# General Discussion **URL:** https://community.freefem.org/c/general-discussion/7.md?page=37 [Latest](https://community.freefem.org/latest.md) · [Categories](https://community.freefem.org/categories.md) **Page:** 38 --- ## [In file Th\_quasibestprec5.msh, Erreur Lecture 6, good=0, bad=0, fail=4, eof=2 Line 40779](https://community.freefem.org/t/in-file-th-quasibestprec5-msh-erreur-lecture-6-good-0-bad-0-fail-4-eof-2-line-40779/2225)
**Author:** [@luca.liverotti](https://community.freefem.org/u/luca.liverotti)\ **Replies:** 1\ **Last updated:** [January 17, 2023, 2:38pm UTC](https://community.freefem.org/t/in-file-th-quasibestprec5-msh-erreur-lecture-6-good-0-bad-0-fail-4-eof-2-line-40779/2225 "2023-01-17T14:38:36Z")
Hi guys. Because of my research needs, I am trying to modify a mesh starting from the .msh file. The problem is the following: sometimes I have no problem when reading by using readmesh the .msh file I have created whi… --- ## [Boundary conditions information loss](https://community.freefem.org/t/boundary-conditions-information-loss/2227)
**Author:** [@mchetoui](https://community.freefem.org/u/mchetoui)\ **Replies:** 1\ **Last updated:** [January 17, 2023, 2:33pm UTC](https://community.freefem.org/t/boundary-conditions-information-loss/2227 "2023-01-17T14:33:15Z")
Hello everyone, I have a question about the definition of boundary conditions. The model that I try to implement is complex but I will use a simple model to introduce my problem. In a simple 2D Darcy model we can apply … --- ## [Freefem default precision](https://community.freefem.org/t/freefem-default-precision/2223)
**Author:** [@luca.liverotti](https://community.freefem.org/u/luca.liverotti)\ **Replies:** 1\ **Last updated:** [January 16, 2023, 4:01pm UTC](https://community.freefem.org/t/freefem-default-precision/2223 "2023-01-16T16:01:43Z")
Freefem default precision is 6, that is, if you want to printout a real variable, Freefem will show you not the real number with all digits in memory, but the real number with 6 significant digits. Does a way exist to c… --- ## [Getting iter/convergence info from hung solver](https://community.freefem.org/t/getting-iter-convergence-info-from-hung-solver/2221)
**Author:** [@marchywka](https://community.freefem.org/u/marchywka)\ **Replies:** 2\ **Last updated:** [January 16, 2023, 12:23pm UTC](https://community.freefem.org/t/getting-iter-convergence-info-from-hung-solver/2221 "2023-01-16T12:23:18Z")
I’ve setup a simple problem again ( 2 cubes in flowing air ) but with a different model equation. In setting it up, I have a few issues with boundary conditions. In one case, the thing seems to run forever with no … --- ## [Region and label](https://community.freefem.org/t/region-and-label/2217)
**Author:** [@marchywka](https://community.freefem.org/u/marchywka)\ **Replies:** 5\ **Last updated:** [January 16, 2023, 11:04am UTC](https://community.freefem.org/t/region-and-label/2217 "2023-01-16T11:04:48Z")
In movemesh23, the code I copied had a “region” parameter but I also added a “label” parameter that appears to work with the boundary conditions. Do these conflict or are they different? The resulting code seems to wor… --- ## [Problem to plot vector fields (Stokes problem)](https://community.freefem.org/t/problem-to-plot-vector-fields-stokes-problem/1496)
**Author:** [@Loic](https://community.freefem.org/u/Loic)\ **Replies:** 1\ **Last updated:** [January 16, 2023, 7:38am UTC](https://community.freefem.org/t/problem-to-plot-vector-fields-stokes-problem/1496 "2023-01-16T07:38:28Z")
Hello all, I am solving the Stokes Problem, // Fespace fespace Uh(ThRef, P1b); Uh u, v; Uh uu, vv; fespace Ph(ThRef, P1); Ph p, pp; // Problem solve stokes (\[u, v, p\], \[uu, vv, pp\]) = int2d(ThRef)( d… --- ## [Out of Bound problem after refining a 3D mesh](https://community.freefem.org/t/out-of-bound-problem-after-refining-a-3d-mesh/2196)
**Author:** [@Jacoban90](https://community.freefem.org/u/Jacoban90)\ **Replies:** 7\ **Last updated:** [January 14, 2023, 7:32pm UTC](https://community.freefem.org/t/out-of-bound-problem-after-refining-a-3d-mesh/2196 "2023-01-14T19:32:11Z")
Hello Freefem community: I’ve had recently problems when I apply local refinement in a 3D mesh using tetgreconstruction. The for loop in which the mesh is refined, is located inside of a while loop. Once the mesh is ref… --- ## [Tetgreconstruction goes to VM infinite loop likely, stack trace complains "badface"](https://community.freefem.org/t/tetgreconstruction-goes-to-vm-infinite-loop-likely-stack-trace-complains-badface/2218)
**Author:** [@marchywka](https://community.freefem.org/u/marchywka)\ **Replies:** 1\ **Last updated:** [January 14, 2023, 12:01am UTC](https://community.freefem.org/t/tetgreconstruction-goes-to-vm-infinite-loop-likely-stack-trace-complains-badface/2218 "2023-01-14T00:01:13Z")
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 … --- ## [Domain descomposition techniques for interfacial discontinuties](https://community.freefem.org/t/domain-descomposition-techniques-for-interfacial-discontinuties/2216)
**Author:** [@RodZ](https://community.freefem.org/u/RodZ)\ **Replies:** 0\ **Last updated:** [January 12, 2023, 9:15pm UTC](https://community.freefem.org/t/domain-descomposition-techniques-for-interfacial-discontinuties/2216 "2023-01-12T21:15:37Z")
Hi to everyone, I’m following the following example by Mc Bain: https://www.ljll.math.upmc.fr/hecht/ftp/ff++days/2012/McBain.pdf which works when the flux is the same, this is k\_1 \\frac{\\partial T}{\\partial n} = k\_2 \\f… --- ## [Need a border cube but it looks like flags in msh3.cpp commented out](https://community.freefem.org/t/need-a-border-cube-but-it-looks-like-flags-in-msh3-cpp-commented-out/2214)
**Author:** [@marchywka](https://community.freefem.org/u/marchywka)\ **Replies:** 2\ **Last updated:** [January 12, 2023, 9:12pm UTC](https://community.freefem.org/t/need-a-border-cube-but-it-looks-like-flags-in-msh3-cpp-commented-out/2214 "2023-01-12T21:12:48Z")
I could not ifind a way to make cube “holes” in a cubes mesh. I thought bcube may do that but looking here, plugin/seq/msh3.cpp, it looks like there may be flag bits for that but none seem to be coded in. Is there som… --- ## [Plot segvaults after several mesh adaptations](https://community.freefem.org/t/plot-segvaults-after-several-mesh-adaptations/2212)
**Author:** [@marchywka](https://community.freefem.org/u/marchywka)\ **Replies:** 6\ **Last updated:** [January 10, 2023, 4:23pm UTC](https://community.freefem.org/t/plot-segvaults-after-several-mesh-adaptations/2212 "2023-01-10T16:23:44Z")
I can’t upload the example since new users can’t upload apparently. so source included at bottom. Attached file appears to die in plot after several adaptations with the following stack trace, FreeFem++ FreeFem++ - v… --- ## [Adaptmesh and periodic boundary conditions](https://community.freefem.org/t/adaptmesh-and-periodic-boundary-conditions/2211)
**Author:** [@glimmt](https://community.freefem.org/u/glimmt)\ **Replies:** 0\ **Last updated:** [January 10, 2023, 5:00am UTC](https://community.freefem.org/t/adaptmesh-and-periodic-boundary-conditions/2211 "2023-01-10T05:00:30Z")
Hello, I am having problems with using adaptmesh with periodic boundary conditions. I found that others have experienced similar issues in the past, but I’m wondering if there is a solution in my case. Any help is appre… --- ## [Full parallel adaptmesh](https://community.freefem.org/t/full-parallel-adaptmesh/759)
**Author:** [@LucasPa](https://community.freefem.org/u/LucasPa)\ **Replies:** 11\ **Last updated:** [January 9, 2023, 5:21pm UTC](https://community.freefem.org/t/full-parallel-adaptmesh/759 "2023-01-09T17:21:56Z")
Hi! From several examples, I understood how to perform mesh adaptation. In particular in case of parallel example, I noticed that the following steps are taken: Compute the global solution from solutions on local mesh… --- ## [Address and location of source](https://community.freefem.org/t/address-and-location-of-source/2209)
**Author:** [@mahdi](https://community.freefem.org/u/mahdi)\ **Replies:** 1\ **Last updated:** [January 6, 2023, 10:58am UTC](https://community.freefem.org/t/address-and-location-of-source/2209 "2023-01-06T10:58:03Z")
Hi; I am trying to find the source files in Linux, (convect function for example). Can someone help me find where files are installed? --- ## [Start from last step](https://community.freefem.org/t/start-from-last-step/2208)
**Author:** [@mahdi](https://community.freefem.org/u/mahdi)\ **Replies:** 1\ **Last updated:** [January 6, 2023, 9:30am UTC](https://community.freefem.org/t/start-from-last-step/2208 "2023-01-06T09:30:09Z")
Hi; I am wondering if is there any way to Run FreeFem from a saved checkpoint? Thanks --- ## [Homogeneous Neumann Boundary condition](https://community.freefem.org/t/homogeneous-neumann-boundary-condition/318)
**Author:** [@paolopiers](https://community.freefem.org/u/paolopiers)\ **Replies:** 1\ **Last updated:** [December 28, 2022, 3:28pm UTC](https://community.freefem.org/t/homogeneous-neumann-boundary-condition/318 "2022-12-28T15:28:58Z")
Hello everyone, I was trying to implement in FreeFem the variational formulation for the biharmonic equation in H^2\_0(omega) (see Theorem 6.8-3 of P. G. Ciarlet - Linear and Nonlinear Functional Analysis with Applicatio… --- ## [Function problem](https://community.freefem.org/t/function-problem/2197)
**Author:** [@kuma](https://community.freefem.org/u/kuma)\ **Replies:** 2\ **Last updated:** [December 22, 2022, 2:47am UTC](https://community.freefem.org/t/function-problem/2197 "2022-12-22T02:47:58Z")
How to express jacobian elliptic function in ff. sn-1 is the inverse function of sn.k is a constant and I need to express the function y=snx. Thank you so much for any help. --- ## [Use of nodal coordinate in weak from equation](https://community.freefem.org/t/use-of-nodal-coordinate-in-weak-from-equation/2195)
**Author:** [@danmo](https://community.freefem.org/u/danmo)\ **Replies:** 2\ **Last updated:** [December 20, 2022, 3:48pm UTC](https://community.freefem.org/t/use-of-nodal-coordinate-in-weak-from-equation/2195 "2022-12-20T15:48:43Z")
Dear all, I am solving an elasticity problem, in which a uniform load (Ktensor) is applied to nodal points on the FE mesh. I put a brief version of my code for your reference. As you see below, I need to multiply the l… --- ## [What role does PoissonBoundary play?](https://community.freefem.org/t/what-role-does-poissonboundary-play/2194)
**Author:** [@jsmacd](https://community.freefem.org/u/jsmacd)\ **Replies:** 2\ **Last updated:** [December 19, 2022, 4:07pm UTC](https://community.freefem.org/t/what-role-does-poissonboundary-play/2194 "2022-12-19T16:07:31Z")
Would someone please kindly explain to me how this code works? It comes from the following example in the documentation: FreeFEM - Poisson. Particularly, I don’t understand how to interpret the matrix Poisson and Poisson… --- ## [Matrix-vector product in parallel](https://community.freefem.org/t/matrix-vector-product-in-parallel/2189)
**Author:** [@edelgado](https://community.freefem.org/u/edelgado)\ **Replies:** 6\ **Last updated:** [December 16, 2022, 12:46pm UTC](https://community.freefem.org/t/matrix-vector-product-in-parallel/2189 "2022-12-16T12:46:31Z")
Dear FreeFem users, I’m interested in perform some matrix-vector matrix-matrix products in parallel. The matrices, in general, come from varf and interpolate, and vectors are the solutions of FE problems. Right now it s… --- ## [Save solution with savehdf5sol in subdirectory](https://community.freefem.org/t/save-solution-with-savehdf5sol-in-subdirectory/2190)
**Author:** [@fvgt](https://community.freefem.org/u/fvgt)\ **Replies:** 0\ **Last updated:** [December 15, 2022, 5:24pm UTC](https://community.freefem.org/t/save-solution-with-savehdf5sol-in-subdirectory/2190 "2022-12-15T17:24:21Z")
Dear FreeFem++ users and developpers, Is it possible to use savehdf5sol to write a finite element function in a subdirectory ? Let me explain. If I do: load "iohdf5" system("mkdir -p result"); mesh Th = square(10,10);… --- ## [Integral probelm](https://community.freefem.org/t/integral-probelm/2187)
**Author:** [@Kellen](https://community.freefem.org/u/Kellen)\ **Replies:** 0\ **Last updated:** [December 15, 2022, 9:32am UTC](https://community.freefem.org/t/integral-probelm/2187 "2022-12-15T09:32:45Z")
--- ## [On the boundary condition resembling Robin boundary condition](https://community.freefem.org/t/on-the-boundary-condition-resembling-robin-boundary-condition/2145)
**Author:** [@zhugp123](https://community.freefem.org/u/zhugp123)\ **Replies:** 13\ **Last updated:** [December 14, 2022, 11:08am UTC](https://community.freefem.org/t/on-the-boundary-condition-resembling-robin-boundary-condition/2145 "2022-12-14T11:08:18Z")
I am trying to solve a problem resembling \\Delta \\mathbf{u} = 0, \\;\\;\\Delta c = 0, with the boundary condition \\mathbf{u} = \\nabla c and \\mathbf{n} \\cdot \\nabla c =0, where \\mathbf{n} is the normal vector of the boun… --- ## [Issue in the Additive Schwarz method](https://community.freefem.org/t/issue-in-the-additive-schwarz-method/2052)
**Author:** [@AbuAzzan](https://community.freefem.org/u/AbuAzzan)\ **Replies:** 4\ **Last updated:** [December 13, 2022, 11:33am UTC](https://community.freefem.org/t/issue-in-the-additive-schwarz-method/2052 "2022-12-13T11:33:01Z")
Hi According to the following Additive Schwarz method code, max (uold1,uold2) is to be set on the internal boundaries of both subproblems. But as you know, we can not compare and take the maximum of two vectors unless a… --- ## [Summing func variables](https://community.freefem.org/t/summing-func-variables/2147)
**Author:** [@jsmacd](https://community.freefem.org/u/jsmacd)\ **Replies:** 6\ **Last updated:** [December 12, 2022, 10:57pm UTC](https://community.freefem.org/t/summing-func-variables/2147 "2022-12-12T22:57:54Z")
Is it possible to define a function in a loop. For example, I want something like: func loopFunc = 0; for(int i = 2; i \< m; i++){ a = il-w; b = il+w; cout \<\< "a = " \<\< a \<\< ", b = " \<\< b \<\< endl; loopFunc += (abs(… --- ## [Linear elasticity of a ring with two mechanical properties](https://community.freefem.org/t/linear-elasticity-of-a-ring-with-two-mechanical-properties/2182)
**Author:** [@Yinghan](https://community.freefem.org/u/Yinghan)\ **Replies:** 3\ **Last updated:** [December 12, 2022, 8:49pm UTC](https://community.freefem.org/t/linear-elasticity-of-a-ring-with-two-mechanical-properties/2182 "2022-12-12T20:49:29Z")
Hi, guys I’m trying to do an elastic simulation on a ring with an insertion to it, which ends up with the ring having two different mechanical properties. I wonder how should I assign different properties to different … --- ## [Corner vertice change value with the order of on() function](https://community.freefem.org/t/corner-vertice-change-value-with-the-order-of-on-function/2173)
**Author:** [@recepute](https://community.freefem.org/u/recepute)\ **Replies:** 1\ **Last updated:** [December 9, 2022, 8:29pm UTC](https://community.freefem.org/t/corner-vertice-change-value-with-the-order-of-on-function/2173 "2022-12-09T20:29:58Z")
If I change the order of Dirichlet boundary with the Dirichlet condition function on() the value of the vertices on corner change. The problem is a Laplace problem, with value 500 on the button and 0 at the rest. //… --- ## [Min/Max over a domain](https://community.freefem.org/t/min-max-over-a-domain/2013)
**Author:** [@mrbenson](https://community.freefem.org/u/mrbenson)\ **Replies:** 6\ **Last updated:** [December 9, 2022, 10:53am UTC](https://community.freefem.org/t/min-max-over-a-domain/2013 "2022-12-09T10:53:01Z")
Hello, Is there an easy way to get the min/max values of a scalar field on a specific sub-domain defined by a list of tags ? Something like int1d : Min(Th,tags)(u) ? Thanks. --- ## [How to build a structured mesh?](https://community.freefem.org/t/how-to-build-a-structured-mesh/2175)
**Author:** [@Christian](https://community.freefem.org/u/Christian)\ **Replies:** 4\ **Last updated:** [December 8, 2022, 7:03pm UTC](https://community.freefem.org/t/how-to-build-a-structured-mesh/2175 "2022-12-08T19:03:55Z")
Hi everyone! Can you suggest to me a way for having a structured mesh for my geometry? The system’s geometry is a honeycomb-like shape. Initilly i tried with just one hexagon: I have made a first mesh with the command… --- ## [On defining functions with func](https://community.freefem.org/t/on-defining-functions-with-func/2165)
**Author:** [@Yangshen](https://community.freefem.org/u/Yangshen)\ **Replies:** 3\ **Last updated:** [December 8, 2022, 3:59pm UTC](https://community.freefem.org/t/on-defining-functions-with-func/2165 "2022-12-08T15:59:14Z")
Hello everyone In the following example, some optimization algorithms in NLOPT are called to solve the extreme value problem. There is a piece of code that I don’t understand. int NN = 6; load"medit" mesh Th = square… [Previous page](https://community.freefem.org/c/general-discussion/7.md?page=36) [Next page](https://community.freefem.org/c/general-discussion/7.md?page=38)