Charm++ parallel programming system

[Sam White <white67 AT illinois.edu>]

[reductiontarget] entry methods are not type-safe, and you can't overload them currently. We have a related issue to this open right now: https://charm.cs.illinois.edu/redmine/issues/1700

There is no difference between the following:
    1. entry [reductiontarget] void minstat(double min[n], int n);
    2. entry [reductiontarget] void minstat(int n, double min[n]);

-Sam

On Thu, May 3, 2018 at 3:16 PM, Jozsef Bakosi <jbakosi AT lanl.gov> wrote:

Cool, thanks, Sam. Both versions work.

However, I am now curious about the 2nd one: If I can contribute a std::vector
with a size determined at runtime to a reduction, how can you guys find the
right overload at compile-time for the target using the 2nd version? That seem
fishy to me, or at least not type-safe.

In particular, it also appears to work with

     entry [reductiontarget] void minstat(double min1, double min2, double min3);

And if I use min3 I risk formatting the internet? ;-)

Another question: I have so far been using

     entry [reductiontarget] void minstat(double min[n], int n);

but

     entry [reductiontarget] void minstat(int n, double min[n]);

also works. Is there a reason to prefer one over the other? Are they just
overloads of the same?

J

On 05.03.2018 14:45, Sam White wrote:
> The [reductiontarget] entry method still needs to take a C-style array of N
> doubles as its argument or separate doubles, despite now being able to
> contribute a std::vector directly to the reduction. So it should like this:
>
>     entry [reductiontarget] void minstat(int n, double min[n]);
>
> or this:
>
>     entry [reductiontarget] void minstat(double min1, double min2);
>
>
> We'll update our documentation to make this clear.
>
> -Sam
>
> On Thu, May 3, 2018 at 2:31 PM, Jozsef Bakosi <jbakosi AT lanl.gov> wrote:
>
> > Hi folks,
> >
> > I'm trying do a reduction on a std::vector:
> >
> > std::vector< double > min{ 1.0, 1.0 };
> >
> > contribute( min, CkReduction::min_double,
> >   CkCallback(CkReductionTarget(Target,minstat), target) );
> >
> > with
> >
> > chare Target {
> >   entry [reductiontarget] void minstat( std::vector< double > d );
> > }
> >
> > class Target : public CBase_Target {
> >   public:
> >     void minstat( std::vector< double > d ) {
> >        ...
> >     }
> > }
> >
> > However, I get:
> >
> > 161: ------------- Processor 0 Exiting: Called CmiAbort ------------
> > 161: Reason: Unhandled C++ exception in user code.
> > 161:
> > 161: [0] Stack Traceback:
> > 161:   [0:0] CmiAbortHelper+0xc1  [0x7fffe75ccfc1]
> > 161:   [0:1] +0x7148  [0x7fffe75ca148]
> > 161:   [0:2] +0x17cb88  [0x7fffe7d59b88]
> > 161:   [0:3] +0x17cb69  [0x7fffe7d59b69]
> > 161:   [0:4] +0x22763  [0x7fffe5536763]
> > 161:   [0:5] +0x25516  [0x7fffe5539516]
> > 161:   [0:6] +0x254af  [0x7fffe55394af]
> > 161:   [0:7] std::__1::__vector_base_common<true>::__throw_length_error()
> > const+0x44  [0x7fffe57e00a4]
> > 161:   [0:8] std::__1::vector<double, std::__1::allocator<double>
> > >::__append(unsigned long)+0x139  [0x5aaf59]
> > 161:   [0:9] std::__1::vector<double, std::__1::allocator<double>
> > >::resize(unsigned long)+0x7b  [0x5aa9db]
> > 161:   [0:10] void PUP::operator|<double>(PUP::er&,
> > std::__1::vector<double, std::__1::allocator<double> >&)+0x44  [0x5aa884]
> > 161:   [0:11] _ZN3PUP6detailorINSt3__16vectorIdNS2_9allocatorIdEEEEEEvRNS_
> > 2erERNS0_21TemporaryObjectHolderIT_Xsr3std16is_constructibleINS_
> > 11reconstructESA_EE5valueEEE+0x1d  [0x5b204d]
> > 161:   [0:12] inciter::CkIndex_Transporter::_call_redn_wrapper_minstat_marshall11(void*,
> > void*)+0x80  [0x7ffff649d6f0]
> > 161:   [0:13] CkDeliverMessageFree+0x41  [0x7fffe7d73b21]
> > 161:   [0:14] +0x19763b  [0x7fffe7d7463b]
> > 161:   [0:15] +0x19ecfb  [0x7fffe7d7bcfb]
> > 161:   [0:16] +0x199496  [0x7fffe7d76496]
> > 161:   [0:17] _processHandler(void*, CkCoreState*)+0x245  [0x7fffe7d75a85]
> > 161:   [0:18] CmiHandleMessage+0x97  [0x7fffe735faa7]
> > 161:   [0:19] CsdScheduleForever+0xc4  [0x7fffe735fdd4]
> > 161:   [0:20] CsdScheduler+0x1a  [0x7fffe735fafa]
> > 161:   [0:21] +0x9c91  [0x7fffe75ccc91]
> > 161:   [0:22] ConverseInit+0x6c3  [0x7fffe75cc543]
> > 161:   [0:23] main+0x45  [0x7fffe825e755]
> > 161:   [0:24] __libc_start_main+0xe7  [0x7fffe4d45a87]
> > 161:   [0:25]   [0x4bd00a]
> >
> > I also tried with
> >   entry [reductiontarget] void minstat( const std::vector< double >& d );
> > and
> >     void minstat( const std::vector< double >& d ) {
> >
> > yielding the same problem. Can someone enlighten me on how to reduce a
> > std::vector?
> >
> > Thanks,
> > Jozsef