On Sun, May 8, 2011 at 7:22 PM, Paul Anton Letnes < paul.anton.let...@gmail.com> wrote:
> > On 8. mai 2011, at 17.32, Warren Weckesser wrote: > > > > > > > On Sun, May 8, 2011 at 7:23 PM, Charles R Harris < > charlesr.har...@gmail.com> wrote: > > > > > > On Sun, May 8, 2011 at 3:15 PM, Paul Anton Letnes < > paul.anton.let...@gmail.com> wrote: > > Hi, > > > > it seems that I have found a bug in numpy.ndarray. numpy 1.5.1, python > 2.7.1 from macports on mac os x 10.6.7. I got the same error on Fedora 14 > with numpy 1.4.1 and python 2.7. Appending a [0] to the last line solves the > problem. > > > > % python testcrash.py > > [14:13:27 on 11-05-08] > > <type 'numpy.ndarray'> [ 12.+0.1j] > > <type 'numpy.ndarray'> [ 1.+0.1j] > > complex128 > > Traceback (most recent call last): > > File "testcrash.py", line 11, in <module> > > A[0] = A[0] + (eps1 - eps2) > > TypeError: can't convert complex to float > > > > % cat testcrash.py > > #!/usr/bin/env python > > > > import numpy > > > > A = numpy.zeros(10, dtype=numpy.complex128) > > eps1 = numpy.complex128([12.0 + 0.1j]) > > eps2 = numpy.complex128([1.0 + 0.1j]) > > > > It's the brackets, numpy.complex128([1.0 + 0.1j]) is a 1d array, not a > scalar. The error message is less than helpful though. > > > > > > > > But the same pattern works fine with float64: > > > > In [2]: x = array([1.0, 2.0]) > > > > In [3]: y = array([10.0]) > > > > In [4]: x[0] = y # Works > > > > In [5]: a = array([1.0, 2.0], dtype=complex128) > > > > In [6]: b = array([10.0 + 1j]) > > > > In [7]: a[0] = b # Error > > > --------------------------------------------------------------------------- > > TypeError Traceback (most recent call > last) > > > > /Users/warren/<ipython console> in <module>() > > > > TypeError: can't convert complex to float > > > > > > Something is fishy about that. > > > I agree. One thing is if arrays don't support this kind of assignment, but > behavior should be the same for complex and float. IMHO. > > Seems that it works for most types as long as there is just one element: In [1]: a = ones(10) In [2]: b = ones((1,1,1,1)) In [3]: a[0] = b So that seems to be the standard. IMHO, most uses of this sort are likely to be programming errors, but there it is. Chuck
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