> Regarding the strided get call in my previous message, what does each
> "array_get" call mean semantically? For example,
> the __primitive("array_get",
> src, arrSection.myElems._value.getDataIndex(myFollowThis.low)). I
> understand vaguely that this call determines the source pointer at which to
> start from when communicating remote data, but that is about it. If I
> wanted to start from another source pointer (some offset from the original
> source pointer) that is determined dynamically at runtime, how might I do
> this? Any further help in understanding this would be appreciated. Here is
> the full code portion that might be useful in answering my question: 


Just use a variable, for example, to use another offset at the source you can 
use:

        var origin=100:int;
        var lmin=5:int;

__primitive("array_get", src,
arrSection.myElems._value.getUnshiftedDataIndex(origin-lmin)),

Then you can change the values of origin and lmin in different loops.

Also remember that in the first line you must also use the Unshifted version of 
getdataindex :
 __primitive("array_get", dest, buf._value.getUnshiftedDataIndex(1)),

Greets,

Rafael

> var buf: [1..bufsize] this.eltType;
> var dest = buf._value.theData;
> const src = arrSection.myElems._value.theData;
> const rid=arrSection.locale.id;
> var dststr=dstStride._value.theData;
> var srcstr=srcStride._value.theData;
> var cnt=bounded_count._value.theData;
> //copy remote data to local buffer 
> __primitive("chpl_comm_get_strd",
> __primitive("array_get", dest, buf._value.getDataIndex(1)),
> __primitive("array_get",dststr,dstStride._value.getDataIndex(1)), 
> rid,
> __primitive("array_get", src,
> arrSection.myElems._value.getDataIndex(myFollowThis.low)),
> __primitive("array_get",srcstr,srcStride._value.getDataIndex(1)),
> __primitive("array_get",cnt, bounded_count._value.getDataIndex(1)),
> stridelevels);
> 
> Aroon Sharma
> University of Maryland, Class of 2015
> M.S. Computer Engineering
> (301) 908-9528
> 
> 
> 
> On Wednesday, January 22, 2014 3:31 PM, Rafael Larrosa Jiménez
> <[email protected]> wrote:
> 
> Hi,
> 
> > Hi everyone,
> > 
> > I am running into bugs in a multi-locale Chapel program and came across
> > the
> > following in $CHPL_HOME/STATUS:
> > 
> > - The --gdb flag is only supported for single-locale platforms that
> >
> >   support gdb.  Please ask us for help if you want to debug a
> >   multilocale program.
> >
> > That being said, I would like to know what options I have to debug a
> > multi-locale Chapel program and how to use these options.
> > 
> > The specific problems I think I am encountering in my multi-locale program
> > have to do with the chpl_comm_get_strd and chpl_comm_put_strd
> > communication
> > calls. I want to split a single get or put call into multiple calls to
> > conserve memory on a locale. The following code shows a single call
> > (assuming parameters are declared beforehand):
> > 
> > //copy remote data to local buffer
> > __primitive("chpl_comm_get_strd",
> > __primitive("array_get", dest, buf._value.getDataIndex(1)),
> > __primitive("array_get",dststr,dstStride._value.getDataIndex(1)),
> > rid,
> > __primitive("array_get", src,
> > arrSection.myElems._value.getDataIndex(myFollowThis.low)),
> > __primitive("array_get",srcstr,srcStride._value.getDataIndex(1)),
> > __primitive("array_get",cnt, count._value.getDataIndex(1)),
> > stridelevels);
> 
> If you are using the trunk, one problem can be that you need to use
> getUnshiftedDataIndex in the pointers to source and destination instead of
> getDataIndex.
> 
> Also I have found quite useful to activate the bounds checker for the
> programs with:
> --bounds-checks --local-checks --nil-checks --debug
> 
> And it can help also to wrap those primitive calls with :
> 
> startVerboseComm();
> __primitive("chpl_comm_get_strd",....
> stopVerboseComm();
> 
> 
> Hope this helps,
> 
> Rafael
> 
> > with the following semantics:
> > 
> > __primitive("chpl_comm_get_strd",
> > pointer to source,
> > source strides,
> > remote locale id,
> > pointer to destination,
> > destination strides,
> > copy length,
> > number of dimensions
> > );
> > 
> > Any suggestions or documentation relating to either of these topics would
> > be helpful.
> > Aroon Sharma
> > University of Maryland, Class of 2015
> > M.S. Computer Engineering
> > (301) 908-9528
-- 
Rafael Larrosa Jiménez
Centro de Supercomputación y Bioinformática - http://www.scbi.uma.es
Universidad de Málaga

EMAIL: [email protected]          Edificio de Bioinnovación
TELEF: + 34951952788            C/ Severo Ochoa 34
FAX  : +34951952792                     Parque Tecnológico de Andalucía
                                                29590 Málaga (SPAIN)


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