RE: How to perform Loop in VDCT

["Mooney, Tim M." <mooney@aps.anl.gov>]

Hi Priya,

I would do this with a subroutine record or an SNL program.  Yes, you can make loops in EPICS database, but I would not implement your example in that way.

If I had to do this kind of stuff in a database - for example, if I had to be able to write the _expression_ at run time - I'd use an acalcout record, and part of the _expression_ for your example would look like this:

sum(100*(ix%2)[0,9])+sum(-100*(!(ix%2))[0,9])

where, for example
    ix is (0,1,2,3,...)
    ix%2 is (0,1,0,1,...)
    ix[0,9] is (0,1,2,3,4,5,6,7,8,9,0,0,0,...)

If you're really desperate for an explicit loop, the acalcout and scalcout records have the "until" function:

    a:=0;b:=0;k:=until(a:=a+1.3;b:=b+1;b>=9);a

which is arcane, and difficult, and merely implements this:
    a=0;
    for (b=0; b<10; b+=1) {
        a += 1.3;
    }

If you want to process records in a loop, on the other hand, I second Bob's advice, and note that the calcout record has more help for conditionally executing a link.  Finally, the sscan record does loops, and I've used it with calc records to make 2D arrays of sample data.

Tim Mooney (mooney@aps.anl.gov) (630)252-5417
Software Services Group (www.aps.anl.gov)
Advanced Photon Source, Argonne National Lab

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From: tech-talk-bounces@aps.anl.gov [tech-talk-bounces@aps.anl.gov] on behalf of priya tiwari [tiwaripriya013@gmail.com]
Sent: Thursday, November 13, 2014 12:51 AM
To: tech-talk@aps.anl.gov
Subject: How to perform Loop in VDCT

How to perform "for loop" in VDCT?

I want to try this  program in VDCT .

float avg;

int sum=0;int i,j;

for (i=0;i<20;i++)
{

for(j=0;j<10;j++)
{

if(j%2==0)
{

sum=sum+100;

}

else
{

diff=-100;

}

avg=(sum+diff)/10;

printf("%f",avg);

}

}

what type of record and field is used for this program in VDCT?

please provide me solution?

Thanks in advance......