffer.
A good place to start:
http://en.wikipedia.org/wiki/Circular_buffer

-Mike

foxboro-bounce@xxxxxxxxxxxxx wrote on 05/15/2008 02:45:41 PM:

> Gentlemen (and Ladies)
> 
>         I have a large array size is 1440 (holds 24 hours worth of 1 min 
sa=
> mples)
> 
>         Every minute I want to update the 1 of the sample value and 
throw o=
> ut the oldest value.
> 
> Problem 1)
> 
>         Currently I am shuffling each value 1 at a time using this loop:
> ----------------------------
>       x :=3D 1;
>       SN01 :=3D "Preparing Array for new value ....";
>       WHILE (x < 1440) DO
>         ARHR[x] :=3D ARHR[x+1]; {* throw out arry position 1 and shuffle 
*}
>         x :=3D x + 1;
>       ENDWHILE;
>       ARHR[1440] :=3D RI01;     {* Load newest value into array position 
14=
> 40 *}
> ------------------------------
> 
> 
>         This works however just to shuffle the values takes almost 30 
secon=
> ds.
> 
>         Is there a quicker way to do this ?
>       Is there a way to copy array position [2] through [1440] to 
another a=
> rray using a single command ?
> 
> Problem 2)
> 
>         During the next step of my sequence I have to find the average 
for =
> the last 24 hours so I need to find the sum of the array then divide by 
144=
> 0. I use the following loop to find the sum:
> 
> ----------------------------
>    y :=3D 1;
>    SUM :=3D 0;
>    WHILE ( y < 1441 ) DO
>      SUM :=3D SUM + ARHR[ y ];
>      y :=3D y + 1;
>    ENDWHILE;
>    RO01 :=3D SUM/1440; {* 24 Hour rolling average *}
> ----------------------------
> 
>         Again it takes about 30 seconds just to find the sum of the 
array.
> 
>         Is there a quicker way to find the sum of an array?
> 
> 
> Thank You,
> 
> Peter Bruley
> 
> 
> 
> 
> 
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