Mailman 3 December 2002 - NumPy-Discussion

Two bugs in numerictypes.py
by Edward C. Jones 23 Jan '03

23 Jan '03

In "numerictypes.py' it says "This module is designed so 'from numerictypes import *' is safe." When I "import numerictypes", and run dir(), I get: ['Any', 'AnyType', 'Bool', 'BooleanType', 'Byte', 'Complex', 'Complex32', 'Complex64', 'ComplexType', 'Double', 'Float', 'Float32', 'Float64', 'FloatingType', 'Int', 'Int16', 'Int32', 'Int64', 'Int8', 'IntegralType', 'Long', 'MAX_ALIGN', 'NumericType', 'Short', 'SignedIntegralType', 'SignedType', 'UInt16', 'UInt32', 'UInt64', 'UInt8', 'UnsignedIntegralType', 'UnsignedType', '__builtins__', '__doc__', '__name__', 'genericCoercions', 'genericPromotionExclusions', 'genericTypeRank', 'inttype1', 'inttype2', 'kind', 'mapto', 'maptype1', 'maptype2', 'nt1', 'nt2', 'ntypesize1', 'ntypesize2', 'numinclude', 'outtype', 'pythonTypeMap', 'pythonTypeRank', 'rank1', 'rank2', 'scalarTypeMap', 'signedtype1', 'signedtype2', 'typeDict', 'typecode', 'typecodes'] A bunch of leading "_" are needed. ---------------- My code is: #! /usr/bin/env python from numerictypes import UInt8 print UInt8 == "ABC" The message is: Traceback (most recent call last): File "./silly02.py", line 5, in ? print UInt8 == "ABC" File "/usr/lib/python2.2/site-packages/numarray/numerictypes.py", line 101, in __cmp__ other = typeDict[other] KeyError: ABC I would expect that the only object == to UInt8 be itself. Maybe add a function comparetypecodes(x, y) which returns True iff x and y are either NumericType's or strings which represent the same type.

3 4

Bin selection
by Magnus Lie Hetland 16 Jan '03

16 Jan '03

I have a set of limits, e.g. array([0, 35, 45, 55, 75]) and I want to use these to "classify" a set of numbers (another one-dimensional array). The "class" is the number of the first limit that is lower than or equal to the number I want to classify. E.g. I'd classify 17 as 0 and 42 as 1. My current approach is: sum(nums[:,NewAxis] >= lims, dim=-1) It seems a bit unnecessary to compare each number with all the limits when O(log(n)) would suffice (the limits are ordered); or even with O(n) running time, a smarter implementation could get an average of n/2 comparisons... Suggestions? -- Magnus Lie Hetland http://hetland.org

7 15

Re: [Numpy-discussion] argsort on CharArrays?
by Todd Miller 31 Dec '02

31 Dec '02

Magnus Lie Hetland wrote: >Todd Miller <jmiller(a)stsci.edu>: > > >>Magnus Lie Hetland wrote: >> >> >> >>>Is there any way to make argsort work on CharArrays? >>> >>> >>> >>Not yet. >> >> > >OK, thanks. > >(I don't mean to nag -- I'm just eager about numarray :) > > Don't worry about nagging. All this feedback is good. Results, however, may take a little time. >>Todd >> >> Todd

1 0

Lists in fromfile shape?
by Magnus Lie Hetland 31 Dec '02

31 Dec '02

I just noticed that the shape argument in fromfile cannot be an unhashable sequence. I assume tuples are the norm, but still -- it would be nice to accept other sequences? And... I also saw an explicit type check in fromfile, comparing _type(file) with _type("") -- what if I supplied some other string-like object? Perhaps a try/except with file+"" would be appropriate, to check for "string-like-ness" instead of an explicit type check? (I've just grown suspicious of typechecking in general...) Sorry if I'm being a pest, nagging about all these details, but I expect it may be useful to get them resolved? :] -- Magnus Lie Hetland http://hetland.org

1 1

argsort on CharArrays?
by Magnus Lie Hetland 31 Dec '02

31 Dec '02

Is there any way to make argsort work on CharArrays? -- Magnus Lie Hetland http://hetland.org

2 1

PEP 242 Numeric kinds
by Paul F Dubois 30 Dec '02

30 Dec '02

We had put off consideration of PEP 242 Numeric kinds until June 2002 when a meeting of some interested parties was to occur but the meeting didn't occur. I have a draft implementation and users of it but my feeling is that although correct and useful the PEP is not useful enough to put it in the standard library. Since it really only interests scientific programmers I propose simply making it a separate deliverable on the Numeric site and withdrawing the PEP.

6 7

Yet another bug
by Magnus Lie Hetland 30 Dec '02

30 Dec '02

Hi, there... I just found another bug :] from numarray import arange from __future__ import division arange(10) / 10 ... This will give an error. I really think this "real" division should be supported for arrays... -- Magnus Lie Hetland http://hetland.org

2 1

Compiling from CVS?
by Magnus Lie Hetland 30 Dec '02

30 Dec '02

I guess I'm just missing something obvious here: How do I compile numarray from the cvs dist? It seems like files such as numconfig.h etc. are missing -- it seems to have been generated by setup.py in the normal distributions, but I'm not sure how to do that... I just expected "python setup.py build" to work :] -- Magnus Lie Hetland http://hetland.org

2 1

indices with list arg?
by Magnus Lie Hetland 30 Dec '02

30 Dec '02

Why isn't indices([42]) (or foo.setshape([42]), for that matter) allowed? Overzealous type checking, or a necessity of the C code? -- Magnus Lie Hetland http://hetland.org

2 2

average()...?
by Magnus Lie Hetland 29 Dec '02

29 Dec '02

Just a quick question (which I believe I have asked before sometime, but I don't recall the outcome ;) -- why is the average() function from MaskedArray not available in numarray? It seems like a very useful function? It seems that looking through the list of functions in MaskedArray might be useful in finding candidates for numarray, in so far as they differ. (Wouldn't be logical if they supported the same functions, more or less?) For example, MaskedArray has the function count(), which counts the number of elements in an array -- exactly what was asked for yesterday, IIRC. (The use may be more obvious for masked arrays, where it counts non-masked elements, but it works on plain arrays too.) If nothing else, perhaps it would be possible to put from MA import count, average in numarray.py? (And similarly for other functions that may be missing in numarray -- I didn't check that closely.) Of course this wouldn't work if MA isn't available... :/ -- Magnus Lie Hetland http://hetland.org

1 0