Charm++ parallel programming system

[Matthias Diener <mdiener AT illinois.edu>]

Hi John,

'index' is indeed a member of the CkArrayIndex base class
(CkArrayIndexBase) that stores the actual index data.
I think the manual (and the sample code) are not very clear on this
index element, I'll see if I can update them in this regard.

Regards,
Matt

On 14 June 2017 at 10:43, Mitchell, John A 
<jamitch AT sandia.gov>
 wrote:
> Thanks Matt.
>
> That does seem like it may be the issue -- the example code: 
> examples/charm++/hello/fancyarray/hello.C
> uses that method.
>
> BTW: where does 'index' come from? ( idx = new(index) LeafId(f))
>
> Is that a member in CkArrayIndex like 'nInts'?
>
> Thanks again.  I need to see if this will work for me.
> John
> ________________________________________
> From: Matthias Diener 
> <mdiener AT illinois.edu>
> Sent: Tuesday, June 13, 2017 6:32 PM
> To: Mitchell, John A
> Cc: 
> charm AT lists.cs.illinois.edu
> Subject: Re: [EXTERNAL] Re: [charm] user defined array indices
>
> Hi John,
>
> I did some more tests and I believe I found the problem.
>
> In general, there are no issues with the following way to insert
> indices (based on a short-lived "f" object):
>
>     for (int i=0; i<nElements; i++) {
>       LeafId f(i,0);
>       arr[f].insert();
>     }
>
> However, the CkArrayIndexLeafId class needs to store the actual index 
> object:
>
> class CkArrayIndexLeafId :public CkArrayIndex {
>   LeafId *idx;
>    public:
>
>   CkArrayIndexLeafId(const LeafId &f)
>   {
>     idx = new(index) LeafId(f);
>     nInts=2;
>   }
> };
>
> When removing the line that allocates "idx", the program crashes in
> the way you described in your initial message. Might this be the issue
> you saw?
>
> Regards,
> Matt
>
> On 13 June 2017 at 17:00, Mitchell, John A 
> <jamitch AT sandia.gov>
>  wrote:
>> Matt,
>>
>> Thanks for you efforts.
>>
>> The full code is too complicated to post.  I can try and create a simpler 
>> example using the LeafId class I did post to see if it will still have 
>> that problem.
>>
>> Can you say anything about the difficulties you are having?  Did you try 
>> and use my user index LeafId class in your effort and had no problem?  
>> What causes that error to occur?  How are user indices unique?
>>
>> Thanks,
>> John
>> ________________________________________
>> From: Matthias Diener 
>> <mdiener AT illinois.edu>
>> Sent: Tuesday, June 13, 2017 3:49 PM
>> To: Mitchell, John A
>> Subject: [EXTERNAL] Re: [charm] user defined array indices
>>
>> Hi John,
>>
>> I am having difficulties to replicate your example. Could you please
>> post the full code?
>>
>> Thanks,
>> Matt
>>
>> On 6 June 2017 at 19:27, Mitchell, John A 
>> <jamitch AT sandia.gov>
>>  wrote:
>>> Hi,
>>>
>>>
>>> I am having trouble understanding how to use 'user defined array indices';
>>>
>>> I am using indices to insert into an array.  after all insertions I use
>>> 'array.doneInserting'
>>> array [LeafId] Leaf { ... };
>>> My indexing class is below;
>>> Can temporary (short lived) LeafId instances be used to index.
>>> What I don't understand is what makes each user index unique?
>>> Code below errors out with:
>>> ------------- Processor 0 Exiting: Called CmiAbort ------------
>>> Reason: Cannot insert array element twice!
>>>
>>> thanks,
>>>
>>> John
>>>
>>>
>>> // Insert leaves using indices defined below.  Note 'id' only exists 
>>> insides
>>> braces and will disappear quickly since its a temporary variable.
>>>
>>> {
>>>
>>> LeafId id(level+1,path+1);
>>> leaves[id].insert(right_tree_size,right_points,thisProxy,span_right_pup);
>>>
>>> }
>>>
>>>
>>> // My user defined indexing class
>>>
>>> class LeafId {
>>>
>>>    private:
>>>       ordinal_type level, path;
>>>    public:
>>>
>>>       LeafId(ordinal_type l, ordinal_type p) : level(l), path(p) { }
>>>
>>>       bool is_left() const { return 0==path%2; }
>>>       bool is_right() const { return 1==path%2; }
>>>
>>>       ordinal_type cardinality() const {
>>>          ordinal_type id=1;
>>>          for(int i=1;i<=level;i++)
>>>             id*=2;
>>>          return id+path;
>>>       }
>>>
>>> };
>>>
>>> class CkArrayIndexLeafId :public CkArrayIndex {
>>>    public:
>>>       CkArrayIndexLeafId(const LeafId& l) {
>>>          nInts=2;
>>>       }
>>> };
>>>