Dot indexing is not supported for variables of this type.

please someone help me with this as soon as possible as i have a submission due.

I am new to Matlab,and i dont know why this error pops up in mycod.This code is same to all other students and they are able to run it and i am not.

1)L2_1D_P3 file (which i run )

clear;format long;
%Computational domain
Lx=1;
%Local variables
XSeed= 11;
%Diffusity function
diffusivity_function=struct('type','scalar','d',1.0);


%Volumeteric Source
load_type=struct('case','homogeneous','value',1.0);

%Standard data
dim=1;dofs_per_node=1;
EleType='L2';
NGPTS=3;

%Nele and NumNodes
Nele= XSeed-1;
NumNodes=XSeed;

%Coordinate matrix
Coord=zeros(NumNodes,dim);
for row =1:XSeed
    Coord(row)=Lx*(row-1)/(XSeed-1);
end

%Connectivity matrix
Connectivity=zeros(Nele,2);
for ele = 1:Nele
    Connectivity(ele,:)=[ele,ele+1];
end
%Constraints matrix
Constraints=[1,1,0];

NCons= size(Constraints,1);

%Call the driver to run simulation
[U] = Driver_Steady_Diffusion(Connectivity,Constraints,...
Coord,dim,dofs_per_node,diffusivity_function,EleType,load_type,NCons,...
Nele,NGPTS,NumNodes);

%Colorful plots
plot(Coord,U,'k*','MarkerSize',20);hold on;
plot(Coord,Coord.*(Lx-Coord/2),'b-','LineWidth',2);
Legend('Numerical','Analytical','FontSize',20);
xlabel('x','FontSize',20);
ylabel('c(x)','FontSize',20);

2) Get_Volumetric source(where the error is)

function [f]=  Get_VolumetricSource(load_type,x)



if strcmpi(load_type.case,'homogeneous')
    f=load_type.value;
    return;
end

my error message: when i run for L2_1D_P3 file

L2_1D_P3

__________________________________________

Diffusion Simulation Status Report

__________________________________________

Step1:Create GlobalId Vector

Step2:Create constraints vector

Step3: Calculate global stiffness matrix and load vector;

Dot indexing is not supported for variables of this type.

Error in Get_VolumetricSource (line 5)

if strcmpi(load_type.case,'homogeneous')

Error in CalculateLocalMatrices (line 34)

rlocal=rlocal+w(gpt)*N'*Get_VolumetricSource(load_type,x)*detJ;

Error in CalculateGlobalMatrices (line 30)

[klocal,rlocal]=CalculateLocalMatrices(diffusivity_function,EleNodes,EleType,...

Error in Driver_Steady_Diffusion (line 36)

[K_FF,K_FP,R_F]=CalculateGlobalMatrices(Connectivity,...

Error in L2_1D_P3 (line 39)

[U] = Driver_Steady_Diffusion(Connectivity,Constraints,...

[Rik]

How is the Get_VolumetricSource function called? What are the input arguments?

[Kiran Patil]

this is the input

%Volumeteric Source

load_type=struct('case','homogeneous','value',1.0);

[Kiran Patil]

My files , can someone just copy all the files in a folder and try running L2_1D_P3.m file and debug it for me.

[Rik]

Apparently not. What is the exact syntax you are using to call Get_VolumetricSource?

________
_____=Get_VolumetricSource(_______)

[Rik]

You really need to learn debugging. Put a breakpoint on the first line of L2_1D_P1, run it and then run your code step by step. Then you can step in and out of functions to explore where your variables don't match your expectations anymore.

I doubt someone will go to trouble of downloading dozens of files. Try to make a MWE so we can run your code without any other dependencies and can reproduce your issue.

[Kiran Patil]

this is where i want the Get_VolumetricSource(load_type,x)*detJ

rlocal=rlocal+w(gpt)*N'*Get_VolumetricSource(load_type,x)*detJ;

[Kiran Patil]

sorry , but i am very new to any type of coding laguage.can you send me any links or source like youtube where i can know how to debug line by line as you said,

[Kiran Patil]

1) this is a function

function [f]=  Get_VolumetricSource(load_type,x)



if strcmpi(load_type.case,'homogeneous')
    f=load_type.value;
    print load_type.case
    return;
end

2) this is input ( where i tell what is load_type ( case and its value)

load_type= struct('case','homogeneous','value',0.0);

3)this is where i want it to give me the f output

f= Get_VolumetricSource(load_type,x);
    

4)i am using this f for further multiplication with other variables .

rlocal=rlocal+w(gpt)*N'*f*detJ;

Answer 1

[Guillaume]

What the error message is telling you is that in Get_VolumetricSource at the point you do:

if strcmpi(load_type.case,'homogeneous')

load_type is not a structure (or something else that supports dot indexing).

Indeed, you created load_type as a structure in your script, so there's a problem in between where it gets replaced by something else and you need to find where. The error message also gives you the call stack, it's going through Driver_Steady_Diffusion, then CalculateGlobalMatrices, then CalculateLocalMatrices, and finally . Note that it may have a different name in each function.

As Rik said, you need to debug your code. Follow the process detailed in the documentation, put a breakpoint at the start of your script and step through the code line by line, observing the state of each variable as they change, in particular that load_type variable and see where its content get replaced by something else. You could also first set a breakpoint at the start of Get_VolumetricSource and see what is actually in load_type when it gets called.

edit:

In Driver_Steady_Diffusion, you have:

[K_FF,K_FP,R_F]=CalculateGlobalMatrices(Connectivity,...
    Coord,diffusivity_function,dim,dofs_per_node,EleType,load_type,GlobalID,...
    NCons,Nele,NEqns,NGPTS);

load_type is the 7th argument passed to CalculateGlobalMatrices

The signature of CalculateGlobalMatrices is:

function [K_FF,K_FP,R_F]=CalculateGlobalMatrices(Connectivity,...
    Coord,diffusivity_function,dim,dofs_per_node,EleType,GlobalID,load_type,...
    NCons,Nele,NEqns,NGPTS)

where load_type is the 8th argument. So there's your problem, load_type and GlobalID get swapped. Note that in matlab (and the majority of other programming languages), the name of the arguments is not important, it's their position that is critical.

[Kiran Patil]

thank you , very much , it now doesnt show the error and i understood who this coding thing works