I don't know what exactly you are doing to make
an extra level of lists, but if you want to extract
the nth row of a matrix, try part(mat,n). I suppose
a column could be obtained by transposing first.
Is it perhaps the case that a column vector in
macsyma is not what you think , but a 2-d matrix
one of whose dimensions is 1?
RJF
David Holmgren wrote:
>
> Hi,
>
> I'm working on some routines for optimization using Maxima (e.g,
> second-order Newton method, Levenberg-Marquardt), and I've run into a
> problem with routines related to matrix manipulation. For example, when one
> solves a matrix equation A.x = b by using x:invert(A).b, x is a list of
> lists. So, when this is done in an iterative loop, the problem compounds
> itself so that on the next iteration one gets a list of list of lists, etc.
> Another example is when one forms a row vector by doing something like
> v:transpose([1,2,3]) - this also gives a list of lists. Is there any way of
> controlling or avoiding this behavior in Maxima? I am not yet sufficiently
> familiar with Maxima programming to see a way out of this.
>
> Many thanks for any advice, etc., on this.
>
> Sincerely,
>
> David Holmgren
>
> Dr. David E. Holmgren,
> Imaging Scientitst,
> SMART Technologies, Inc.
> Calgary, AB, Canada
> http://www.smarttech.com
> [403]-235-1452, ext. 251
> DavidHolmgren@smarttech.com
>
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