[Maxima-bugs] [maxima:bugs] Re: #4641 is does not work

[Stavros M. <mac...@us...>]

> I do not know why t[2] doesn't return a matrix.

Maxima defines a matrix as being composed of rows, each of which is a vector/list.
t[2] is the second row, and is a list, not a matrix.
If you want the second row as a matrix, you can use row(M,2), which gives a nx1 matrix, not a list. col(M,2) gives an 1xn matrix. But, beware! You can modify the parent matrix via the rows, but not via the columns.

I'd like to say that this is all beautifully designed, but frankly it was probably just an expedient way of implementing basic matrix functionality.




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**[bugs:#4641] is does not work**

**Status:** not-a-bug
**Group:** None
**Created:** Mon Dec 01, 2025 04:03 PM UTC by dan hayes
**Last Updated:** Wed Dec 03, 2025 10:33 PM UTC
**Owner:** nobody


build_info()  or bug_report()
"branch_5_44_base_231_g5c411f69f",timestamp="2021-01-12 23:51:42",host="x86_64-w64-mingw32",lisp_name="SBCL",lisp_version="2.0.0",maxima_userdir="C:/Users/zmth1/maxima",maxima_tempdir="C:/Users/zmth1/AppData/Local/Temp",maxima_objdir="C:/Users/zmth1/maxima/binary/branch_5_44_base_231_g5c411f69f/sbcl/2_0_0",maxima_frontend="wxMaxima",maxima_frontend_version="20.12.2-DevelopmentSnapshot_MSW_OpenMP201511+Locks")

(t:matrix([1],[2]),t,t[2],is( t[2]>0));   

and it comes back with unknown



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