On 31 Aug 2009, at 9:44 AM, Igor Peshansky wrote:
> Jim LaGrone <jlagr...@cs.uh.edu> wrote on 08/31/2009 10:20:29 AM:
>
>> I spoke too soon. It compiled but didn't run. Still have the
>> BadPlaceExeption. This is the code:
>>
>> //declared as Class members
>> var regionS: Region{rank==2};
>> var distS: Dist{rank==2};
>> var S: Array[Complex](distS);
>>
>> //code from member method
>> regionS = [0..N-1, 0..Mc-1];
>> distS = Dist.makeBlock(regionS,0);
>>
>> S = Array.make[Complex](distS,
>> (val (i,j):Point) => new Complex ( real(i*Mc+j), image(i*Mc+j) )
> );
>
> Jim,
>
> See my comments regarding fields vs. local variables, and static vs.
> instance methods. If real() and image() are instance methods, they
> will be invoked via "this", which lives in place 0. Also, if Mc is
> an instance field, it will also live in place 0. The initializer
> essentially runs in an ateach loop, so the same restrictions apply.
tmp_fs_real and tmp_fs_image are Rails[Double].
val real = tmp_fs_real;
val image = tmp_fs_image;
val Mc_tmp = Mc; //just made this change
val N_tmp = N; // and this one
regionS = [0..N_tmp-1, 0..Mc_tmp-1];
distS = Dist.makeBlock(regionS,0);
S = Array.make[Complex](distS,
(val (i,j):Point) => new Complex ( real(i*Mc_tmp+j), image
(i*Mc_tmp+j) ) );
>> I'm still confused about the number of places. It shows 4 places
>> printing NativeRuntime.MAX_PLACES on my dual core machine. I'll
>> attach
>> output from execution.
>>
>> Jim
>
> X10 will not automatically compute the optimal number of places --
> you have to tell it how many places to use. For the Java backend
> the default is 4 places, regardless of the number of actual cores.
> For the C++ backend it's however many processes you spawn (runx10
> will only spawn one).
How do I change the number of places? This seems to execute with C++
backend.
>
> Hope this helps,
> Igor
>
>> [attachment "exec.out" deleted by Igor Peshansky/Watson/IBM]
>>
>> On 28 Aug 2009, at 8:29 PM, Josh Milthorpe wrote:
>>
>>> If I correctly understand the intent, you're trying to initialize
>>> each element of S : Array[Complex] based on some values in the real
>>> and image rails. However I don't think that's what the above code
>>> achieves.
>>>
>>> The outer loop iterates over all places included in distS. The
>>> inner loop iterates over every point in the region of S. Because
>>> distS is a block distribution over all places, this means that an
>>> activity will be started at each place, and each activity will
>>> attempt to assign to every element of S - including those elements
>>> that reside at other places. I suspect that this is the cause of
>>> the BPE.
>>>
>>> (As an aside, S is not distributed, because distS is not used in the
>>> initializer. To make it distributed, use
>>> distS = Dist.makeBlock(distS,0);
>>> rather than
>>> distS = Dist.makeBlock(regionS,0);
>>> )
>>> You could initialize S in a single statement using an Array
>>> initializer function, something like:
>>>
>>> S = Array.make[Complex](distS, (val (i,j): Point) => new Complex
>>> (real(i*Mc+j), image(i*Mc+j)));
>>
>> This is what I was looking for but couldn't make it work. I don't
>> know
>> what I had before, but this works. Thanks!
>>
>>>
>>> BTW is the use of "image" rather than "imaginary" an American vs.
>>> British thing? I haven't heard this term used before.
>>
>> I'm porting a benchmark someone else wrote in C. I'm just using the
>> same identifiers. Personally, I would have used "imag".
>>
>> Jim
> --
> Igor Peshansky (note the spelling change!)
> IBM T.J. Watson Research Center
> XJ: No More Pain for XML's Gain (http://www.research.ibm.com/xj/)
> X10: Parallel Productivity and Performance (http://x10.sf.net/)
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