``````cvx_begin quiet
variable PEGU(length(y1));
variable PB(length(y1));
variable SOC(length(y1));
variable E(length(y1))
minimize(sum(cf*(pppp(1)*PEGU.^2+pppp(2)*PEGU+pppp(3)).*et)+ce*(SOC(1)-SOC(length(y1)))*Qb*Ueding*nb/1000);
subject to
0.3<=SOC<=0.9;
Pr+Pmloss<=PB+PEGU;
0<=PEGU<=87;
Imin*sqrt(2*E/C*nb)-R*Imin^2*nb<=PB<=E/2/R/C;
E-sqrt(E.^2-2*R*C*E.*PB)<=Imax*R*sqrt(2*C*E*nb);
diff(E)<=-pp(1)/R/Qb*(E-sqrt(E.^2-2*R*C*E.*PB));
C/2*nb*(pp(1)*SOCf+pp(2))^2<=E<=C/2*nb*nb*(pp(1)*SOC0+pp(2))^2;
E(1)==C/2*nb*(pp(1)*SOC0+pp(2));
E(length(y1))==C/2*nb*(pp(1)*SOCf+pp(2));
cvx_end
``````

Error using .* (line 262)
Disciplined convex programming error:
square.

Error in chengxu (line 35)
E-sqrt(E.^2-2RCE.PB)<=ImaxRsqrt(2CE*nb);

What should I do?Thank you.

The error means that the matrix in your quadratic term is not square i.e. has the same number of rows and columns.

1 Like

The variables(such as PEGU,PB,SOC,E)are just vectors and they are related to time(Time is discrete,just like1,2,3,4…).So I want to know how I should show these variables in cvx.Do I should write these variables as PEGU(j),PB(j),SOC(j) and E(j) (j is discrete time) in constraints(subject to)?
Thank you.

The error message description is not as clear as perhaps it could be. This error message is not due to dimensional incompatibility (number of rows and columns), but does indicate a violation of CVX’s DCP rules. In particular, `2*R*C*E.*PB` violates the rule prohibiting multiplication of two different CVX variables or expressions, in this case, `E` and `PB`.

If he constraint `E-sqrt(E.^2-2*R*C*E.*PB)<=Imax*R*sqrt(2*C*E*nb)` is convex, it will need to be reformulated. Have you proven it is convex?

Until you show otherwise, I will mark this problem as non-convex.

Thank you very much.