cdef extern from "math.h" nogil :
    cdef float sinf(float)
    cdef float cosf(float)
    cdef float sqrtf(float)

cdef extern from "stdlib.h" nogil :
    ctypedef unsigned int size_t
    cdef void* malloc (size_t)
    cdef void  free   (void* )
    cdef void* memcpy(void*, void*, int)