# Problem during factorization of a system of reaction diffusion equations

**URL:** <https://community.freefem.org/t/problem-during-factorization-of-a-system-of-reaction-diffusion-equations/1162>\
**Category:** General Discussion\
**Created:** [August 19, 2021, 12:49pm UTC](https://community.freefem.org/t/problem-during-factorization-of-a-system-of-reaction-diffusion-equations/1162 "2021-08-19T12:49:27Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Jacoban90](https://avatars.discourse-cdn.com/v4/letter/j/65b543/32.png) [@Jacoban90](https://community.freefem.org/u/Jacoban90)\
**Post date:** [August 19, 2021, 12:49pm UTC](https://community.freefem.org/t/problem-during-factorization-of-a-system-of-reaction-diffusion-equations/1162/1 "2021-08-19T12:49:27Z")

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Hello,

I was trying to represent the weak formula of the following system of reaction diffusion equations

![image](https://canada1.discourse-cdn.com/flex030/uploads/freefem/original/1X/f17c8f6759bc4162f225ac1fbed93c8d6c57684d.png)

Where the main variables Cm and Ce are the ester and monomer concentrations as you can see in the fórmula. The parameters K1, Ce and alpha are known (0.1 and 1 respectively)-

The boundary conditions are Cm =0 in the free surface and Ce=exp(-k1)\*t, which is a Dirchlet time dependent condition, in the same boundary(the second boundary condition was obtained by integrating the second equation of the system,substituting Cm by 0).

The initial conditions are Cm=0 and Ce=1.

I tried to derive the weak form of the two equations by multiplying them by thier respective test functions (v and w) and making the correspondent transformations.

problem reactiondiffusion(Cmn,Cen,v,w)=

int3d(Th,optimize=0)((Cmn/dt)\*v)  
+int3d(Th,optimize=0)((Cen/dt)\*v)

+int3d(Th,optimize=0)(f\*grad(Cmn)’\*grad(v))

-int3d(Th,optimize=0)((b+Cmnold/dt)_v)  
-int3d(Th,optimize=0)((-b+Cenold/dt)w)  
//-int3d(Th,optimize=0)(1e-20Cen_w)//Stabilization term

+on(Free, Cmn=0, Cen=g);

However once I execute the code i found the following error

On return from DMUMPS, INFOG(1)= -9  
On return from DMUMPS, INFOG(2)= 2076104  
Erreur Mumps seq: number -9  
Fatal Erreur MUMPS\_seq Factorize  
Entering DMUMPS 5.0.2 driver with JOB, N, NZ = -2 31200 874536  
current line = 78  
Exec error : MUMPS\_seq Factorize  
– number :0  
– MUMPS solve, peak Mem : 242 Mb, n = 31200 sym =0 trans = 0  
\*\* Instance Error 1 in DMUMPS\_F77 1  
\*\* MPI\_ABORT called.

Attached you have the edp code and the mesh file[Reaction diffusion\_2.edp](https://community.freefem.org/uploads/short-url/oWnmlJdwZXkecajORRIEqz2B0bX.edp) (1.7 KB)  
[Model 1\_2.mesh](https://community.freefem.org/uploads/short-url/8Mb9FfhHCfOSkEegSavFm4sYujs.mesh) (3.3 MB)  
. I hope someone can find the solution of the example

Thank you very much in advance  
Best Regards  
Jacob

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<div class="post-metadata">

**Author:** ![Jacoban90](https://avatars.discourse-cdn.com/v4/letter/j/65b543/32.png) [@Jacoban90](https://community.freefem.org/u/Jacoban90)\
**Post date:** [August 19, 2021, 12:51pm UTC](https://community.freefem.org/t/problem-during-factorization-of-a-system-of-reaction-diffusion-equations/1162/2 "2021-08-19T12:51:21Z")

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Hello again,

I forgot to mention the alpha parameter which is 4.5.

Thank you very much  
Best Regards  
Jacob