Merged internal comments for FND_OWNER methods.

base/internals/psb_indx_map_fnd_owner.F90

@@ -30,21 +30,28 @@
 !   
 !   
 !
-! File: psi_fnd_owner.f90
+! File: psb_fnd_owner.f90
 !
-! Subroutine: psi_fnd_owner
+! Subroutine: psb_fnd_owner
 !   Figure out who owns  global indices. 
 ! 
 ! Arguments: 
-!    nv       - integer                 Number of indices required on  the calling
-!                                       process 
 !    idx(:)   - integer                 Required indices on the calling process.
 !                                       Note: the indices should be unique!
 !    iprc(:)  - integer(psb_ipk_), allocatable    Output: process identifiers for the corresponding
 !                                       indices
-!    desc_a   - type(psb_desc_type).    The communication descriptor.        
+!    idxmap   - class(psb_indx_map).    The index map
 !    info     - integer.                return code.
 !
+!  This is the default implementation of the FND_OWNER method.
+!  If a particular index map class has additional information, it can override it
+!  (see e.g. the GEN_BLOCK_MAP class).
+!
+!  1. Check if IDXM%PARTS is available, and use it; or
+!  2. Check if TEMPVG(:) is allocated, and use it; or
+!  3. Call the general method PSI_GRAPH_FND_OWNER. 
+! 
+! 
 subroutine psb_indx_map_fnd_owner(idx,iprc,idxmap,info)
   use psb_serial_mod
   use psb_const_mod

base/internals/psi_a2a_fnd_owner.F90

@@ -29,22 +29,24 @@
 !    POSSIBILITY OF SUCH DAMAGE.
 !   
 !
+! File: psi_a2a_fnd_owner.f90
 !
-! File: psi_fnd_owner.f90
-!
-! Subroutine: psi_fnd_owner
+! Subroutine: psi_a2a_fnd_owner
 !   Figure out who owns  global indices. 
 ! 
 ! Arguments: 
-!    nv       - integer                 Number of indices required on  the calling
-!                                       process 
 !    idx(:)   - integer                 Required indices on the calling process.
 !                                       Note: the indices should be unique!
 !    iprc(:)  - integer(psb_ipk_), allocatable    Output: process identifiers for the corresponding
 !                                       indices
-!    desc_a   - type(psb_desc_type).    The communication descriptor.        
+!    idxmap   - class(psb_indx_map).    The index map
 !    info     - integer.                return code.
 !
+! This version does not assume any prior knowledge about the process topology,
+! so it goes for an all-to-all by building an auxiliary neighbours list and
+! reusing the neighbour version.
+! 
+! 
 subroutine psi_a2a_fnd_owner(idx,iprc,idxmap,info)
   use psb_serial_mod
   use psb_const_mod

base/internals/psi_adjcncy_fnd_owner.F90

@@ -30,12 +30,28 @@
 !   
 !   
 !   
-! File: psi_fnd_owner.f90
 !
-! Subroutine: psi_fnd_owner
+! File: psi_adjcncy_fnd_owner.f90
+!
+! Subroutine: psi_adjcncy_fnd_owner
 !   Figure out who owns  global indices. 
 ! 
 ! Arguments: 
+!    idx(:)   - integer                 Required indices on the calling process.
+!                                       Note: the indices should be unique!
+!    iprc(:)  - integer(psb_ipk_), allocatable    Output: process identifiers for the corresponding
+!                                       indices
+!    adj(:)   - integer(psb_ipk_)       Input: list of topological neighbours for current process.
+!
+!    idxmap   - class(psb_indx_map).    The index map
+!    info     - integer.                return code.
+!
+! This version takes on input a list of processes that are assumed to 
+! be topological neighbours of the current one. Each process will send to all 
+! of its neighbours the list of indices for which it is trying to find the
+! owner, prepare its own answers, and collect answers from others.
+! There are three possibile implementations: using mpi_alltoallv, using mpi_isend/irecv,
+! using psb_snd/psb_rcv. The default is mpi_alltoallv.
 ! 
 subroutine psi_adjcncy_fnd_owner(idx,iprc,adj,idxmap,info)
   use psb_serial_mod
@@ -69,8 +85,10 @@ subroutine psi_adjcncy_fnd_owner(idx,iprc,adj,idxmap,info)
        & last_ih, last_j, nidx, nrecv, nadj
   integer(psb_ipk_) :: mglob, ih
   integer(psb_ipk_) :: ictxt,np,me
-  logical, parameter  :: gettime=.false., new_impl=.true.
-  logical, parameter  :: a2av_impl=.true., debug=.false.
+  logical, parameter  :: gettime=.false., debug=.false.
+  logical, parameter  :: a2av_impl=.true.
+  logical, parameter  :: mpi_irecv_impl=.false.
+  logical, parameter  :: psb_rcv_impl=.false.
   real(psb_dpk_)      :: t0, t1, t2, t3, t4, tamx, tidx
   character(len=20)   :: name
 
@@ -175,6 +193,10 @@ subroutine psi_adjcncy_fnd_owner(idx,iprc,adj,idxmap,info)
     call mpi_alltoallv(tproc,rvsz,rvidx,psb_mpi_ipk_integer,&
          & lclidx,sdsz,sdidx,psb_mpi_ipk_integer,icomm,iret)
 
+    !
+    ! Because IPRC has been initialized to -1, the MAX operation selects
+    ! the answers. 
+    !
     do i=0, np-1
       if (sdsz(i)>0) then
         ! Must be nidx == sdsz(i) 
@@ -183,8 +205,7 @@ subroutine psi_adjcncy_fnd_owner(idx,iprc,adj,idxmap,info)
     end do
 
     if (debug) write(0,*) me,' End of adjcncy_fnd ',iprc(1:nidx)    
-  else
-    if (new_impl) then
+  else if (mpi_irecv_impl) then
     !
     ! First simple minded version with auxiliary arrays
     ! dimensioned on NP.
@@ -303,7 +324,7 @@ subroutine psi_adjcncy_fnd_owner(idx,iprc,adj,idxmap,info)
     end do
     if (debug) write(0,*) me,' End of adjcncy_fnd ',iprc(1:nidx)
 
-    else
+  else if (psb_rcv_impl) then 
 
     Allocate(hidx(0:np),hsz(np),&
          & sdsz(0:np-1),rvsz(0:np-1),stat=info)
@@ -371,7 +392,10 @@ subroutine psi_adjcncy_fnd_owner(idx,iprc,adj,idxmap,info)
       if (nidx > 0) call psb_rcv(ictxt,tproc(1:nidx),adj(j))
       iprc(1:nidx) = max(iprc(1:nidx), tproc(1:nidx))
     end do
-    end if
+  else
+    info = psb_err_internal_error_
+    call psb_errpush(info,name,a_err='invalid exchange alg choice')
+    goto 9999      
   end if
 
   call psb_erractionrestore(err_act)