Hello All,

So i have read other or similar posts about this message and I have read about it online, but I still am not able to make sense of it. I think understand that the error is caused by the fact that taking the sqrt( NEG #) is what is supposed to cause this error, but what i dont understand with my code, is that I have the term squared to correct this. I am a programming newbie so this is probably an easily fixable syntax or input error. Would someone look at my code and tell me what they see?? I have included a picture of the equation i am trying to model.

When I run the code, I receive the following message: FUNC DOMAIN: x**y, x<0. There are no red error messages. Also, Im not exactly sure if I need to sum this for what I am trying to do so If that might be relevant information, there it is.

Also, I am aware that there is information in my code that does not actually get used, I just placed it in there because I am trying to compile everything I think is relevant information. Also, this model is far from being complete, I am just trying to fix one error at a time i guess and slowly build from there.

E2… sum(i,((q1/K)*x)+(Q/4*pi*K)*log((((((x-xw)**2)+(y**2))/(((x+xw)**2)+(y**2))))))=e=phi_2;

Any information or insight that anyone may offer would be greatly appreciated.

Thank you!!

Enter code here…

Set i well /1/;

scalars

K hydraulic conductivity m_d /100/

q1 uniform freshwater discharge /0.6/

d mean ocean SWE /14/

Rs saltwater density /1.025/

Rf freshwater density /1.000/

s saltfreshwater ratio /1.025/

xw well distance from coast line /1000/

y distance between wells /0/

phi_1 saltwater head at tow /2.5/;

positive variable phi_2 freshwater head

Q Optimal pumping rate

x saltwater toe length;

free variable obj objective variable;

equations

E1 constraint on well pumping equation

E2 Equation for the Freshwater potential

E3 toe constraint

E4 objective fcn for max toe length;

E1… phi_1=l=phi_2;

E2… sum(i,((q1/K)*x)+(Q/4*pi*K)*log((((((x-xw)**2)+(y**2))/(((x+xw)**2)+(y**2))))))=e=phi_2;

E3… x=l=xw;

E4… obj=e=x;

model saltwater /all/;

solve saltwater using MINLP maximize obj;

- I dont know what execerror does

execerror=0;

display Q.l, x.l, obj.l;

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