Re: New cgal4gp repo — Make CGAL functionality available for PARI/GP.

[hermann@stamm-wilbrandt.de]

On 2024-07-13 23:11, hermann@stamm-wilbrandt.de wrote:
> I started with that code, eliminated stuff I did not need, changed to 
> use g++
> instead of gcc because of CGAL, and have vertical prototype now:
> https://github.com/Hermann-SW/cgal4gp
>
> So nice, I will provide more functionality, but it works already:
> ...
I had completed all 7 CGAL Width_3 related functions for PARI/GP and 
thought I was done:
hermann@7600x:~/cgal4gp$ cat cgal4gp.gp
\\ 
https://doc.cgal.org/latest/Polytope_distance_d/classCGAL_1_1Width__3.html
\\
install("Width",                           "vG",     "CGAL_Width",       
                    "./libcgal4gp.so");

install("get_squared_width",               "v&&",    
"CGAL_get_squared_width",               "./libcgal4gp.so");
install("get_width_planes",                "v&&",    
"CGAL_get_width_planes",                "./libcgal4gp.so");
install("get_width_coefficients",          "v&&&&&", 
"CGAL_get_width_coefficients",          "./libcgal4gp.so");
install("get_build_direction",             "m",      
"CGAL_get_build_direction",             "./libcgal4gp.so");
install("get_all_build_directions",        "v&",     
"CGAL_get_all_build_directions",        "./libcgal4gp.so");
install("get_number_of_optimal_solutions", "i",      
"CGAL_get_number_of_optimal_solutions", "./libcgal4gp.so");
hermann@7600x:~/cgal4gp$

This is from my application I did all that for:
hermann@7600x:~/cgal4gp$ tail tqf_width.gp  | head -8
        print("#S=",#S);
        CGAL_Width(S);
        CGAL_get_squared_width(num,denom);
        print("squared width: ",num/denom," [",num,"/",denom,"]");
        print("build direction: ",CGAL_get_build_direction());
        print("optimal solutions: 
",CGAL_get_number_of_optimal_solutions());
        CGAL_get_all_build_directions(dir);
        print("workaround(all build directions): ", 
Set([d/gcd(d)*if(d[1]<0,-1,1) | d<-dir]));
hermann@7600x:~/cgal4gp$


Then 2 days ago I learned about CGAL Qt based Basic Viewer (2D and 3D), 
with interaction.
I know that GP can draw functions, but am not sure whether it has 3D 
output.
So I tried to get CGAL Basic Viewer running from GP.
Just succeeded, I have working vertical prototype — dirty, not nice, 
lots of todos, but working !

This is possible now from GP:

pi@raspberrypi5:~/qh $ gp -q BVcgal4.gp
? points=[[1, 0, 0], [2, -1, 0], [2, 0, -1], [3, 0, 0], [2, 1, 0], [2, 
0, 1]];
? CGAL_convex_hull_3(points)
[6, 12, 24, 8]
? CGAL_draw()
Using OpenGL context 4.5 GL


I recorded an animated .gif demonstrating all, find it in this posting:
https://forums.raspberrypi.com/viewtopic.php?p=2237908#p2237908


You can get some ideas of what becomes possible for GP on CGAL homepage:
https://www.cgal.org/


Regards,

Hermann.