[Numpy-discussion] Time for beta1 of NumPy 1.0 (original) (raw)

David M. Cooke cookedm at physics.mcmaster.ca
Fri Jun 30 14:59:28 EDT 2006

On Fri, 30 Jun 2006 14:42:33 -0400 "Jonathan Taylor" <jonathan.taylor at utoronto.ca> wrote:

+1 for some sort of float. I am a little confused as to why Float64 is a particularly good choice. Can someone explain in more detail? Presumably this is the most sensible ctype and translates to a python float well?

It's "float64", btw. Float64 is the old Numeric name.

Python's "float" type is a C "double" (just like Python's "int" is a C "long"). In practice, C doubles are 64-bit.

In NumPy, these are the same type: float32 == single (32-bit float, which is a C float) float64 == double (64-bit float, which is a C double)

Also, some Python types have equivalent NumPy types (as in, they can be used interchangably as dtype arguments): int == long (C long, could be int32 or int64) float == double complex == cdouble (also complex128)

Personally, I'd suggest using "single", "float", and "longdouble" in numpy code.

[While we're on the subject, for portable code don't use float96 or float128: one or other or both probably won't exist; use longdouble].

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