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

skywon
Beginner
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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 /

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Gennady_F_Intel
Moderator
343 Views

Did you check the error value ( ierr)?

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skywon
Beginner
343 Views

Sure, ierr = 0 in all cases

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