Hi all, I'm cross posting this to the NumPy List and the MacPython list, because it involves NumPy on the Mac, so I'm not sure which group can be most helpfull. It took me a while to get this far, and I finally got everything to compile, but now I have a crashing problem. It seems to be a problem with PyArray_Type not being seen as a PyObject. I am pretty new to C, but I have consulted with a number of folks I work with that know a lot more than I do, and this seems to be a pretty esoteric C issue. It also seems to be compiler dependent, because I have all this working fine on Linux with gcc. I have chopped my problem down into a very small function that demonstrates the problem. The function takes a contiguous NumPy array of Floats (doubles) and multiplies every element by two (in place), and returns None. Here is the code as it works on Linux: #include "Python.h" #include "arrayobject.h" /* A function that doubles an array of Floats in place*/ static PyObject * minimal_doublearray(PyObject *self, PyObject *args) { PyArrayObject *array; int i, num_elements; double *data_array ; if (!PyArg_ParseTuple(args, "O!", &PyArray_Type, &array)) return NULL; if (array->descr->type_num != PyArray_DOUBLE) { PyErr_SetString(PyExc_ValueError, "array must be of type Float"); return NULL; } data_array = (double *) array->data; /*num_elements = PyArray_Size((PyObject *) array);*/ num_elements = PyArray_Size(array); printf("The size of the array is: %i elements\n",num_elements); for (i= 0; i < num_elements; i++) data_array[i] = 2 * data_array[i]; return Py_None; } static PyMethodDef minimalMethods[] = { {"doublearray", minimal_doublearray, METH_VARARGS}, {NULL, NULL} /* Sentinel */ }; void initminimal() { (void) Py_InitModule("minimal", minimalMethods); } Note that the call to: "PyArray_Size(array)" gives me a "./minimal.c:28: warning: passing arg 1 from incompatible pointer type " on gcc on linux. In CodeWarrior on the Mac, it is an fatal error. With the typcast (see previous commented out line) it gives no warnings, and compiles on both systems. Here is a small script to test it: #!/usr/bin/env python from Numeric import * import minimal print "\nTesting doublearray" a = arange(10.0) print a minimal.doublearray(a) print a print "the second version should be doubled" This works fine on Linux, and gives the appropriate errors if the wrong type object is passed in. On the Mac, it crashes. Trying various things, I found that it crashes on the if (!PyArg_ParseTuple(args, "O!", &PyArray_Type, &array)) return NULL; line. If I use: if (!PyArg_ParseTuple(args, "O", &array)) return NULL; It works. Then it crashes on the: num_elements = PyArray_Size((PyObject *) array); line. If I use another way to determine the number of elements, like: num_elements = 1; for (i=0,i<array->nd,i++) num_elements = num_elements * array->dimensions[1]; Then I can get it to work. What is going on? anyone have any suggestions? MacPython 1.5.2c The NumPy that came with MacPython 1.5.2c CodeWarrior pro 5. Thanks for any suggestions, -Chris -- Christopher Barker, Ph.D. cbarker@jps.net --- --- --- http://www.jps.net/cbarker -----@@ -----@@ -----@@ ------@@@ ------@@@ ------@@@ Water Resources Engineering ------ @ ------ @ ------ @ Coastal and Fluvial Hydrodynamics ------- --------- -------- ------------------------------------------------------------------------ ------------------------------------------------------------------------