#4331 The function part2cont of the sym module is unable to handle cases with multiple variables

[dao]

The bug can be verified by following codes:

(%i144)  pc: a*x^3+b*x^2*y+c*x*y^2+d*y^3+e;

(%o144) d*y^3+c*x*y^2+b*x^2*y+a*x^3+e
(%i145)  cont2part(pc, [x, y]);

(%o145) [[a,3,0],[b,2,1],[c,2,1],[d,3,0],[e,0,0]]
(%i146)  part2cont(%o145, [x, y]);

(%o146) c*x^2*y+b*x^2*y+d*x^3+a*x^3+e

Although the initial polynomial is bivariate in nature, the outcome of the part2cont function's operation is a polynomial in a single variable.

[dao]

Sorry, build info as follows

build_info(5.47.0 ,2024-02-17 13:24:51 ,x86_64-redhat-linux-gnu ,SBCL ,2.3.11-2.fc40 ,/home/xxx/.maxima ,/tmp ,/home/xxx/.maxima/binary/5_47_0/sbcl/2_3_11_2_fc40 ,false,false)

[Stavros Macrakis]

Thanks for the problem report. If you quote the code using three tildes before and after, it will format correctly, like this:

(%i144)  pc: a*x^3+b*x^2*y+c*x*y^2+d*y^3+e;

(%o144) d*y^3+c*x*y^2+b*x^2*y+a*x^3+e
(%i145)  cont2part(pc, [x, y]);

(%o145) [[a,3,0],[b,2,1],[c,2,1],[d,3,0],[e,0,0]]
(%i146)  part2cont(%o145, [x, y]);

(%o146) c*x^2*y+b*x^2*y+d*x^3+a*x^3+e

Otherwise, sourceforge/markdown interprets the asterisks as formatting rather than multiplication signs.

[dao]

Sorry, I don't know how to edit this issue contents. Any link available?

[Raymond Toy]

Click the "Edit" button here: