On Tue, Feb 24, 2004 at 10:10:51PM +0100, Andrea Riciputi wrote:
Hi, I'm running a simulation program partly written in C partly in Python and I use Numeric arrays extensively. At the end of a single run I have a bunch of Numeric arrays containing partial results that I don't need anymore. These arrays have been created on the C side of my code and then copied (actually linked via PyArray_FromDimsAndData) to Numeric arrays. How can I release these arrays and get back memory in order to be able to start the next run?
Simple answer: don't use PyArray_FromDimsAndData. Allocate your array with Python using PyArray_FromDims, and use the data element for your C array, instead of allocating using C and convincing Python to use that. However, there are instances where you can't do that (the memory was allocated by some library, for instance, that needs a custom deallocator, or is from another array type). Then I'd suggest 1) copying the data (depends on how much there is) 2) if the array memory was originally allocated using malloc, you set the OWNDATA flag so Python will free it (going from memory here on the name; check the source). Note that you should be really sure you and Python are using the same allocator/deallocator routines. 3) or using the following trick, best described with some code: MyOtherArrayType *A = a_library_routine_that_allocates_a_routine(); PyObject *oA = PyArray_FromDimsAndData(rank, dims, PyArray_DOUBLE, (char *)A->array_data); PyObject *w = PyCObject_FromVoidPtr(A, free_myotherarraytype); ((PyArrayObject *)oA)->base = w; Now, when oA is DECREF'd latter, oA->base will also be DECREF'd. Since it's a PyCObject, free_myotherarraytype(A) will be called, free'ing the data. Since PyArray_FromDimsAndData was used, Python won't try to deallocate oA->data. I haven't checked whether this works under numarray (and I'm sure I saw a better way to do it there). I have used it for a Numeric<->Blitz++ wrapper. -- |>|\/|< /--------------------------------------------------------------------------\ |David M. Cooke http://arbutus.physics.mcmaster.ca/dmc/ |cookedm@physics.mcmaster.ca