Not only Cfloat, but also Float32 worked, like Cfloat[1.2] OR Float32[1.1].
On Thursday, August 6, 2015 at 9:13:58 AM UTC-4, Byung Lee wrote:
>
> Hi,
>
> I got an answer. You need to use Cfloat for REAL instead of Cdouble for
> DOUBLE PRECISION.
>
>
>
> On Wednesday, August 5, 2015 at 6:01:05 PM UTC-4, Byung Lee wrote:
>>
>> Hi,
>>
>> When I tried the following Fortran routine (abc.f), it worked using the
>> following shared file and ccall.
>> But when I tried after changing DOUBLE PRECISION with REAL, it did not
>> work. How should it be fixed.
>>
>> This is what I saw on the Internet and worked:
>>
>> abc.f file I saw on the Internet
>>
>> SUBROUTINE MULTIPLY(A,B,C)
>> DOUBLE PRECISION A,B,C
>> C = A*B
>> RETURN
>> END
>>
>> gfortran abc.f -o abc.so -shared -fPIC
>>
>> a = 2.0
>> b = 4.2
>> n = Float64[1.0]
>>
>> ccall((:multiply_, "abc.so"), Void,
>> (Ptr{Float64},Ptr{Float64},Ptr{Float64}),&a,&b, n)
>>
>> julia> n
>> 1-element Array{Float64,1}:
>> 8.4
>>
>> Again ccall worked with DOUBLE PRECISION.
>>
>> When I used REAL like the following:
>> SUBROUTINE MULTIPLY(A,B,C)
>> DOUBLE PRECISION A,B,C
>> C = A*B
>> RETURN
>> END
>>
>> and used the same procedure like
>>
>> gfortran abc.f -o abc.so -shared -fPIC
>>
>> a = 2.0
>> b = 4.2
>> julia> n = Array(Float64)
>> 0-dimensional Array{Float64,0}:
>> 0.0
>>
>> julia> ccall((:multiply_, "/fullPathTo/abc.so"), Void,
>> (Ptr{Float64},Ptr{Float64},Ptr{Float64}), &a, &b, n)
>>
>> julia> n
>> 0-dimensional Array{Float64,0}:
>> 1.061e-314
>>
>> The default value of 0.0 changed to 1.061e-314, which is not the correct
>> answer.
>>
>> When I assigned a specific number to n:
>> julia> n = Float64[1.0]
>> 1-element Array{Float64,1}:
>> 1.0
>>
>> julia> ccall((:multiply_, "/fullPathTo/abc.so"), Void,
>> (Ptr{Float64},Ptr{Float64},Ptr{Float64}), &a, &b, n)
>>
>> Then the array element value was not changed.
>> julia> n
>> 1-element Array{Float64,1}:
>> 1.0
>>
>> I am wondering why it does not work with REAL variables.
>> I tried Logical, Int, and Character variables, along with Double
>> Precision.
>> All worked, except for REAL.
>>
>> Thanks,
>>
>> Byung Lee
>>
>>
>>
>>
>> On Friday, November 14, 2014 at 4:08:50 PM UTC-5, Andre Bieler wrote:
>>>
>>> tried calling a simple fortran function from julia but did not succeed:
>>> this is the fortran code:
>>>
>>> !fileName = simplemodule.f95
>>> module simpleModule
>>>
>>> contains
>>> function foo(x)
>>> integer :: foo, x
>>> foo = x * 2
>>> end function foo
>>>
>>>
>>> end module simplemodule
>>>
>>>
>>> which is then compiled with:
>>>
>>> *gfortran simplemodule.f95 -o simplemodule.so -shared -fPIC*
>>>
>>> and finally the julia call is:
>>>
>>>
>>> ccall((:foo, "/fullPathTo/simpleMod.so"), Int32, (Int32,), 3)
>>>
>>>
>>> which then leads to the following error:
>>>
>>> ERROR: ccall: could not find function foo in library
>>> /fullPathTo/simpleMod.so
>>> in anonymous at no file
>>>
>>>
>>>
>>> when compiling with:
>>>
>>> gfortran -c simplemodule.f95 -o simplemodule.so -shared -fPIC
>>>
>>> i get a different error:
>>>
>>> *ERROR: error compiling anonymous: could not load module
>>> /fullPathTo/simplemodule.so: /fullPathTo/simplemodule.so:*
>>> *only ET_DYN and ET_EXEC can be loaded*
>>>
>>>
>>>
>>> Can anyone tell me what I am missing?
>>> I do realize I would not need to call fortran to multiply a variable by
>>> 2, but its a starting point..
>>>
>>>
>>> Thanks!
>>> Andre
>>>
>>
