Re: How to call Fortran functions from LuaJIT
- From: Ciprian Tomoiaga <ciprian.tomoiaga@xxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Fri, 28 Nov 2014 00:00:47 +0100
Hi Pedro,
Yes, it is possible without having to go through C. First, you have to
compile the fortran. I use gfortran:
gfortran -O3 -shared -fPIC your_file.f -o libyour_file.so
The flags -shared and -fPIC are important to make it loadable.
Then, in LuaJIT you define the functions as you would do in C, like the
article you pointed describes.
Example:
if in Fortran you have:
----------------------------------------
subroutine init(p1,p2,p3)
implicit none
integer p1,p2
double precision p3
........
----------------------------------------
Then in LuaJIT you would have:
--------------------------------------------
local ffi = require'ffi'
local mylib = ffi.load("path/to/libmy_file.so")
ffi.cdef [[
void init_(int *p1, int *p2, double *p3);
]]
-- You need pointers to the raw types, which in this case can be
represented as an array of size 1
local p1, p2, p3 = ffi.new("int[1]"), ffi.new("int[1]"),
ffi.new("double[1]")
-- say p1, p2 are input params and p3 output; set p1, p2 to desired values
p1[0] = 2
p2[0] = 3
-- call your function
mylib.init(p1, p2, p3)
-- now you have the result in p3, which is a 'pointer'
if p3[0] ~= 0 then
-- ...
This is how we've been using it. If anyone has suggestions, please, they
are more than welcome.
P.S. You should declare your 'pointer' types once, and use them as
constructors:
local int_p = ffi.typeof("int[1]")
local p1 = int_p()
Best regards,
Ciprian
--
Ciprian *Tom*oiaga
On 27 November 2014 at 17:58, Pedro Tabacof <tabacof@xxxxxxxxx> wrote:
> Hello,
>
> I'd like to know how to use the FFI to call a function from a Fortran 77
> code. One way I see is to translate the code to C using f2c, but this is
> far from ideal.
>
> Calling Fortran from C code is simple, but you need to compile the o bject
> file using a Fortran compiler such as gfortran (see
> http://www.xgear.eu/callfortranfromc.html).
>
> Is there an easy way to do this from LuaJIT?
>
> Thank you,
> Pedro.
>
> --
> Pedro Tabacof
>
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