# General Discussion **URL:** https://community.freefem.org/c/general-discussion/7.md?page=74 [Latest](https://community.freefem.org/latest.md) · [Categories](https://community.freefem.org/categories.md) **Page:** 75 --- ## [plotMPI, how to get plot display for parallelization hpddm](https://community.freefem.org/t/plotmpi-how-to-get-plot-display-for-parallelization-hpddm/162)
**Author:** [@Lihao](https://community.freefem.org/u/Lihao)\ **Replies:** 6\ **Last updated:** [October 31, 2019, 9:45am UTC](https://community.freefem.org/t/plotmpi-how-to-get-plot-display-for-parallelization-hpddm/162 "2019-10-31T09:45:16Z")
Dear developer, I am a beginner in parallelization. I tried to run the example code “elasticity-3d.edp” in hpddm folder. Please see the link: https://doc.freefem.org/documentation/parallelization.html#hpddm-solvers I … --- ## [How to secure my code?](https://community.freefem.org/t/how-to-secure-my-code/163)
**Author:** [@wael.wanis](https://community.freefem.org/u/wael.wanis)\ **Replies:** 0\ **Last updated:** [October 30, 2019, 10:20pm UTC](https://community.freefem.org/t/how-to-secure-my-code/163 "2019-10-30T22:20:55Z")
Hello everyone, I am designing a GUI using MATLAB to interface with my FreeFem++ code. Until now the GUI works properly only if the FreeFem++ file of the code exists in the same folder with the GUI file. However, my p… --- ## [How to identify the boundary label for an import mesh](https://community.freefem.org/t/how-to-identify-the-boundary-label-for-an-import-mesh/161)
**Author:** [@Lihao](https://community.freefem.org/u/Lihao)\ **Replies:** 2\ **Last updated:** [October 27, 2019, 7:20am UTC](https://community.freefem.org/t/how-to-identify-the-boundary-label-for-an-import-mesh/161 "2019-10-27T07:20:42Z")
Dear developers, I tried to use Implicit domain meshing MMG3D to get an adaptive mesh based on 0 value of the level-set function After reading the mesh into FreeFem++, I need to identify the boundary label in order to … --- ## [FFDDM/HPDDM and Stokes-Brinkman problem](https://community.freefem.org/t/ffddm-hpddm-and-stokes-brinkman-problem/160)
**Author:** [@salazardetroya](https://community.freefem.org/u/salazardetroya)\ **Replies:** 1\ **Last updated:** [October 24, 2019, 5:32am UTC](https://community.freefem.org/t/ffddm-hpddm-and-stokes-brinkman-problem/160 "2019-10-24T05:32:59Z")
So I am pretty excited about the capability in FreeFEM to solve problems with large contrast in the material properties through the FFDM/HPDDM solver (https://doc.freefem.org/documentation/ffddm/tutorial.html) So far in … --- ## [Domain decomposition and matrix free methods](https://community.freefem.org/t/domain-decomposition-and-matrix-free-methods/156)
**Author:** [@miguel](https://community.freefem.org/u/miguel)\ **Replies:** 1\ **Last updated:** [October 20, 2019, 3:28pm UTC](https://community.freefem.org/t/domain-decomposition-and-matrix-free-methods/156 "2019-10-20T15:28:34Z")
Can domain decomposition methods be used without having to assemble the operator? My concern is that there is a trend towards matrix free methods for very large scale problems. I wonder how domain decomposition deal with… --- ## [Munmap\_chunk error](https://community.freefem.org/t/munmap-chunk-error/151)
**Author:** [@e-aranda](https://community.freefem.org/u/e-aranda)\ **Replies:** 4\ **Last updated:** [October 15, 2019, 7:30am UTC](https://community.freefem.org/t/munmap-chunk-error/151 "2019-10-15T07:30:51Z")
Hello, I have installed FreeFem 4.4 from deb package, and it seems it is working fine, but once a script is finished I always get this error: munmap\_chunk(): invalid pointer Aborted core dumped Any hints? Thanks, Er… --- ## [Coupled partial differential equations](https://community.freefem.org/t/coupled-partial-differential-equations/150)
**Author:** [@reinoud](https://community.freefem.org/u/reinoud)\ **Replies:** 8\ **Last updated:** [October 10, 2019, 12:51pm UTC](https://community.freefem.org/t/coupled-partial-differential-equations/150 "2019-10-10T12:51:54Z")
I have 5 coupled partial differential equations in t and r ( second order). Is therre someone who can help me to implement these equations in FreeFem? I am new in FreeFem and used Mathematica. --- ## [Join us for the FreeFEM Days 11th edition in Paris!](https://community.freefem.org/t/join-us-for-the-freefem-days-11th-edition-in-paris/148)
**Author:** [@franck.lahaye](https://community.freefem.org/u/franck.lahaye)\ **Replies:** 0\ **Last updated:** [October 4, 2019, 1:40pm UTC](https://community.freefem.org/t/join-us-for-the-freefem-days-11th-edition-in-paris/148 "2019-10-04T13:40:57Z")
The conference will take place at Sorbonne University in Paris on the 17/18/19th of December. Register now by following the link on this page : https://freefem.org/ffdays The conference is free. If you can, please con… --- ## [Poisson problem on a manifold without boundary](https://community.freefem.org/t/poisson-problem-on-a-manifold-without-boundary/146)
**Author:** [@GaelleB](https://community.freefem.org/u/GaelleB)\ **Replies:** 2\ **Last updated:** [October 4, 2019, 6:26am UTC](https://community.freefem.org/t/poisson-problem-on-a-manifold-without-boundary/146 "2019-10-04T06:26:26Z")
Hello, I want to solve a classical Poisson problem on the standard torus : -\\Delta \\psi = \\phi Then I added some periodic conditions and adapted the mesh with the corresponding metric. It looks that the results are no… --- ## [Constant Boundary Condition](https://community.freefem.org/t/constant-boundary-condition/147)
**Author:** [@robin997](https://community.freefem.org/u/robin997)\ **Replies:** 0\ **Last updated:** [October 3, 2019, 4:16pm UTC](https://community.freefem.org/t/constant-boundary-condition/147 "2019-10-03T16:16:43Z")
Is there a way to specify a constant boundary condition (in 3d)? I am doing analysis (capacitance, voltage, etc) of a composite electrical component. So we know that inside a conductor, we have no electric field, thus c… --- ## [Does linfty give maximum norm?](https://community.freefem.org/t/does-linfty-give-maximum-norm/142)
**Author:** [@linwaytin](https://community.freefem.org/u/linwaytin)\ **Replies:** 2\ **Last updated:** [October 1, 2019, 1:30pm UTC](https://community.freefem.org/t/does-linfty-give-maximum-norm/142 "2019-10-01T13:30:02Z")
Hi, I noticed there is property of an array called linfty. It seems that this property gives maximum norm of an array. Is this right? I cannot find documentation for this property. Thank you. --- ## [Segfault with cube(50,50,150)](https://community.freefem.org/t/segfault-with-cube-50-50-150/143)
**Author:** [@ffeppon](https://community.freefem.org/u/ffeppon)\ **Replies:** 1\ **Last updated:** [October 1, 2019, 9:39am UTC](https://community.freefem.org/t/segfault-with-cube-50-50-150/143 "2019-10-01T09:39:32Z")
Dear FreeFEM developpers, I noticed I have a segfault with the last version d65848cee66a (branch develop) when I try to create a rather (moderately) large mesh load "msh3" load "medit"; mesh3 Th = cube(50, 50, 150, \[x… --- ## [Limit number of iterations in CG](https://community.freefem.org/t/limit-number-of-iterations-in-cg/134)
**Author:** [@BeniaminBogosel](https://community.freefem.org/u/BeniaminBogosel)\ **Replies:** 2\ **Last updated:** [September 10, 2019, 6:39am UTC](https://community.freefem.org/t/limit-number-of-iterations-in-cg/134 "2019-09-10T06:39:43Z")
Hello, Is it possible to limit the number of iterations when using the CG algorithm ? Best regards, Beniamin --- ## [Save cells data in TXT file](https://community.freefem.org/t/save-cells-data-in-txt-file/129)
**Author:** [@fffm\_84](https://community.freefem.org/u/fffm_84)\ **Replies:** 2\ **Last updated:** [September 8, 2019, 12:30pm UTC](https://community.freefem.org/t/save-cells-data-in-txt-file/129 "2019-09-08T12:30:54Z")
Hello everybody, I tried to save cells data of a mesh, in a text file, with the code: { ofstream file(“file.txt”); //file\<\<“CELLS”\<\ **Author:** [@glmiranda](https://community.freefem.org/u/glmiranda)\ **Replies:** 4\ **Last updated:** [September 7, 2019, 11:38pm UTC](https://community.freefem.org/t/how-can-i-calculate-the-cubic-root-of-a-negative-number/126 "2019-09-07T23:38:46Z") Hi!! I am obtaining a “nan” every time that x takes a negative value in pow(x,1./3.)? What am I doing wrong? Thank you!!! --- ## [Problem reading mesh when in MPI version](https://community.freefem.org/t/problem-reading-mesh-when-in-mpi-version/127)
**Author:** [@robin997](https://community.freefem.org/u/robin997)\ **Replies:** 0\ **Last updated:** [September 6, 2019, 4:24pm UTC](https://community.freefem.org/t/problem-reading-mesh-when-in-mpi-version/127 "2019-09-06T16:24:33Z")
How do I read a generated mesh in the MPI version? The documentation doesn’t talk about this… I use the command below to read the mesh. Normally it works fine. However, in MPI version, I encounter this error message. m… --- ## ["Change" function gives error on 3D mesh v 4.4](https://community.freefem.org/t/change-function-gives-error-on-3d-mesh-v-4-4/123)
**Author:** [@BeniaminBogosel](https://community.freefem.org/u/BeniaminBogosel)\ **Replies:** 1\ **Last updated:** [September 3, 2019, 9:30am UTC](https://community.freefem.org/t/change-function-gives-error-on-3d-mesh-v-4-4/123 "2019-09-03T09:30:16Z")
Hello, I had a code which worked fine under version 4.2 and which gives an assertion fail when trying to apply the “change” function to change the labels on a 3D mesh. Maybe it has something to do with the surface mesh. … --- ## [Microwave Imaging](https://community.freefem.org/t/microwave-imaging/122)
**Author:** [@mohammad](https://community.freefem.org/u/mohammad)\ **Replies:** 0\ **Last updated:** [August 31, 2019, 5:12pm UTC](https://community.freefem.org/t/microwave-imaging/122 "2019-08-31T17:12:10Z")
How to develop the basic algorithm for microwave imaging reconstruction algorithm in freefem++ . Anynone can share the code for microwave imaging or Do anybody know how to implement a freefem code for designing simple a… --- ## [Spherical cap mesh](https://community.freefem.org/t/spherical-cap-mesh/115)
**Author:** [@paolopiers](https://community.freefem.org/u/paolopiers)\ **Replies:** 2\ **Last updated:** [August 27, 2019, 11:55am UTC](https://community.freefem.org/t/spherical-cap-mesh/115 "2019-08-27T11:55:40Z")
Hello, I would like to ask you if you could tell me how to generate a mesh representing a spherical cap in FreeFem++. Thanks in advance. Paolo --- ## [Getting error giving the quadrature type explicitly](https://community.freefem.org/t/getting-error-giving-the-quadrature-type-explicitly/119)
**Author:** [@arousta](https://community.freefem.org/u/arousta)\ **Replies:** 2\ **Last updated:** [August 30, 2019, 5:57pm UTC](https://community.freefem.org/t/getting-error-giving-the-quadrature-type-explicitly/119 "2019-08-30T17:57:59Z")
When I use the qfe= option in int2d function I get error. It is fine if I use qforder= The program below: mesh Th = square(3,3); fespace Vh(Th,P1); Vh v=x; real s = int2d(Th,qfe=qf1pT)(v); Error: Impossible to cast \<… --- ## [Accessing material properties at local matrices building stage](https://community.freefem.org/t/accessing-material-properties-at-local-matrices-building-stage/121)
**Author:** [@PavelOganesyan](https://community.freefem.org/u/PavelOganesyan)\ **Replies:** 0\ **Last updated:** [August 30, 2019, 4:32pm UTC](https://community.freefem.org/t/accessing-material-properties-at-local-matrices-building-stage/121 "2019-08-30T16:32:02Z")
Hi! I’d like to make a fork of FreeFem and try to implement non-homogeneous materials support by changing material properties during local matrices computation process. I got a little confused about specific place where… --- ## [Plot/Export results on a curved surface (3d)](https://community.freefem.org/t/plot-export-results-on-a-curved-surface-3d/117)
**Author:** [@robin997](https://community.freefem.org/u/robin997)\ **Replies:** 0\ **Last updated:** [August 28, 2019, 3:28am UTC](https://community.freefem.org/t/plot-export-results-on-a-curved-surface-3d/117 "2019-08-28T03:28:28Z")
Is there a function to plot or export data on a labeled surface? (3d problem) (I want to plot fluid pressure as vectors on a deformed membrane surface) I could not find such a function in the documentation… In the surf… --- ## [Move mesh function inquiry](https://community.freefem.org/t/move-mesh-function-inquiry/116)
**Author:** [@robin997](https://community.freefem.org/u/robin997)\ **Replies:** 1\ **Last updated:** [August 27, 2019, 6:28am UTC](https://community.freefem.org/t/move-mesh-function-inquiry/116 "2019-08-27T06:28:46Z")
Hello, I have a question: Using the move mesh function, do the FE functions move with it, or is the mesh the only thing that is moved? For example, having a delta function d(x) = 1 only at x = 0. If I move mesh at x=… --- ## [Apply quadrature in a piecewise way](https://community.freefem.org/t/apply-quadrature-in-a-piecewise-way/114)
**Author:** [@arousta](https://community.freefem.org/u/arousta)\ **Replies:** 0\ **Last updated:** [August 19, 2019, 7:20pm UTC](https://community.freefem.org/t/apply-quadrature-in-a-piecewise-way/114 "2019-08-19T19:20:31Z")
For my problem I have two meshes, finer mesh by splitting the coarse one by half. I want to do an intalledges over the coarse mesh. As one field is defined on the fine mesh, I need the quadrature to be applied in a piec… --- ## [About generalized Stokes problem](https://community.freefem.org/t/about-generalized-stokes-problem/111)
**Author:** [@jueliang](https://community.freefem.org/u/jueliang)\ **Replies:** 0\ **Last updated:** [August 18, 2019, 7:28am UTC](https://community.freefem.org/t/about-generalized-stokes-problem/111 "2019-08-18T07:28:07Z")
Hi, when I try to solve the generallized Stokes problem, I find some Strange phenomena： The pressure error in the cornor is so large. And I don’t know where I was wrong. Who can help me point out the mistakes? Thanks a… --- ## [How to respond the "load error:gsl?](https://community.freefem.org/t/how-to-respond-the-load-error-gsl/110)
**Author:** [@nakaikiyohiko](https://community.freefem.org/u/nakaikiyohiko)\ **Replies:** 0\ **Last updated:** [August 14, 2019, 9:05pm UTC](https://community.freefem.org/t/how-to-respond-the-load-error-gsl/110 "2019-08-14T21:05:56Z")
Dear all, I am beginner of FreeFem++ version 4.3-1. When I run the FreeFem++ script which my colleague made by FreeFem++ version 3.5.6., the run was stop with the following message in command prompt. Could you please … --- ## [Import Data from MATLAB](https://community.freefem.org/t/import-data-from-matlab/109)
**Author:** [@wael.wanis](https://community.freefem.org/u/wael.wanis)\ **Replies:** 2\ **Last updated:** [August 11, 2019, 9:38am UTC](https://community.freefem.org/t/import-data-from-matlab/109 "2019-08-11T09:38:35Z")
Hello everyone, I am trying to implement a GUI using MATLAB AppDesigner, the user will insert some inputs using this GUI, I want to ask how can I import these data into the FreeFem, what type of file should I save these… --- ## [Improved doc for adding new finite element space](https://community.freefem.org/t/improved-doc-for-adding-new-finite-element-space/102)
**Author:** [@arousta](https://community.freefem.org/u/arousta)\ **Replies:** 1\ **Last updated:** [August 11, 2019, 7:28am UTC](https://community.freefem.org/t/improved-doc-for-adding-new-finite-element-space/102 "2019-08-11T07:28:48Z")
Hi, I know the guide for adding a new space in the documentation. Actually have read it many times, but still looks very cryptic. May I ask someone who understands the details to improve this part of the documentation … --- ## [Coefficients of basis functions](https://community.freefem.org/t/coefficients-of-basis-functions/106)
**Author:** [@fotios.kasolis](https://community.freefem.org/u/fotios.kasolis)\ **Replies:** 2\ **Last updated:** [August 8, 2019, 10:41pm UTC](https://community.freefem.org/t/coefficients-of-basis-functions/106 "2019-08-08T22:41:44Z")
Dear community, Is there a clever way to access the exact coefficients of the P1 basis functions? Regards, /Fotios Kasolis --- ## [Save time step solution progress to continue next run](https://community.freefem.org/t/save-time-step-solution-progress-to-continue-next-run/105)
**Author:** [@robin997](https://community.freefem.org/u/robin997)\ **Replies:** 2\ **Last updated:** [August 9, 2019, 12:09am UTC](https://community.freefem.org/t/save-time-step-solution-progress-to-continue-next-run/105 "2019-08-09T00:09:53Z")
Hi, Just wondering if anyone has tried saving their time-step progress to continue in a different run. I found that I could export solution data with “ffmatlib” and “iovtk”. However, “ffmatlib” doesn’t have the function… [Previous page](https://community.freefem.org/c/general-discussion/7.md?page=73) [Next page](https://community.freefem.org/c/general-discussion/7.md?page=75)