 | Loops over an array run slowly |
| Vectorization = replace explicit loops by functions calls such that the whole loop is implemented in C (or Fortran) |
| Explicit loops:
r = zeros(x.shape, x.dtype)
for i in xrange(x.size):
r[i] = sin(x[i])
|
| Vectorized version:
r = sin(x) |
| Arithmetic expressions work for both scalars and arrays |
| Many fundamental functions work for scalars and arrays |
| Ex: x**2 + abs(x) works for x scalar or array |
