C programming

ismba98

How do I create modules written in c inside pythonista

omz

This isn't possible.

dgelessus

There is the ctypes module though, so if you want to call C functions, then you can do that with ctypes. You can even call functions from Python's C API, if you really want to, but that isn't very useful in many cases.

Matteo

@ismba98 Hi, actually it would be possible to run on the fly some C or Fortran codes using a remote python server (SageMathCell for example, it is free and works well). Some info here.

For C codes you can read something here and here.

For Fortran codes something here.

Obviously you must be online with your Pythonista.

As example of C code that you can edit in Pythonista and run using Pythonista and the remote server is the following:

## C file:
C_code = """
int fibonacci(int i)
{
  if (i < 0) return -1; /* F(i) is not defined for negative integers! */
  if (i == 0) return 0;
  else if (i == 1) return 1;
  else return fibonacci(i-1) + fibonacci(i-2);
}
"""

## Spyx file:
Spyx_code = """
cdef extern from "fibonacci.c":
    int fibonacci(int n)
"""

## Create the c file:
with open("fibonacci.c", 'w') as f:
    f.write(C_code)

## Create the spyx file: 
with open("fibonacci.spyx", 'w') as f:
    f.write(Spyx_code)

load("fibonacci.spyx")
num = 10
print(fibonacci(num))



## Fortran77 file:
FORTRAN_code = """
      SUBROUTINE FIB(A,N)
C
C     CALCULATE FIRST N FIBONACCI NUMBERS
C
      INTEGER N
      REAL*8 A(N)
      DO I=1,N
         IF (I.EQ.1) THEN
            A(I) = 1.0D0
         ELSEIF (I.EQ.2) THEN
            A(I) = 1.0D0
         ELSE
            A(I) = A(I-1) + A(I-2)
         ENDIF
      ENDDO
      END
"""

fortran(FORTRAN_code, globals())
import numpy as np
num = 10
a = np.array(xrange(1,num+1), dtype=float)
fib(a, num)
print(a)

There is no reason to code in C or Fortran using Pythonista, but sometimes user wants to test some existing open source codes in these programming
languages.

Regards.
Matteo

augusto

@Matteo excuse my ignorance and my English, how do I install the sage package and where do I take the fortran function?
I have an iPhone. Thanks

Matteo

@augusto Hi, you don't need to install SageMath in Pythonista, it is impossible. You can use a set of python scripts, that run well in Pythonista, in order to send to the remote server some C or Fortran codes/pieces of code to test them.

In short: with Pythonista you can do a lot of things (trust me, a lot), and a thing that you can do easly with Pythonista is to send some code to a remote python server (SageMathCell, please give credits to Andrey, the main maintainer, for this free service), wait for response and process the output, in order to use it in Pythonista, like a global variable that you can use as you want. You must be online to use the service.

Please follow the instructions in the corresponding thread here. Try by yourself, you must download the last version of sage_interface, extract it in any folder of Pythonista, see what is inside that folder to understand how to send some Fortran code and obtain the output as a printed string or number/array.
If you need more info, please ask in that thread.

Thanks
Regards

augusto

Thank you @Matteo for your comments. What I did not understand was that their examples run on the sage side and not on the iOS device. Thanks a lot.

Matteo

@augusto Yes, fortran codes run only by sage point of view, but you can use Pythonista to write fortran codes, test and use them when online, without using other ios apps that most likely are only able to send fortran code. Bye