Question

What is the fastest way to copy data from array b to array a, without modifying the address of array a. I need this because an external library (PyFFTW) uses a pointer to my array that cannot change.

For example:

a = numpy.empty(n, dtype=complex)
for i in xrange(a.size):
  a[i] = b[i]

It is possible to do it without a loop?

Answer 1

I believe

a = numpy.empty_like(b)
a[:] = b

will copy the values quickly. As Funsi mentions, recent versions of numpy also have the copyto function.