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psblas3/base/serial/f77/symbmm.f

120 lines
3.0 KiB
Fortran

c == =====================================================================
c Sparse Matrix Multiplication Package
c
c Randolph E. Bank and Craig C. Douglas
c
c na.bank@na-net.ornl.gov and na.cdouglas@na-net.ornl.gov
c
c Compile this with the following command (or a similar one):
c
c f77 -c -O smmp.f
c
c == =====================================================================
subroutine symbmm
* (n, m, l,
* ia, ja, diaga,
* ib, jb, diagb,
* ic, jc, diagc,
* index)
use psb_const_mod
use psb_realloc_mod
use psb_sort_mod, only: psb_msort
c
integer(psb_ipk_) :: ia(*), ja(*), diaga,
* ib(*), jb(*), diagb, diagc, index(*)
integer(psb_ipk_), allocatable :: ic(:),jc(:)
integer(psb_ipk_) :: nze, info
c
c symbolic matrix multiply c=a*b
c
if (size(ic) < n+1) then
write(psb_err_unit,*)
+ 'Called realloc in SYMBMM '
call psb_realloc(n+1,ic,info)
if (info /= psb_success_) then
write(psb_err_unit,*)
+ 'realloc failed in SYMBMM ',info
end if
endif
maxlmn = max(l,m,n)
do 10 i=1,maxlmn
index(i)=0
10 continue
if (diagc.eq.0) then
ic(1)=1
else
ic(1)=n+2
endif
minlm = min(l,m)
minmn = min(m,n)
c
c main loop
c
do 50 i=1,n
istart=-1
length=0
c
c merge row lists
c
do 30 jj=ia(i),ia(i+1)
c a = d + ...
if (jj.eq.ia(i+1)) then
if (diaga.eq.0 .or. i.gt.minmn) goto 30
j = i
else
j=ja(jj)
endif
c b = d + ...
if (index(j).eq.0 .and. diagb.eq.1 .and. j.le.minlm)then
index(j)=istart
istart=j
length=length+1
endif
if ((j<1).or.(j>m)) then
write(psb_err_unit,*)
+ ' SymbMM: Problem with A ',i,jj,j,m
endif
do 20 k=ib(j),ib(j+1)-1
if ((jb(k)<1).or.(jb(k)>maxlmn)) then
write(psb_err_unit,*)
+ 'Problem in SYMBMM 1:',j,k,jb(k),maxlmn
else
if(index(jb(k)).eq.0) then
index(jb(k))=istart
istart=jb(k)
length=length+1
endif
endif
20 continue
30 continue
c
c row i of jc
c
if (diagc.eq.1 .and. index(i).ne.0) length = length - 1
ic(i+1)=ic(i)+length
if (ic(i+1) > size(jc)) then
if (n > (2*i)) then
nze = max(ic(i+1), ic(i)*((n+i-1)/i))
else
nze = max(ic(i+1), nint((dble(ic(i))*(dble(n)/i))) )
endif
call psb_realloc(nze,jc,info)
end if
do 40 j= ic(i),ic(i+1)-1
if (diagc.eq.1 .and. istart.eq.i) then
istart = index(istart)
index(i) = 0
endif
jc(j)=istart
istart=index(istart)
index(jc(j))=0
40 continue
call psb_msort(jc(ic(i):ic(i)+length -1))
index(i) = 0
50 continue
return
end