[Numpy-discussion] Why the upcasting?

12 Jun 2002

      The sum of an Int32 array and a Float32 array is a Float64 array, as shown by the following code:

a = Numeric.array([1,2,3,4],'i')
a.typecode(), a.itemsize()

b = Numeric.array([1,2,3,4],'f')
b.typecode(), b.itemsize()

c=a+b
c.typecode(), c.itemsize()
...
...
...
a = Numeric.array([1,2,3,4],'i')
a.typecode(), a.itemsize()
('i', 4)
b = Numeric.array([1,2,3,4],'f')
b.typecode(), b.itemsize()
('f', 4)
c=a+b
c.typecode(), c.itemsize()
('d', 8)
Why is the upcasting?

I am using Linux/Pentium/python2.1/numpy20 .

Thanks.

Benyang Tang