[MOAB-dev] MOAB search tag range

[Steve Balderrama]

Thanks for the response, I'll try the tag_iterate then.

From: Grindeanu, Iulian R. [mailto:iulian at mcs.anl.gov]
Sent: Friday, May 29, 2015 10:22 AM
To: Steve Balderrama; moab-dev at mcs.anl.gov
Subject: RE: MOAB search tag range

There is no mechanism for that. I assume you are talking about dense tags, not sparse tags.
If sparse tags, you will just have to retrieve one by one the tag values, with tag_get_data(()

I think the most efficient way is to use tag_iterate over your elements of interest (if dense)
By using tag_iterate, you will access tag values directly in memory, no copying involved
You should return either a range or a standard vector, depending on how broken your output  sequence will be

(so if your output will be hex1-10, hex 101-120, it is better to have a range; if it is hex1, hex 5, hex 11, (very sparse), it is better to output a vector)

so your code could look like this (look in Interface.hpp comments)

Range output_range;

Range::iterator iter = ents.begin();
 while (iter != ents.end()) {
     int count;
     // get contiguous block of tag dat
     void* ptr;
     err = mb.tag_iterate( tag, iter, ents.end(), count, ptr );
     if (err) { ... }
    // do something with tag data
     // assume your tag is type double
     double *dptr = ptr
    for (int j=0; j<count; j++, dptr++)
     if (*dptr<0.25 && *dptr > 0.75)
   {
      EntityHandle interesting_element = (*iter+j);
      output_range.insert( interesting_element  )

   }
      // advance to next block of data
     iter += count;
  }
________________________________
From: moab-dev-bounces at mcs.anl.gov<mailto:moab-dev-bounces at mcs.anl.gov> [moab-dev-bounces at mcs.anl.gov] on behalf of Steve Balderrama [sbalderrama at eagle.org]
Sent: Friday, May 29, 2015 9:58 AM
To: moab-dev at mcs.anl.gov<mailto:moab-dev at mcs.anl.gov>
Subject: [MOAB-dev] MOAB search tag range
Is there a direct function in MOAB for searching for a range of tag values, for example, looking for elements with a tag within a numeric range such as > .25 and < .75, or something similar?

If not, what is the most efficient mechanism to do this in MOAB?

Thanks.


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