/*
This source code file is part of thread_mpi.  
Written by Sander Pronk, Erik Lindahl, and possibly others. 

Copyright (c) 2009, Sander Pronk, Erik Lindahl.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1) Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2) Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3) Neither the name of the copyright holders nor the
   names of its contributors may be used to endorse or promote products
   derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY US ''AS IS'' AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL WE BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

If you want to redistribute modifications, please consider that
scientific software is very special. Version control is crucial -
bugs must be traceable. We will be happy to consider code for
inclusion in the official distribution, but derived work should not
be called official thread_mpi. Details are found in the README & COPYING
files.
*/


#ifdef THREAD_MPI_OPS

/* cpp wizardry follows... 

This file is #included directly from thread_mpi.c, and constructs 
MPI_Reduce operators. 

What this does is create the min, max, sum, prod, etc. functions for a given
datatype (pre-defined as TYPE, with identifier name TYPENM) and puts pointers 
to these functions in an array called oplist_TYPENM. 

gmx_thread_mpi_reduce.c includes this file once for each type used by MPI, 
and thus builds up a set of arrays of function pointers, that then get used
in the mpi_datatype_ structure. This way, each operation/datatype entry
that makes sense can be extracted easily. Note that we don't (yet) support
user-defined ops */

#define FNAMEr(tp,fn) tMPI_##tp##_##fn
#define FNAME(tp,fn) FNAMEr(tp,fn)

/* macros to define functions and prototypes based on a name and an operation */
#define FNr(tp,fname,fn) \
static void tMPI_##tp##_##fname  (void *dest, void *src_a, void *src_b, \
                                  int count) \
{ \
    /*printf("in function %s, count=%d\n", __FUNCTION__, count);*/\
    TYPE *a=(TYPE*)src_a; \
    TYPE *b=(TYPE*)src_b; \
    TYPE *d=(TYPE*)dest; \
    int i; \
    for(i=0;i<count;i++) \
        d[i]=(TYPE)(fn(a[i],b[i])); \
}  

#define FN(tp,fname,fn) FNr(tp,fname,fn)

#define OPFNr(tp,fname,operator)  \
static void tMPI_##tp##_##fname  (void *dest, void *src_a, void *src_b, \
                                  int count) \
{ \
    /*printf("in function %s, count=%d\n", __FUNCTION__, count);*/\
    TYPE *a=(TYPE*)src_a; \
    TYPE *b=(TYPE*)src_b; \
    TYPE *d=(TYPE*)dest; \
    int i; \
    for(i=0;i<count;i++) \
        d[i]=(TYPE)(a[i] operator b[i]); \
}  

#define OPFN(tp,fname,operator) OPFNr(tp,fname,operator)


/* these are the function prototypes + definitions: */
#define MAX(a, b)  (( (a) > (b) ) ? (a) : (b))
FN(TYPENM,max,MAX)
#undef MAX
#define MIN(a, b)  (( (a) < (b) ) ? (a) : (b))
FN(TYPENM,min,MIN)
#undef MIN
OPFN(TYPENM,sum,+)
OPFN(TYPENM,prod,*)
#if INTTYPE!=0
OPFN(TYPENM,land,&&)
OPFN(TYPENM,band,&)
OPFN(TYPENM,lor,||)
OPFN(TYPENM,bor,|)
OPFN(TYPENM,bxor,^)
#define XOR(a, b)  ( (!a) ^ (!b) ) 
FN(TYPENM,lxor,XOR)
#undef XOR
#endif

#define OPARRAYr(tp) oplist_##tp
#define OPARRAY(tp) OPARRAYr(tp)

tMPI_Op_fn OPARRAY(TYPENM)[] = {
    FNAME(TYPENM,max),
    FNAME(TYPENM,min),
    FNAME(TYPENM,sum),
    FNAME(TYPENM,prod),
#if INTTYPE
    FNAME(TYPENM,land),
    FNAME(TYPENM,band),
    FNAME(TYPENM,lor),
    FNAME(TYPENM,bor),
    FNAME(TYPENM,lxor),
    FNAME(TYPENM,bxor)
#else
    0,
    0,
    0,
    0,
    0,
    0
#endif
};


#undef FNAME
#undef FNAMEr
#undef OPARRAYr
#undef OPARRAY
#undef FN
#undef FNr
#undef OPFN
#undef OPFNr

#undef TYPE
#undef TYPENM
#undef INTTYPE

#endif
