I have written a simple C++ program in my efforts to learn how to
extend Python. It is shown below. Everything compiles and installs
correctly, but I get strange answers. I know the function "Pi" is
correct because when I call it from a C++ code it gives the correct
answers. This is what I get when I run it in Python:
Python 2.3 (#1, Sep 13 2003, 00:49:11)
[GCC 3.3 20030304 (Apple Computer, Inc. build 1495)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import Pie
>>> Pie.Pi(100)
4.244022824665725e-314
>>> Pie.Pi(100000)
6.3659915186006512e-314
>>> Pie.Pi(1000000)
6.3659881268399925e-314
Thanks for the help,
Jeremy
1 /* PiPython.cpp*/
2 #include<Python.h>
3
4 using namespace std;
5
6 double Pi(int Particles)
7 {
8 double PiEst = 0.0;
9 double x,y;
10 int CircleArea = 0;
11 for ( int i = 0; i <= Particles; i++)
12 {
13 x = (double) rand()/RAND_MAX;
14 y = (double) rand()/RAND_MAX;
15
16 if (sqrt(pow(x,2)+pow(y,2)) <= 1.0)
17 {
18 CircleArea++;
19 }
20 }
21 return 4.0*(double(CircleArea)/double(Particles));
22 }
23
24
25 PyObject *wrap_Pi(PyObject *self, PyObject *args)
26 {
27 int Particles;
28 int Pie;
29 if (!PyArg_ParseTuple(args, "i", &Particles))
30 return NULL;
31 Pie = Pi(Particles);
32 return Py_BuildValue("d", Pie);
33 }
34
35 /* List of all functions in the module */
36 static PyMethodDef PieMethods[] =
37 {
38 {"Pi", wrap_Pi, METH_VARARGS},
39 {NULL, NULL}
40 };
41
42 /* Module Initialization function */
43 PyMODINIT_FUNC initPie(void)
44 {
45 Py_InitModule("Pie", PieMethods);
46 }
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