Segmentation Error

General Discussion
1

Hello,
I came across a segmentation fault when trying to run membrane program in the documentation. I have compiled Freefem++ 4.6 on Xubuntu 20.04.
Any ideas on how to solve this?
Thank you.

real theta = 4.*pi/3.;
real a = 2.; //The length of the semimajor axis
real b = 1.; //The length of the semiminor axis
func z = x;

// Mesh
border Gamma1(t=0., theta){x=a*cos(t); y=b*sin(t);}
border Gamma2(t=theta, 2.*pi){x=a*cos(t); y=b*sin(t);}
mesh Th = buildmesh(Gamma1(100) + Gamma2(50));

// Fespace
fespace Vh(Th, P2); //P2 conforming triangular FEM
Vh phi, w, f=1;

// Solve
solve Laplace(phi, w)
	= int2d(Th)(
		dx(phi)*dx(w)
		+ dy(phi)*dy(w)
	)
	- int2d(Th)(
		f*w
	)
	+ on(Gamma1, phi=z);

// Plot
plot(phi, wait=true, ps="membrane2.eps"); //Plot phi
plot(Th, wait=true, ps="membraneTh2.eps"); //Plot Th

// Save mesh
savemesh(Th,"Th2.msh");

segmentation_fault

2

Hi
Add fill=true option to your plot.
This is a bug with Ubuntu, probably related to openGL, I reported in this thread

1 Like
3

I think, the graphic part (ffglut) trap, because the freefem++ end normal.
I have try with the last version 4.10 not problem on my MacOS

  1. test without graphic
  2. reinstall FreeFEM may be.