Intel® oneAPI Math Kernel Library
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dcsrilut produces results that are not ascending order at the last row.

skywon
Beginner
149 Views

I'm trying to use dcsrilut but it produces output vectors that are not sorted by ascending order.

Should I sort them before use them in another csr formatted matrix-vector routines.

Here is a sample program and you can see 'lu' and 'jlu' are not ordered in ascending at 5-th row in output.

Please check it and let me know the reason why it does or how to use it properly.

Thanks in advance,

skywon.

program dcsrilut_error
implicit none

real *8 a(16), lu(18), dpar(128), tol
integer ia(6), ja(16), ilu(6), jlu(18), n, i, j, k, ipar(128), mfil, ierr

data a / 1.0, 1.0, 4.0, &
2.0, 4.0, 1.0, &
2.0, 1.0, 8.0, 2.0, &
4.0, 1.0, &
3.0, 6.0, 2.0, 1.0/
data ja / 1, 2, 5, &
2, 3, 5, &
1, 2, 3, 4, &
3, 4, &
1, 2, 3, 5/
data ia / 1, 4, 7, 11, 13, 17/

n = 5

ipar(31) = 1
dpar(31) = 1.d-5
tol = 1.d-5

do mfil = 1, 3

call dcsrilut(n, a, ia, ja, lu, ilu, jlu, tol, mfil, ipar, dpar, ierr)

write(*, "(/'mfil = ', i2)") mfil
do i = 1, n
do j = ilu(i), ilu(i+1)-1
write(*, "(i2$)") jlu(j)
end do
write(*,"(' /'$)")
end do
write(*, *)

end do
end program

output of the above program is as follows:


mfil = 1
1 5 / 2 3 / 1 3 5 / 3 4 5 / 1 5 /

mfil = 2
1 2 5 / 2 3 5 / 1 2 3 4 5 / 3 4 5 / 4 1 5 /

mfil = 3
1 2 5 / 2 3 5 / 1 2 3 4 5 / 3 4 5 / 2 4 1 5 /

0 Kudos
2 Replies
Gennady_F_Intel
Moderator
149 Views

Did you check the error value ( ierr)?

skywon
Beginner
149 Views

Sure, ierr = 0 in all cases

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