# Error with restrict() and loaded mesh

**URL:** <https://community.freefem.org/t/error-with-restrict-and-loaded-mesh/3385>\
**Category:** General Discussion\
**Created:** [July 5, 2024, 12:14pm UTC](https://community.freefem.org/t/error-with-restrict-and-loaded-mesh/3385 "2024-07-05T12:14:43Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![etj](https://avatars.discourse-cdn.com/v4/letter/e/a698b9/32.png) [@etj](https://community.freefem.org/u/etj)\
**Post date:** [July 5, 2024, 12:14pm UTC](https://community.freefem.org/t/error-with-restrict-and-loaded-mesh/3385/1 "2024-07-05T12:14:43Z")

</div>

Hello,

I am having problems using `restrict()` with a mesh loaded with `loadDmesh()`. Here is a MWE that returns an error when either of the last 2 lines is not commented.  
Could you please tell me if I am doing something wrong, or if there is a problem with my installation?

> load “PETSc”  
> int[int] n2oSaved;  
> int[int] n2oLoaded;  
> {  
> macro dimension()2//  
> include “macro\_ddm.idp”  
> macro def(i)[i, i#B]//  
> macro init(i)[i, i]//  
> int[int] n2oTh;  
> macro ThN2O()n2oTh//  
> mesh Th = square(40, 40);  
> mesh ThGlobal = Th;  
> Mat A;  
> createMat(Th, A, [P1b,P1b])  
> saveDmesh(Th, “dump-2d”)  
> savemesh(ThGlobal, “dump-2d-G.mesh”);  
> fespace XhC(Th, P1b);  
> fespace VhC(Th, [P1b,P1b]);  
> fespace XhCGlob(ThGlobal, P1b);  
> fespace VhCGlob(ThGlobal, [P1b,P1b]);  
> int[int] restX = restrict(XhC, XhCGlob, n2oTh); // Ok  
> int[int] restV = restrict(VhC, VhCGlob, n2oTh); // Ok  
> }  
> {  
> macro dimension()2//  
> include “macro\_ddm.idp”  
> macro def(i)[i, i#B]//  
> macro init(i)[i, i]//  
> int[int] n2oTh;  
> macro ThN2O()n2oTh//  
> mesh Th;  
> fespace XhC(Th, P1b);  
> fespace VhC(Th, [P1b,P1b]);  
> loadDmesh(Th, “dump-2d”)  
> mesh ThGlobal;  
> ThGlobal = Th;  
> fespace XhCGlob(ThGlobal, P1b);  
> fespace VhCGlob(ThGlobal, [P1b,P1b]);  
> Mat A;  
> createMat(Th, A, [P1b,P1b])   
> //int[int] restX = restrict(XhC, XhCGlob, n2oTh); // Error here  
> //int[int] restV = restrict(VhC, VhCGlob, n2oTh); // Error here  
> }

The error message looks like this:

> Assertion fail : (kf \>= 0 && kf \<\> neF)  
> line :415, in file lgmat.cpp

Thank you!

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<div class="post-metadata">

**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\
**Post date:** [July 6, 2024, 5:05am UTC](https://community.freefem.org/t/error-with-restrict-and-loaded-mesh/3385/2 "2024-07-06T05:05:08Z")

</div>

Please make your code runnable when pasting a MWE. Your snippet needs to be edited, it cannot be run directly (issue with the double quotes). Anyway, the fix is:

```auto
--- original.edp	2024-07-06 07:03:39
+++ fixed.edp	2024-07-06 07:02:39
@@ -13,7 +13,7 @@ savemesh(ThGlobal, "dump-2d-G.mesh");
 Mat A;
 createMat(Th, A, [P1b,P1b])
 saveDmesh(Th, "dump-2d")
-savemesh(ThGlobal, "dump-2d-G.mesh");
+savemesh(ThGlobal, "dump-2d-G.msh");
 fespace XhC(Th, P1b);
 fespace VhC(Th, [P1b,P1b]);
 fespace XhCGlob(ThGlobal, P1b);
@@ -32,12 +32,11 @@ mesh ThGlobal;
 fespace XhC(Th, P1b);
 fespace VhC(Th, [P1b,P1b]);
 loadDmesh(Th, "dump-2d")
-mesh ThGlobal;
-ThGlobal = Th;
+mesh ThGlobal = readmesh("dump-2d-G.msh");
 fespace XhCGlob(ThGlobal, P1b);
 fespace VhCGlob(ThGlobal, [P1b,P1b]);
 Mat A;
 createMat(Th, A, [P1b,P1b])
-//int[int] restX = restrict(XhC, XhCGlob, n2oTh); // Error here
-//int[int] restV = restrict(VhC, VhCGlob, n2oTh); // Error here
+int[int] restX = restrict(XhC, XhCGlob, n2oTh); // Error here
+int[int] restV = restrict(VhC, VhCGlob, n2oTh); // Error here
 }

```

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<div class="post-metadata">

**Author:** ![etj](https://avatars.discourse-cdn.com/v4/letter/e/a698b9/32.png) [@etj](https://community.freefem.org/u/etj)\
**Post date:** [July 11, 2024, 10:35am UTC](https://community.freefem.org/t/error-with-restrict-and-loaded-mesh/3385/3 "2024-07-11T10:35:01Z")

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Thank you very much.