# "plot of array with wrong number of components (!= 2 or 3) " **URL:** \ **Category:** General Discussion\ **Created:** [January 25, 2023, 11:45am UTC](https://community.freefem.org/t/plot-of-array-with-wrong-number-of-components-2-or-3/2245 "2023-01-25T11:45:39Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![marchywka](https://avatars.discourse-cdn.com/v4/letter/m/ee59a6/32.png) [@marchywka](https://community.freefem.org/u/marchywka)\ **Post date:** [January 25, 2023, 11:45am UTC](https://community.freefem.org/t/plot-of-array-with-wrong-number-of-components-2-or-3/2245/1 "2023-01-25T11:45:40Z")
I keep trying to copy these examples with plot and except for very simple things they end up making errors. I can’t see the difference betwneen my code and the file I copied it from. The excerpt below is from the example Stokes-v3-matrix-mumps.edp with a plot line taken from one of the other examples with variables changed . I’ve seen this error before but no idea what is wrong. Also, I noted that when viewing a plot at the end after solution all the other cores were maxxed out still- gdb showed at least one was in a spin wait loop or similar. You can waste the cores if that is all the thing is doing but in this case I can give up some speed so my browser can run lol. I think this is why I have a bad attitude towards MPI- stepping on each other for memory etc makes a mess very easily. Is there some way to get the other mpiranks to exit while rank zero is showing the plots? Thanks. ````auto //if(mpirank==0) medit("UV2 PV2",Th,[u1,u2,u3],p); if(mpirank==0) plot([u1,u2],p,value=true,coef=.2,wait=1,cmm="[u1,u2] - p "); //plot([Ux, Uy], p, value=true, coef=0.2, cmm="[Ux, Uy] - p"); ```123 : 124 : //if(mpirank==0) medit("UV2 PV2",Th,[u1,u2,u3],p); 125 : if(mpirank==0) plot([u1,u2],p,value=true,coef=.2,wait=1,cmm="[u1,u2] - p ") Error line number 125, in file Stokes-v3-matrix-mumps.edp, before token ) plot of array with wrong number of components (!= 2 or 3) current line = 125 mpirank 0 / 8 Compile error : plot of array with wrong number of components (!= 2 or 3) line number :125, ) error Compile error : plot of array with wrong number of components (!= 2 or 3) line number :125, ) ```` ---
**Author:** ![julienG](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/julieng/32/222_2.png) [@julienG](https://community.freefem.org/u/julienG)\ **Post date:** [January 25, 2023, 4:54pm UTC](https://community.freefem.org/t/plot-of-array-with-wrong-number-of-components-2-or-3/2245/2 "2023-01-25T16:54:38Z")
I think that as it says > [@marchywka](#): > > ` plot([u1,u2],p,...` has wrong dimension. In 2d, `plot([u1,u2],p,...` is correct, but in 3d I think it expects a 3-component array: `plot([u1,u2,u3],p,...` ---
**Author:** ![marchywka](https://avatars.discourse-cdn.com/v4/letter/m/ee59a6/32.png) [@marchywka](https://community.freefem.org/u/marchywka)\ **Post date:** [January 25, 2023, 5:35pm UTC](https://community.freefem.org/t/plot-of-array-with-wrong-number-of-components-2-or-3/2245/3 "2023-01-25T17:35:35Z")
Thanks that seems to work and I never would have guessed that.