# Compilation Error with Raviart-Thomas (RT) element

**URL:** <https://community.freefem.org/t/compilation-error-with-raviart-thomas-rt-element/282>\
**Category:** FreeFEM installation\
**Created:** [March 1, 2020, 8:12pm UTC](https://community.freefem.org/t/compilation-error-with-raviart-thomas-rt-element/282 "2020-03-01T20:12:02Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Hanen](https://avatars.discourse-cdn.com/v4/letter/h/5f8ce5/32.png) [@Hanen](https://community.freefem.org/u/Hanen)\
**Post date:** [March 1, 2020, 8:12pm UTC](https://community.freefem.org/t/compilation-error-with-raviart-thomas-rt-element/282/1 "2020-03-01T20:12:02Z")

</div>

Hello Evry one ,  
I need you help, i got such errors when compiling my code:

“Compile error : Invalide array size for vectorial fespace function”,  
I changed the finite element , i just moved from P1 ( with P1 finite element the code is working fine) to RT0Ortho.

fespace ESh(Sh, RT0Ortho);  
fespace ETh(Th, RT0Ortho);

ETh u1, u2, u3,u4, u5, u6, w1, w2, w3,w4, w5, w6;  
ETh us1, us2, us3, us4, us5, us6;  
ETh uss1, uss2, uss3, uss4, uss5, uss6;  
ETh u21, u22, u23, u24, u25, u26;  
ETh u11, u12, u13, u14, u15, u16;  
ETh w21, w22, w23, w24, w25, w26;  
ETh v1, v2, v3,v4, v5, v6;

Any ideas ?  
Thanks,  
Hanen

---

<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:** [March 1, 2020, 8:43pm UTC](https://community.freefem.org/t/compilation-error-with-raviart-thomas-rt-element/282/2 "2020-03-01T20:43:28Z")

</div>

Raviart–Thomas FE are vectorial FE.

```auto
ETh u1, u2;

```

should read:

```auto
ETh [u1, u2];

```

---

<div class="post-metadata">

**Author:** ![Hanen](https://avatars.discourse-cdn.com/v4/letter/h/5f8ce5/32.png) [@Hanen](https://community.freefem.org/u/Hanen)\
**Post date:** [March 2, 2020, 4:02pm UTC](https://community.freefem.org/t/compilation-error-with-raviart-thomas-rt-element/282/3 "2020-03-02T16:02:45Z")

</div>

Thanks #prj for the answer,

Yes, i do that in the code, but i get a compile error

Compile error : interpolation of no scalar FE function component with scalar function

A little script that illustrates my problem follows  
when i make like this  
ETh [u1, u2];  
ETh [u3, u4];  
ETh [u5, u6];  
ETh [w1, w2];  
ETh [w3, w4];  
ETh [w5, w6];  
ETh [us1, us2];  
ETh [us3, us4];  
ETh [us5, us6];

ETh[uss1, uss2];  
ETh[uss3, uss4];  
ETh[uss5, uss6];

Thanks.