Charm++ parallel programming system

["Hammond, Jeff R" <jeff.r.hammond AT intel.com>]

Can you do something evil where you extern pointer to storage and then 
declare it in a generic C++ file that will be preprocessed properly?

Obviously, may provoke the question “what is that terrible smell?” but I’ve 
seen far worse workarounds associated with legacy Fortran :-)

Jeff

From: "<Van Der Wijngaart>", Rob F 
<rob.f.van.der.wijngaart AT intel.com<mailto:rob.f.van.der.wijngaart AT intel.com>>
Date: Monday, September 29, 2014 at 9:55 AM
To: Phil Miller 
<mille121 AT illinois.edu<mailto:mille121 AT illinois.edu>>
Cc: Nikhil Jain 
<nikhil.life AT gmail.com<mailto:nikhil.life AT gmail.com>>,
 "Kunzman, David M" 
<david.m.kunzman AT intel.com<mailto:david.m.kunzman AT intel.com>>,
 Jeff R Hammond 
<jeff.r.hammond AT intel.com<mailto:jeff.r.hammond AT intel.com>>,
 "Mattson, Timothy G" 
<timothy.g.mattson AT intel.com<mailto:timothy.g.mattson AT intel.com>>,
 
"charm AT cs.illinois.edu<mailto:charm AT cs.illinois.edu>"
 
<charm AT cs.illinois.edu<mailto:charm AT cs.illinois.edu>>
Subject: RE: Global variables in Charm++

OK, it appears not to be the problem of running the preprocessor per se, but 
of having expressions in array dimensions. I replaced
  readonly double weight[(2*RADIUS+1)*(2*RADIUS+1)];
with
  readonly double weight[3+3+3];
and got another syntax error.
This looks like a pretty serious limitation to me. I am now required to do 
the array dimension computation for charmc and stuff that into the .ci file 
explicitly as a constant. This means running another script/preprocessor 
before I can run charmc.

Rob

From: Van Der Wijngaart, Rob F
Sent: Friday, September 26, 2014 3:49 PM
To: 'Phil Miller'
Cc: Nikhil Jain; Kunzman, David M; Hammond, Jeff R; Mattson, Timothy G; 
charm AT cs.illinois.edu<mailto:charm AT cs.illinois.edu>
Subject: RE: Global variables in Charm++

Thanks Phil. I just added –E to my OPTS parameter, but then all hell breaks 
loose.
This is what charmc says is happening when it tries to compile my .ci file:
../../../bin/charmc -Ofast -DRADIUS=1 -DSTAR -E  jacobi2d.ci
And this is the line in my .ci file that it complains about:
  readonly double weight[(2*RADIUS+1)*(2*RADIUS+1)];

Output:
[rfvander@bar1
 PRKstencil5]$ make
../../../bin/charmc -Ofast -DRADIUS=1 -DSTAR -E  jacobi2d.ci
STDIN:8: Charmxi syntax error> syntax error
Invalid construct
Fatal Error by charmc in directory 
/home/rfvander/charm/examples/charm++/PRKstencil5
   Command ../../../bin/charmxi -orig-file jacobi2d.ci returned error code 1
charmc exiting...
../../../bin/charmc -Ofast -DRADIUS=1 -DSTAR -c jacobi2d.C
jacobi2d.C(1): catastrophic error: cannot open source file "jacobi2d.decl.h"
  #include "jacobi2d.decl.h"

By the way, you may wonder about the subject line of this message. It started 
because I wanted a (small) 2D array as a global variable. I couldn’t get that 
to work (is that by design?), so made it into a 1D array. And then I ran into 
the issue I just reported.

Rob

From:unmobile AT gmail.com<mailto:unmobile AT gmail.com>
 
[mailto:unmobile AT gmail.com]
 On Behalf Of Phil Miller
Sent: Friday, September 26, 2014 3:37 PM
To: Van Der Wijngaart, Rob F
Cc: Nikhil Jain; Kunzman, David M; Hammond, Jeff R; Mattson, Timothy G; 
charm AT cs.illinois.edu<mailto:charm AT cs.illinois.edu>
Subject: Re: Global variables in Charm++

For historical reasons [1], charmc defaults to *not* running the preprocessor 
on .ci files. Preprocessing .ci files can be enabled by passing charmc the -E 
flag when it's working on .ci files.

[1] Enabling pre-processing when it wasn't historically the default risks 
breaking existing application code by having macros that may have been used 
as identifiers in .ci files suddenly be subject to expansion/substitution.

On Fri, Sep 26, 2014 at 5:31 PM, Van Der Wijngaart, Rob F 
<rob.f.van.der.wijngaart AT intel.com<mailto:rob.f.van.der.wijngaart AT intel.com>>
 wrote:

Hello Nikhil,



I have a symbol that I define on the compile line (i.e. I stuff it in OPTS, 
as below):

OPTS=-DRADIUS=1

CHARMC=../../../bin/charmc $(OPTS)

When I now use RADIUS in my .C file, the C preprocessor does its work nicely 
and recognizes that I have defined RADIUS, and also what its value is. 
However, when I use RADIUS in the .ci file, charmc croaks. So is it true that 
no preprocessor is run on .ci files? Thanks!



Rob