Why is matlab unable to perform this script?

Hello,

i have the following script which does a FEM for a room which is imported from GMSH.

Every function works and when i want to run the script, it won't run it. I also tried to clear the workspace but it didnt work as well.

Can anybody help?

It shows in the command window: Unable to perform assignment because the size of

the left side is 1-by-2911 and the size of the

right side is 3347-by-1.

Thank you :)

%Import Raum aus GMSH
m = load_gmsh2('MeshPJ.msh', [1 2]);
P(1,:) = m.POS(:,1); P(2,:) = m.POS(:,2);
T     = m.TRIANGLES(:,1:3); GT  = m.TRIANGLES(:,4);
L     = m.LINES(:,1:2); GL   = m.LINES(:,3);

%Aufbau Gitterstruktur
mesh = buildMesh( T,P,[],GT,L,GL );
clear m T P GT L GL

eps= 2*10^-5*ones(1,mesh.NuDoF);
index = (mesh.P(1,:)<=3.2) & (mesh.P(1,:)>=3) & (mesh.P(2,:)<=4) & (mesh.P(2,:)>=1.5);
eps(index) = 8.75*10^-7;

A = assembDiffusion2D (eps, mesh.T, mesh.P);
f =zeros(1,mesh.NuDoF);
b = assembRightSide2D(mesh, f);

%Randwerte setzen
[ A, b ] = applyDirichletBoundaryConditions(A,b, mesh, 20, @(x,y)323.13);
[ A, b ] = applyDirichletBoundaryConditions(A,b, mesh, 21, @(x,y)283.15);
u=A\b;

%Plotten
trisurf(mesh.T,mesh.P(1,:),mesh.P(2,:),u);
xlabel('x [m]'); ylabel('y [m]');zlabel('T [Kelvin]');
colormap('hot'); clim([260 330]);colorbar;

[Jan]

Please post a copy of the complete error message, which tells the readers, inwhich line the problem occurs.

[Luluhihi2021]

Unable to perform assignment because the size of

the left side is 1-by-2911 and the size of the

right side is 3347-by-1.

Error in PJ2_2 (line 3)

P(1,:) = m.POS(:,1); P(2,:) = m.POS(:,2);

[Benjamin Thompson]

You probably want to at least transpose m.POS before assigning it to P. Then, they are also different lengths. If you are intending to discard the extra values from m.POS, you could do:

P(1,:) = m.POS(:,1:size(P,2))'

Here, the apostrophe character is the MATLAB shorthand for transpose, to turn a column vector into a row vector.

[Walter Roberson]

MATLAB automatically transposes vectors if needed when storing them.

[Luluhihi2021]

Hello,

i tried it and it gave me this error;:

Unrecognized function or variable 'P'.

Error in PJ2_2 (line 4)

P(1,:) = m.POS(:,1:size(P,2))';

Answer 1

[Walter Roberson]

P(1,:) = m.POS(:,1); P(2,:) = m.POS(:,2);

replace that with

P = m.POS(:,[1 2]).';