Mailman 3 September 2003 - NumPy-Discussion

sum and mean methods behaviour
by Peter Verveer 03 Sep '03

03 Sep '03

Hi All, I noticed that the sum() and mean() methods of numarrays use the precision of the given array in their calculations. That leads to resuls like this: >>> array([255, 255], Int8).sum() -2 >>> array([255, 255], Int8).mean() -1.0 Would it not be better to use double precision internally and return the correct result? Cheers, Peter -- Dr. Peter J. Verveer Cell Biology and Cell Biophysics Programme EMBL Meyerhofstrasse 1 D-69117 Heidelberg Germany Tel. : +49 6221 387245 Fax : +49 6221 387242 Email: Peter.Verveer(a)embl-heidelberg.de

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bug?
by Peter Verveer 02 Sep '03

02 Sep '03

Consider conversion of a slice using the astype() method: >>> a = array([[1,2],[3,4]]) >>> b = a[1, ...] >>> print b [3 4] Conversion using the astype() method goes wrong: >>> print b.astype(Float32) [ 1. 2.] This fixes it: >>> print b.copy().astype(Float32) [ 3. 4.] A bug? Cheers, Peter -- Dr. Peter J. Verveer Cell Biology and Cell Biophysics Programme EMBL Meyerhofstrasse 1 D-69117 Heidelberg Germany Tel. : +49 6221 387245 Fax : +49 6221 387242 Email: Peter.Verveer(a)embl-heidelberg.de

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type info
by Peter Verveer 01 Sep '03

01 Sep '03

Hi all, Is there some way in numarray to find out what the maximum and minimum values are that a type can hold? For instance, is there a convenient way to find out what the maximal possible value of the Float32 type is? Cheers, Peter -- Dr. Peter J. Verveer Cell Biology and Cell Biophysics Programme EMBL Meyerhofstrasse 1 D-69117 Heidelberg Germany Tel. : +49 6221 387245 Fax : +49 6221 387242 Email: Peter.Verveer(a)embl-heidelberg.de

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NumPy-Discussion September 2003