Re: [Numpy-discussion] Really strange result

On Fri, May 1, 2009 at 7:39 PM, Charles R Harris wrote:

On Fri, May 1, 2009 at 7:24 PM, Neal Becker wrote:

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Charles R Harris wrote:

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On Fri, May 1, 2009 at 1:02 PM, Neal Becker wrote:

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In [16]: (np.linspace (0, len (x)-1, len(x)).astype (np.uint64)*2).dtype Out[16]: dtype('uint64')

In [17]: (np.linspace (0, len (x)-1, len(x)).astype (np.uint64)*n).dtype Out[17]: dtype('float64')

In [18]: type(n) Out[18]:

Now that's just strange. What's going on?

The n is signed, uint64 is unsigned. So a signed type that can hold uint64 is needed. There ain't no such integer, so float64 is used. I think the logic here is a bit goofy myself since float64 doesn't have the needed 64 bit precision and the conversion from int kind to float kind is confusing. I think it would be better to raise a NotAvailable error or some such. Lest you think this is an isolated oddity, sometimes numeric arrays can be converted to object arrays.

Chuck

I don't think that any type of integer arithmetic should ever be automatically promoted to float.

Besides that, what about the first example? There, I used '2' rather than 'n'. Is not '2' also an int?

What version of numpy are you using?

And what is the value of n? Chuck