why do I get error for Undefining function sdpvar and how can I solve it?

I got an error saying:

Undefined function 'sdpvar' for input arguments of type 'double'.

Error in Untitled3 (line 1)

A=sdpvar(3,1); Tc=sdpvar(2,1); Tout=sdpvar(3,1); gam=1e5;

for the following code:

[Geoff Hayes]

@Meme alcute - what is returned when you try

which -all sdpvar

from the command line? Please copy and paste the results to this question.

[KSSV]

spdvar is not an inbuilt function. It is user defined function. We cannot help you unless the function is attached here.

[Meme alcute]

Here is the problem And here is the answer I got from Solving Optimization Problems with MATLAB book. However, when I use exactly the same code I get an error as stated above.

[Meme alcute]

This is the code:

A=sdpvar(3,1); Tc=sdpvar(2,1); Tout=sdpvar(3,1); gam=1e5;

U=[120,80,40]; Tcin=100; T1in=300; T2in=400;

T3in=600; Tcout=500;

cons=[Tc(1)+Tout(1)-Tcin-T1in<=0,

-Tc(1)+Tc(2)+Tout(2)-T1in<=0,

Tout(3)-Tc(2)-T3in+Tcout<=0,

A(1)-A(1)*Tout(1)+gam*Tc(1)/U(1)-gam*Tcin/U(1)<=0,

A(2)*Tc(1)-A(2)*Tout(2)-gam*Tc(1)/U(2)+gam*Tc(2)/U(2)<=0,

A(3)*Tc(2)-A(3)*Tout(3)-gam*Tc(2)/U(3)+gam*Tcout/U(3)<=0,

100<=A(1)<=10000, 1000<=A([2,3])<=10000,

10<=Tc<=1000, 10<=Tout<=1000];

opt=sum(A);

optimize(cons,opt), value(A), value(Tc), value(Tout)

and here is the error:

Answer 1

[Cris LaPierre]

You have not installed YALMIP Toolbox. Once you do, you will have access to sdpvar.

This is not a MathWorks supplied toolbox, so you will need to follow the intructions given to you to install and use this toolbox.

[Meme alcute]

Hoe to download YALMIP Toolbox?

[Cris LaPierre]

Not sure, as it's not a MathWorks product, but I think exploring the Download menu on the page I linked to would be a good place to start.

[Steven Lord]

Click the Download link on the page to which Cris linked and follow the instructions on that page.

[Meme alcute]

I could not find the link, where is it?

[Muhammad Yasir]

sdpvar is used to define YALMIPs symbolic decision variables.

It is keyword/function of YALMIP. It's not a standard MATLAB operator or keyword.

Have you set path to YALMIP forlder from MATLAB?

Seems like your MATLAB is not recognizing YALMIP supported functions.