@Carl Love Sure, sorry

I am really a beginner ...

Thats is very useful for my work, thanks!

Thanks, that is exactly what I want, even if I am not able to understand the command

U:=U[..,p]

But I have learned the magic function "fnormal", thanks!

Just a question more:
can I get the (real) eigenvalues (and therefore the correspondig eigenvector) in decreasing order?

It works, thanks!

My matrix is a covariance matrix, so I cannot add the option shape=symmetric.

Thanks, they works!

For some reasons I need to name my variables x[1], x[2], ...

What if I don't know how many variables for the function f? That is, could I generalize the definition of Gf without knowing a priori how many variables there are?

@Preben Alsholm 

Right, thank you

@Preben Alsholm please, could you explain me what is "Maple notatio a.k.a., 1D input" and how can I set it? Thanks

Why crash and not an error message?  Moreover, look at this: why 22?

Download edges.mw

Clear

I was hoping that gcd between polynomials took the same time as numbers, actually 0 seconds :-)

Thank you

The cpu time is now 18 s, what does it mean?

Thanks,

as you can see r is the same in our computation, so I believe for p and q. 

My pc is an Intel Core i5, 2.7 GHz, 8 GB RAM; the ratio between our times is almost 60. 

I don't know if that could be the problem.

restart;
r:=randpoly(x, degree = 15);
p:=expand(r*randpoly(x, dense, degree=10^5)):
q:=expand(r*randpoly(x, dense, degree=10^5+20)):
                     10       9       3            
            r := 87 x   - 56 x  - 62 x  + 97 x - 73

CodeTools:-Usage(gcd(p,q));
memory used=70.30MiB, alloc change=35.88MiB, cpu time=57.41s, real time=57.71s, gc time=125.00ms

                   10       9       3            
               87 x   - 56 x  - 62 x  + 97 x - 73

p:=expand(r*randpoly(x, degree=10^6)):
q:=expand(r*randpoly(x, degree=10^5)):
CodeTools:-Usage(gcd(p,q));
memory used=54.22MiB, alloc change=-8.77MiB, cpu time=59.03s, real time=59.77s, gc time=140.62ms

                   10       9       3            
               87 x   - 56 x  - 62 x  + 97 x - 73

Hi,

the issue is solved. If you are interested in, the problem was the graphic card's driver of my laptop Lenovo Yoga L13 (the card is Intel Iris Xe Graphics).

After updating the driver now Maple (and Geogebra) work.