10.04.2012 06:52, Travis Oliphant kirjoitti: [clip] > 4) I'm still not sure about whether the IGNORED > concept is necessary or not. I really like the separation > that was emphasized between implementation (masks versus > bit-patterns) and operations (propagating versus non-propagating). > Pauli even created another dimension which I don't totally grok > and therefore can't remember. Pauli? Do you still feel that > is a necessary construction?
I think the conclusion from that discussion subthread was only that retaining commutativity of binary operations is probably impossible, if unmasking of values is allowed. (I think in that discussion the big difference between IGNORED and MISSING was that ignored values could be unmasked while missing values could not.) If I recall correctly, my suggestion was that you might be able to rescue the situation by changing what assignment means, e.g. in `x[:5] = y` what gets written to `x` at the points where values in `x` and/or `y` are masked/ignored. But I think some counterexamples why this will not work as intended came up. `numpy.ma` operations are not commutative, which can be sometimes surprising, but apparently one just has to be pragmatical and live with this as there's no real way around it. I don't have very good suggestions on how these features should be designed --- I use them too seldom. Pauli _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion