# Tetgreconstruction goes to VM infinite loop likely, stack trace complains "badface"

**URL:** <https://community.freefem.org/t/tetgreconstruction-goes-to-vm-infinite-loop-likely-stack-trace-complains-badface/2218>\
**Category:** General Discussion\
**Created:** [January 13, 2023, 10:04pm UTC](https://community.freefem.org/t/tetgreconstruction-goes-to-vm-infinite-loop-likely-stack-trace-complains-badface/2218 "2023-01-13T22:04:49Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![marchywka](https://avatars.discourse-cdn.com/v4/letter/m/ee59a6/32.png) [@marchywka](https://community.freefem.org/u/marchywka)\
**Post date:** [January 13, 2023, 10:04pm UTC](https://community.freefem.org/t/tetgreconstruction-goes-to-vm-infinite-loop-likely-stack-trace-complains-badface/2218/1 "2023-01-13T22:04:49Z")

</div>

Trying to reconstruct the mesh results in an apparent infinite loop and eventual  
use of all memory ( I had to wait minutes for system to come back to write this ).  
Before it died, I caught a few stacks in the debugger and one suggested something  
about bad faces. The code is below. Any thoughts? Thanks.

#0 0x00007ffff38ec4c7 in tetgenmesh::insertpoint(double\*, tetgenmesh::triface\*, tetgenmesh::face\*, tetgenmesh::face\*, tetgenmesh::insertvertexflags\*) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#1 0x00007ffff39069fb in tetgenmesh::split\_tetrahedron(tetgenmesh::triface\*, double\*, int, int, tetgenmesh::insertvertexflags&) () from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#2 0x00007ffff39076b1 in tetgenmesh::repairbadtets(double, int) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#3 0x00007ffff3908931 in tetgenmesh::delaunayrefinement() ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#4 0x00007ffff3921718 in tetrahedralize(tetgenbehavior\*, tetgenio\*, tetgenio\*, tetgenio\*, tetgenio\*) () from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#5 0x00007ffff39236a5 in tetrahedralize(char\*, tetgenio\*, tetgenio\*, tetgenio\*, tetgenio\*) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#6 0x00007ffff388acba in ReconstructionRefine\_tetgen (  
switch\_tetgen=switch\_tetgen@entry=0x1541aa0 “raAQ”, Th3=…, nbhole=@0x7fffffffa9a0: 0,  
tabhole=, nbregion=@0x7fffffffa9a4: 1, tabregion=,  
nbfacecl=@0x7fffffffa9a8: 0, tabfacecl=0x15419d0, tsizevol=0x199bc10) at tetgen.cpp:1446  
#7 0x00007ffff389ea53 in ReconstructionRefine\_Op::operator() (this=0x1555ae0, stack=0x1538280)  
at tetgen.cpp:2159

#0 0x00007ffff3963c5f in insphere(double\*, double\*, double\*, double\*, double\*) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#1 0x00007ffff38c3044 in tetgenmesh::insphere\_s(double\*, double\*, double\*, double\*, double\*) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#2 0x00007ffff38fe8e4 in tetgenmesh::lawsonflip3d(tetgenmesh::flipconstraints\*) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#3 0x00007ffff3906b68 in tetgenmesh::split\_tetrahedron(tetgenmesh::triface\*, double\*, int, int, tetgenmesh::insertvertexflags&) () from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#4 0x00007ffff39076b1 in tetgenmesh::repairbadtets(double, int) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#5 0x00007ffff3908931 in tetgenmesh::delaunayrefinement() ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#6 0x00007ffff3921718 in tetrahedralize(tetgenbehavior\*, tetgenio\*, tetgenio\*, tetgenio\*, tetgenio\*) () from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#7 0x00007ffff39236a5 in tetrahedralize(char\*, tetgenio\*, tetgenio\*, tetgenio\*, tetgenio\*) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#8 0x00007ffff388acba in ReconstructionRefine\_tetgen (  
switch\_tetgen=switch\_tetgen@entry=0x1541aa0 “raAQ”, Th3=…, nbhole=@0x7fffffffa9a0: 0,  
tabhole=, nbregion=@0x7fffffffa9a4: 1, tabregion=,  
nbfacecl=@0x7fffffffa9a8: 0, tabfacecl=0x15419d0, tsizevol=0x199bc10) at tetgen.cpp:1446  
#9 0x00007ffff389ea53 in ReconstructionRefine\_Op::operator() (this=0x1555ae0, stack=0x1538280)  
at tetgen.cpp:2159

#0 0x00007ffff38c1c57 in tetgenmesh::memorypool::alloc() ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#1 0x00007ffff38c8170 in tetgenmesh::flippush(tetgenmesh::badface\*&, tetgenmesh::triface\*) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#2 0x00007ffff38f08dc in tetgenmesh::insertpoint(double\*, tetgenmesh::triface\*, tetgenmesh::face\*, tetgenmesh::face\*, tetgenmesh::insertvertexflags\*) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#3 0x00007ffff39069fb in tetgenmesh::split\_tetrahedron(tetgenmesh::triface\*, double\*, int, int, tetgenmesh::insertvertexflags&) () from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#4 0x00007ffff39076b1 in tetgenmesh::repairbadtets(double, int) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#5 0x00007ffff3908931 in tetgenmesh::delaunayrefinement() ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#6 0x00007ffff3921718 in tetrahedralize(tetgenbehavior\*, tetgenio\*, tetgenio\*, tetgenio\*, tetgenio\*) () from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#7 0x00007ffff39236a5 in tetrahedralize(char\*, tetgenio\*, tetgenio\*, tetgenio\*, tetgenio\*) ()  
from /home/ubuntu/dev/freefem/install/lib/ff++/4.12/lib/tetgen.so  
#8 0x00007ffff388acba in ReconstructionRefine\_tetgen (

///home/ubuntu/dev/freefem/FreeFem-sources-master/examples/3d$ vi Poisson-cube-ballon.edp  
//marchywka@happy:/home/ubuntu/dev/freefem/FreeFem-sources-master/examples/3d$

load “msh3”  
load “tetgen”  
load “medit”  
load “mshmet”

//  
real volumetet; // use in tetg.  
meshS Thx0,Thx1, Thy0, Thy1, Thz0, Thz1;  
int nx=10,ny=10,nz=10;  
func meshS mycube ( real x0, real x1, real y0,real y1, real z0, real z1, int orient, int lb)  
{  
meshS ThHex;  
// first build the 6 faces of the hex.  
//real x0=-1,x1=1;  
//real y0=-1.1,y1=1.1;  
//real z0=-1.2,z1=1.2;

// a volume of on tet.  
volumetet= (x1-x0)_(y1-y0)_(z1-z0)/ (nx_ny_nz) /6.;

mesh Thx = square(ny,nz,[y0+(y1-y0)\*x,z0+(z1-z0)\*y]);  
mesh Thy = square(nx,nz,[x0+(x1-x0)\*x,z0+(z1-z0)\*y]);  
mesh Thz = square(nx,ny,[x0+(x1-x0)\*x,y0+(y1-y0)\*y]);

int[int] refz=[0,5]; // bas  
int[int] refZ=[0,6]; // haut  
int[int] refy=[0,3]; // devant  
int[int] refY=[0,4]; // derriere  
int[int] refx=[0,1]; // gauche  
int[int] refX=[0,2]; // droite  
int f1=-1;  
int f2=1;  
if (orient==1) { f1=1; f2=-1; }  
int[int] l0=[0,lb+0];  
//meshS  
Thx0 = movemesh23(Thx,transfo=[x0,x,y],label=l0,orientation=f1,region=refx,removeduplicate=false);  
++l0[1];  
//meshS  
Thx1 = movemesh23(Thx,transfo=[x1,x,y],label=l0,orientation=f2,region=refX,removeduplicate=false);  
++l0[1];  
//meshS  
Thy0 = movemesh23(Thy,transfo=[x,y0,y],label=l0,orientation=f2,region=refy,removeduplicate=false);  
++l0[1];  
//meshS  
Thy1 = movemesh23(Thy,transfo=[x,y1,y],label=l0,orientation=f1,region=refY,removeduplicate=false);  
++l0[1];  
//meshS  
Thz0 = movemesh23(Thz,transfo=[x,y,z0],label=l0,orientation=f1,region=refz,removeduplicate=false);  
++l0[1];  
//meshS  
Thz1 = movemesh23(Thz,transfo=[x,y,z1],label=l0,orientation=f2,region=refZ,removeduplicate=false);

cout\<\<“l0=”\<\<l0\<\<endl;

//medit(" — ", Thx0,Thx1,Thy0,Thy1,Thz0,Thz1);  
ThHex = Thx0+Thx1+Thy0+Thy1+Thz0+Thz1;  
return ThHex;  
}

real x0=-1,x1=1; real yy0=-1.1,yy1=.1; real z0=-1.2,z1=.2;  
real xa0=-.5; real ya0=-.8; real za0=-1;  
real xb0=-.1; real yb0=-.8; real zb0=-1;  
real sz=.25;

meshS ThHex = mycube(x0,x1,yy0,yy1,z0,z1,1,0);  
real vol=volumetet;  
meshS Thsrc=Thx0;  
nx=10; ny=10; nz=10;  
meshS Tha = mycube(xa0,xa0+sz,ya0,ya0+sz,za0,za0+sz,-1,10);  
meshS Thb = mycube(xb0,xb0+sz,yb0,yb0+sz,zb0,zb0+sz,-1,20);  
meshS Thc= Tha+Thb+ThHex;  
//medit(" asdf ",Thc);

real[int] domaine = [-.9,-1,-1.1,.5,vol];  
mesh3 Th = tetg(Thc,switch=“pqaAAYYQ”,nbofregions=1,regionlist=domaine);  
// Tetrahelize the interior of the cube with tetgen  
//medit(“tetg”,Th,wait=1);

for( int i=0; i\<1; ++i)  
{  
cout\<\<" ++++++++++++++++++++++++++++++++++++ "\<\<i\<\<endl;  
fespace Xh(Th,P23d);  
Xh psi, wx,dxpsi,dypsi;  
macro grad(u) [dx(u),dy(u),dz(u)]// def of grad operator  
// Solve  
solve potential(psi, wx)  
= int3d(Th)(  
grad(psi)'_grad(wx)) // scalar product  
//+int2d(Thsrc) (2_wx)  
+int2d(Th,1) (.200_wx)  
+int2d(Th,2) (-.200_wx)  
//+on(Thl,psi=1)  
//+on(102,psi=1)  
+on(1,psi=0)  
//+on(1,psi=0)  
//+on(1,psi=1)  
//+on(3,dx(psi)=0)  
//+on(4,psi=1)  
//+on(5,psi=1)  
//+on(6,psi=1)  
;

dxpsi=dx(psi);  
dypsi=dy(psi);  
{  
ofstream ff(“psi.txt”);  
for (int ix = 0; ix \< Th.nv; ix++)  
{  
// this does produce dups, maybe confusing everything…  
for (int j = 0; j \< 3; j++) // foo[ix]+=Thx[ix][j]\*Thx[ix][j];  
//ff \<\< Th[ix][j].x \<\< " “\<\< Th[ix][j].y \<\< " " \<\< psi[Xh(ix,j)] \<\< endl;  
ff \<\< Th[ix][j].x \<\< " “\<\< Th[ix][j].y \<\< " "  
\<\<Th[ix][j].z\<\<” "  
\<\< dxpsi[Xh(ix,j)]\<\<” “\<\<dypsi[Xh(ix,j)]\<\<” "\<\<psi[Xh(ix,j)] \<\< endl;  
//ff \<\< Th[ix][0].x \<\< " " \<\< Th[ix][0].y \<\< " " \<\< psi[Xh(ix,0)] \<\< “\n\n\n”;  
}  
} // scoping

//real[int] viso=[1.2,1.15,1.1,1.02,1.01];  
//real[int] viso=[2,1.1,1.05,1.01,1,.999,.99,.9];  
//real[int] viso=[1.7,1.1,1,.999,.99,.9];  
real[int] viso=[0,.01,.05,.1,.2,.3];  
plot(psi, viso=viso, value=true, wait=1);  
//plot(psi, value=true, wait=1);  
//real[int] xxx=[dx(psi),dy(psi)];  
//plot(xxx, value=true, wait=1);

Xh hh; real lerr=.001;  
//hh=mshmet(Th,(dx(psi)\*dx(psi)+dy(psi)\*dy(psi)+dz(psi)\*dz(psi)),normalization=1,aniso=0,nbregul=1,hmin=Th.measure/100,hmax=Th.measure/10,err=lerr);

hh=mshmet(Th,psi,normalization=1,aniso=0,nbregul=1,hmin=Th.measure/100,hmax=Th.measure/10,err=lerr);

cout\<\<" +++++++++ RECO ++++++++++++++++++++ "\<\<i\<\<endl;  
// zero regions?  
Th=tetgreconstruction(Th,switch=“raAQ”,nbofregions=1,regionlist=domaine,sizeofvolume=hh_hh_hh/6.);

medit(“tetg”,Th,wait=1);  
} //i

---

<div class="post-metadata">

**Author:** ![marchywka](https://avatars.discourse-cdn.com/v4/letter/m/ee59a6/32.png) [@marchywka](https://community.freefem.org/u/marchywka)\
**Post date:** [January 14, 2023, 12:01am UTC](https://community.freefem.org/t/tetgreconstruction-goes-to-vm-infinite-loop-likely-stack-trace-complains-badface/2218/2 "2023-01-14T00:01:13Z")

</div>

This was probably just too fine of a refinement. Manually putting in  
differnt metrics seems to work. I went to mmg3d for now.