EpetraExt
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src
btf
pothen
main.f
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c
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c
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c Purpose: Fortran driver of genbtf, generate block triangular
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c form. A structurally nonsingular matrix is permuted
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c
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c (A(rowperm(i), (colperm(j)), 1 <= i,j, <=n)
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c
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c to block upper triangular with sqcmpn blocks.
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c If matsng != 0, then the matrix is structurally singular
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c (for example has a zero row), and has a complex
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c block triangular form.
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c
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c
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c rcmstr ccmstr
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c
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c If matsng != 0, then the matrix is structurally singular
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c (for example has a zero row), and has a complex
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c block triangular form.
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c
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c
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c test input
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parameter(n=3, nnz= 3)
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c and C-style indexing.
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c
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c
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c
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c
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c
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c Start with an n by n matrix in sparse row format
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c ja, ia: column indices and row pointers
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c
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c integer input scalars
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c integer msglvl = 0, output = 6
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integer
msglvl, output
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c
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c integer input arrays
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integer
ia(n+1) , ja(nnz), iat(n+1), jat(nnz)
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c
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c local work space
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integer
w(10*n), i, j
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c
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c integer output scalars
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c
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integer
matsng
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c horizontal block: rows, columns, connected components
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integer
nhrows, nhcols, hrzcmp
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c square block: rows=columns, connected components
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integer
nsrows, sqcmpn
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c vertical block: rows, columns, connected components
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integer
nvrows, nvcols, vrtcmp
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c
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c integer output arrays
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c rowperm: row permutation,
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c cotn: column permutation, old to new
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integer
colperm(n), rowperm(n), rcmstr(n+1), ccmstr(n+1)
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matsng = 0
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msglvl = 0
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output = 6
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c
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c More test input
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ia(1) = 0
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ia(2) = 1
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ia(3) = 2
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ia(4) = 3
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c
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ja(1) = 1
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ja(2) = 2
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ja(3) = 0
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c
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c
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c Convert from C indexing to Fortran
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c if( nnz != ia(n+1) )then
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c stop I can not remember Fortran syntax.
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c endif
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do
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ia(i) = ia(i) + 1
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continue
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do
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ja(i) = ja(i) + 1
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continue
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call
mattrans
(n,n,ja,ia,jat,iat)
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c
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c
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print*,
'Input (row, column)'
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do
200 i=1,n
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do
201 j= ia(i),ia(i+1)-1
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print*,
' '
,i,ja(j)
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continue
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200
continue
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c
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c
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call
genbtf
( n, n,
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$ iat , jat, ia, ja, w ,
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$ rowperm , colperm , nhrows,
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$ nhcols, hrzcmp, nsrows, sqcmpn, nvrows,
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$ nvcols, vrtcmp, rcmstr, ccmstr, msglvl, output )
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c
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c
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if
( nhrows .gt. 0)
then
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print*,
"horizontal block:"
, nhrows, nhcols, hrzcmp
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endif
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print*, sqcmpn,
" blocks"
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if
( nvrows .gt. 0)
then
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print*,
"vertical block:"
, nvrows, nvcols, vrtcmp
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endif
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matsng = nhrows + nvrows + hrzcmp + vrtcmp
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if
( matsng .eq. 0)
then
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do
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print*,
' '
, rcmstr(hrzcmp+i), ccmstr(hrzcmp+i)
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401
continue
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else
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print*,
'Structurally singular matrix'
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endif
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c
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print*,
'Permuted (row, column)'
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do
300 i=1,n
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k = rowperm(i)
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do
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print*,
' '
, i,ja(colperm(j))
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continue
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continue
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c
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c rowperm --, colperm --
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c rcmstr --, ccmstr --
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c
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c
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end
mattrans
subroutine mattrans(m, n, ja, ia, jao, iao)
Definition:
mattrans.f:2
genbtf
subroutine genbtf(nrows, ncols, colstr, rowidx, rowstr, colidx, w, rnto, cnto, nhrows, nhcols, hrzcmp, nsrows, sqcmpn, nvrows, nvcols, vrtcmp, rcmstr, ccmstr, msglvl, output)
Definition:
genbtf.f:6
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1.8.16
