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