On Sat, Jun 21, 2008 at 15:49, Stéfan van der Walt <[EMAIL PROTECTED]> wrote: > 2008/6/20 Robert Kern <[EMAIL PROTECTED]>: >>> Are they initializing different copies of the same thing? >> >> No. "import numpy" is essentially the same as the pure Python >> equivalent; it loads the module and puts it into the namespace. >> cnp.import_array() loads the module (or reuses the already loaded >> one), does not put it into any namespace, but then, most importantly, >> grabs the pointer to the table of function pointers and assigns it to >> the local void** variable. All of the numpy API is made available to >> third-party extension modules by #define macros which look up into >> this table. > > Since "import numpy" already sets up the pointer table, is it then > necessary to use import_array?
None of the third party extension modules have a reference to it. import_array() grabs the pointer to the start of the pointer table and assigns it to a void** variable *local* to the extension module. Each extension module has its own and needs it to be set up via import_array(). "import numpy" sets up the table, but does not expose it. import_array() does not set up the table itself, but rather exposes it to the extension module. -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
