JJ wrote: >Hello. For what its worth, as a newly ex-matlab user I would like to make a >few >suggestions on use of matrices in numpy. As per earlier discussions, I like >the >idea of being able to choose matrices as the default (vs arrays). But if >possible, it would be nice if all functions etc that took matrices also >returned >matrices. I know effort has been made on this. Here are my suggestions: > >1) is it possible to get the function unique() to work with matrices, perhaps >with a unique_rows() function to work with matrices of more than one column? > >2) It would be very convienient to have some simple way to delete selected >columns of a matrix. > This is a good idea. It would be nice to address it at some point. There is a Python syntax for it, but we are not using it yet:
del X[...] Of course one of the problems with this syntax (as opposed to a function that returns a new array) is that because X can share it's data with other arrays, you can't just re-size it's memory or other arrays depending on that chunk of memory will be in deep trouble. So, we are probably not going to be able to have a "syntax-style" delete. But, some kind of function that returns an array with specific entries deleted would be nice. >3) It would be nice if matrices could be used for iterations. For example, if >M >was a 1 x n matrix, it would be nice to be able to use: for i in M: and >iterate over the individual items in M. > > They can be used as iterators. The problem here is simply convention (rows are iterated over first). We could over-ride the iterator behavior of matrices, though to handle 1xn and nx1 matrices identically if that is desirable. >4) It would be nice if the linear algebra package and other packages returned >matrices if given matrices. For example, if M is a matrix, svd(M) now returns > > Svd returns matrices now. Except for the list of singular values which is still an array. Do you want a 1xn matrix instead of an array? -Travis ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Numpy-discussion mailing list Numpy-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/numpy-discussion
