Hello everybody! Please have a look at the program below: # start import numpy t_array=numpy.ones(2048, dtype=numpy.float32) sinc_array=numpy.array((len(t_array),),dtype=numpy.float32) sinc_array[(t_array > 0.)]=1.0 # end If you execute this program, it crashes with Segmentation Fault or *** glibc detected *** python: double free or corruption (out): 0x081fe470 *** It depends on the circumstances, which error occurs, e.g. you must quit your interpreter if you are in interactvie mode. Obviously numpy.array() should be numpy.zeros() or numpy.empty() .... But this program should not crash with a core dump. Used Linux Versions are: Debian Testing with numpy 1.0.3, Debian Stable with numpy 1.0.1, Ubuntu Linux 6.10 with numpy 1.0 Also numpy-1.0.4 crashes. Yours, Achim