| Calling fortran [message #7157] |
Thu, 10 October 1996 00:00  |
hto
Messages: 15
Registered: April 1996
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Junior Member |
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Does anyone have an example of calling Fortran from IDL?
Howard Onishi
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| Re: Calling fortran [message #7246 is a reply to message #7157] |
Fri, 11 October 1996 00:00  |
Andy Loughe
Messages: 174
Registered: November 1995
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Senior Member |
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On Thu, 10 Oct 1996, Howard Onishi wrote:
> Does anyone have an example of calling Fortran from IDL?
> Howard Onishi
>
Yep! You will have to chage the link statement to fit your needs.
;=========================================================== ============
; Originator: Andrew F. Loughe
;
; *** SUN SOLARIS 2.3 TEST ***
; Procedure to call a FORTRAN program from within IDL.
; The first 100 primes are computed in the FORTRAN program and
; passed into an IDL vector called prime_nums.
; We pass into the subroutine the number of primes desired.
;
; NOTE: A large number of "nonsense" function calls are made
; from within the FORTRAN subroutine in order to test
; that the link is robust. It found a problem with
; atan2 and datan2.
; **** Set these for yourself ****
DIR = '/home/afl/ensemble/weights/src/idl/'
LIB_DIR = '/usr/lib/'
; This doesn't quite look like a shared object library!!
; May not need all three libraries, but for other tests I did need them.
compile = 1
if (compile eq 1) then begin
SRC = DIR + 'primes.f '
OBJ = DIR + 'primes.o '
OUT = DIR + 'primes.so '
LIB = LIB_DIR + 'libV77.a ' + LIB_DIR + 'libF77.a ' + $
LIB_DIR + 'libsunmath.a '
spawn, 'f77 -c -Kpic ' + SRC
spawn, 'ld -G -o ' + OUT + OBJ + LIB
endif
num_primes = 100L ; Want 100 primes.
prime_nums = lonarr(num_primes) ; Initialize the prime_nums vector.
; Call a FORTRAN program to do the computation.
a = CALL_EXTERNAL(DIR + 'primes.so', 'primes_', num_primes, prime_nums)
print, prime_nums(*)
end
C=========================================================== ===========
C Originator: Andrew F. Loughe
C
C *** SUN SOLARIS 2.3 TEST ***
C A rather simple, inefficient, poorly nested, quickly written,
C subroutine (apology accepted?) to compute the first N primes.
C It is used to demonstrate the ability of IDL to call a FORTRAN
C subroutine to accomplish some task, accepting an input paramter,
C and returning some values.
C num_primes is passed into this subroutine from IDL.
C
C NOTE:
C Some nonsense function calls are added to see if our link is robust.
C From this test I learned that atan2 and datan2 are symbols which
C could not be found.
subroutine primes1(num_primes, prime)
implicit none
integer i, j, icount, num_primes
integer prime(num_primes)
real r, r2
double precision d, d2
prime(1) = 2 ! By definition 1 is not prime.
prime(2) = 3
prime(3) = 5 ! This simple method requires
prime(4) = 7 ! specification of primes under 10.
icount = 4
C Loop through a large number of integers.
C Return only "num_primes" primes.
do 100 i = prime(icount)+2, 1e8, 2
C Test for an even divisor.
do 200 j = 3, int( sqrt( float(i) ) ), 2
if ( mod(i,j) .eq. 0 ) goto 100 ! Number not prime.
200 continue
C A prime has been found!
icount = icount + 1
prime(icount) = i
if (icount .gt. num_primes-1) goto 300 ! Only want num_primes
100 continue
C SOME NONSENSE FUNCTION CALLS:
C Sometimes a particular symbol is not found, so the CALL_EXTERNAL
C routine fails. Let's do some nonsense function calls to see if
C our link is robust. Sorry, not all FORTRAN functions are tested.
300 i = 100
r = 100.
d = 100.
i = iabs(i)
r = abs(r)
d = dabs(d)
i = max0(i, 2)
r = amax1(r, 3.)
d = dmax1(d, d*d)
i = min0(i, 2)
r = amin1(r, 3.)
d = dmin1(d, d*d)
r = sqrt(r)
d = dsqrt(d)
r = exp(r)
d = dexp(d)
r = alog( abs(r) )
d = dlog( dabs(d) )
r = alog10( abs(r) )
d = dlog10( dabs(d) )
r = sin(r)
d = dsin(d)
r = cos(r)
d = dcos(d)
i = 100
r = 100.
d = 100.
r2= .5
d2= .5
r = tan(r)
d = dtan(d)
r = asin(r)
d = dasin(d)
r = acos(r)
d = dacos(d)
r = atan(r)
d = datan(d)
C COULD NOT FIND THESE 2 SYMBOLS
C r = atan2(r, r2)
C d = datan2(d, d2)
r = sinh(r)
d = dsinh(d)
r = cosh(r)
d = dcosh(d)
r = tanh(r)
d = dtanh(d)
return
end
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| Re: Calling fortran [message #7250 is a reply to message #7157] |
Thu, 10 October 1996 00:00 |
dors
Messages: 8
Registered: June 1994
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Junior Member |
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Examples of how to use call_external come WITH idl. The are located
in a path something like: /usr/local/rsi/idl_4/external/examples/sharelib/
Also check out the IDL FORTRAN-FAQ:
ftp://eos.crseo.ucsb.edu:/pub/idl/idl-fortran.Z
Note that the call external example given uses a C interface program,
it is also possible to use a FORTRAN interface program.
A very simple shell of a FORTRAN interface program would look like:
(check out the post I made last week about this with a more
complicated example, I erased it, maybe someone else will be kind
enough to repost it. :)
c Interface routine
SUBROUTINE pass (argc, argv)
c note size of intergers on the next line depends on your system pointer size
INTEGER*8 argc, argv(*)
CALL mysub (%VAL(argv(1)),%val(argv(2)))
RETURN
END
SUBROUTINE mysub (a, b)
integer*4 a, b
print *, a, b
end
idl:
j=CALL_EXTERNAL ('mylib.so','pass_',NBLOCKS,len,VALUE=[0,0])
Eric
--
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| Eric E. Dors \| Internet: eric.dors@unh.edu |
| 203 Van Allen Hall | |
| Iowa City, IA 52242 | |
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| "if free particles were truly free..." |
| "they wouldn't be represented by bras, <k| " |
| ---oh no, how did a physics joke make it in here? :^) |
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