How can i multiply each element of structured array

I am trying to do an optimization problem in matlab.

below is the objective function .Here second and third term Price and Nb_dch1V, Price and Nb_ch1V are struct arrays (1 x 1 struct)

with two fields :

time 288 x 1 double

signal 1 x 1 struct

Signal again has two fields :

values 288 x 241 double

dimensions 241 .

hence is this objective function correct?

I am getting error

An error occurred while running the simulation and the simulation was terminated

Caused by:

• Objective must be a scalar OptimizationExpression or a struct containing a scalar OptimizationExpression.

Please help

prob.Objective =dt*Price'*PbattupsV +dt*Price'*PbattdchV*Nb_dch1V'+ dt*Price'*PbattchV*Nb_ch1V' ;

Answer 1

[Alan Weiss]

You need to extract the correct elements from your structures before using them. I am not sure what you mean to have as an objective. Maybe this:

var1 = dt*Price.time'*PbattupsV; % Check that this is a scalar expression
var2 = dt*Price.time'*PbattdchV*Nb_dch1V.time'; % Check that this is a scalar expression
var3 = dt*Price.time'*PbattchV*Nb_ch1V.time'; % Check that this is a scalar expression
prob.Objective = var1 + var2 + var3;

Alan Weiss

MATLAB mathematical toolbox documentation

[NN]

Thank you very much for the response.

I have tried this , but unfortunately i am getting the below error:

An error occurred while running the simulation and the simulation was terminated

Caused by:

• Dot indexing is not supported for variables of this type.

[NN]

and if i change Price.time to Price , it gives the same errror as before :

An error occurred while running the simulation and the simulation was terminated

Caused by:

• Objective must be a scalar OptimizationExpression or a struct containing a scalar OptimizationExpression.

[NN]

I have tried this way also,

var2 = dt.*Price'.*PbattdchV;

var3 = dt.*Price'.*PbattchV;

prob.Objective =dt.*Price'.*PbattupsV+(var2.*Nb_dch1')+ (var3.*Nb_ch1');

but this gives the error :

An error occurred while running the simulation and the simulation was terminated

Caused by:

Argument dimensions 1-by-241 and 241-by-1 must agree.

Kindly advice

Answer 2

[Alan Weiss]

I'm sorry that you are having these problems, but you must realize that all of them are due to size mismatches in your structures. I am not sure why you are using structures; it might be easier if you simply used matrix variables.

In any case, if you have a 1-by-241 variable and a 241-by-1 variable that you are trying to add, then you should convert both to the same size. There are many ways of converting vectors. If M is the 1-by-241 variable, you can convert it to a 241-by-1 variable in any of the following ways:

M = M(:); % might be the best
M = M';
M = M.';
M = reshape(M,241,1);
M = reshape(M,[],1); % might be the best
M = reshape(M,[241,1]);

Use whichever you like.

Alan Weiss

MATLAB mathematical toolbox documentation

[NN]

thankyou very much, i will try these definetely.

[NN]

unfortunately all the suggested options didnt work, still showing the dimension error

[Alan Weiss]

I suggest that you learn to use the debugger. Set a break point before you create prob.Objective. Carefully examine all your variables. The objective must be a scalar.

Alan Weiss

MATLAB mathematical toolbox documentation

[NN]

sure. will do that.Thank you very much for the support