How will use return conditions in solve function

Hi,

I didnt get the answer for this solution. I get the message "Solutions are only valid under certain conditions.

To include parameters and conditions in the solution, specify the 'ReturnConditions' value as 'true'."while running the program.

can anyone help to get the solution?

clear all 
clc
p=3200; Av=400;Ab=25;hv=4;hb=5;a=1500;c=5;
syms d1 d0;
for b=10:10:100
      d0=(-8+4*sqrt(2))*(b/a)^2;
      d1=(12-7*sqrt(2))*(b/a);
      x=((a+b*c)-sqrt(2*hb*Ab*a)*d1)/(2*b+2*sqrt(2*Ab*hb*a)*d0)
      Q=sqrt((b*(a-b*c)*Ab+sqrt(2*Ab*hb*a)*Ab*(2*a*d0+b*d1))/(hb*(b+sqrt(2*Ab*hb*a)*d0)))
      syms M
      m1=((a-b*x)*Av*2*p)/(hv*Q^2*(p-a+b*x));
      M=m1;
   for n = 2:1:6
         if n*(n-1)<=M && n*(n+1)>=M;
           x1=n
         end
   end
Pb=((a-b*x)*(x-c))-(((a-b*x)*Ab)/Q)-((hb*Q)/2)
TPv=(a*c)-(b*c*x)-(((a-b*x)*Av)/(x1*Q))-(((hv*Q)/2)*(x1*(1-(a-b*x)/p)-1+(((2*(a-b*x))/p))))
TPi=(a*x)-(b*(x^2))-(((a-b*x)*(Av+n*Ab)/(n*Q))-((hb*Q)/2)-(((hv*Q)/2)*(n*(1-(a-b*x)/p)-1+((2*(a-b*x))/p))));
TPj=0;
nmin=max(ceil(sqrt((Av*(hb-hv))/(Ab*hv))),1);
nmax=ceil(sqrt((Av*p*(hb-hv)+2*Av*hv*a)/(Ab*hv*(p-a))));
n=nmin
         if n>=1
            m1=a/b;
            m2=-1/b;
            m3=2*(Ab+Av/n)*(hb+(n-a)*hv);
            m4=2*hv*(Ab+Av/n)*((2-n)*hv)/p;
syms D
S=(m1+2*m2*D-((m3+2*m4*D)/(2*sqrt(m3*D+m4*D^2))));
solve(S,D);
LO=solve(subs(S),'returnconditions', true);
LO=subs(LO);
LO1=LO(1);
if LO1 < a
  D1=LO1;
else
D1=a;
end 
x=(a-D1)/b
Q= sqrt((b*(a-b*x)*(Ab+Av/n))/(hb+hv*(n*(1-((a-b*x)/p))-1+((2*(a-b*x))/p))))
TPb=((a-b*x)*(x-c))-(((a-b*x)*Ab)/Q)-((hb*Q)/2)
TPv=(a*c)-(b*c*x)-(((a-b*x)*Av)/(n*Q))-(((hv*Q)/2)*(n*(1-(a-b*x)/p))-1+((2*(a-b*x))/p));
TP1=(a*x)-(b*(x^2))-(((a-b*x)*(Av+n*Ab)/(n*Q))-((hb*Q)/2)-(((hv*Q)/2)*(n*(1-(a-b*x)/p)-1+((2*(a-b*x))/p))));
  if TP1>TPj
    TPj=TP1
    TPvj=(TPv/TPi)*TPj
    TPbj=(TPb/TPi)*TPj
    P1=(TPj-TPi)/TPi*100
   else
n=n+1
if n <=nmax
m1=a/b;
m2=-1/b;
m3=2*(Ab+Av/n)*(hb+(n-1)*hv);
m4=2*hv*(Ab+Av/n)*((2-n)*hv)/p;
syms D
S=(m1+2*m2*D-((m3+2*m4*D)/(2*sqrt(m3*D+m4*D^2))));
solve(S,D);
LO=solve(subs(S));
LO=subs(LO);
LO1=LO(1);
if LO1 < a
  D1=LO1;
else
D1=a;
end 
x=(a-D1)/b
Q= sqrt((2*(a-b*x)*(Ab+Av/n))/(hb+hv*(n*(1-((a-b*x)/p))-1+((2*(a-b*x))/p))))
TPb=((a-b*x)*(x-c))-(((a-b*x)*Ab)/Q)-((hb*Q)/2)
TPv=(a*c)-(b*c*x)-(((a-b*x)*Av)/(n*Q))-(((hv*Q)/2)*(n*(1-(a-b*x)/p))-1+((2*(a-b*x))/p));
TP1=(a*x)-(b*(x^2))-(((a-b*x)*(Av+n*Ab)/(n*Q))-((hb*Q)/2)-(((hv*Q)/2)*(n*(1-(a-b*x)/p)-1+((2*(a-b*x))/p))));
if TP1>TPj
TPj=TP1
TPvj=(TPv/TPi)*TPj
TPbj=(TPb/TPi)*TPj
P1=(TPj-TPi)/TPi*100
else
n=n+1
if n <=nmax
m1=a/b;
m2=-1/b;
m3=2*(Ab+Av/n)*(hb+(n-1)*hv);
m4=2*hv*(Ab+Av/n)*((2-n)*hv)/p;
syms D
S=(m1+2*m2*D-((m3+2*m4*D)/(2*sqrt(m3*D+m4*D^2))));
solve(S,D);
LO=solve(subs(S));
LO=subs(LO);
LO1=LO(1);
if LO1 < a
  D1=LO1;
else
D1=a;
end 
x=(a-D1)/b
Q=sqrt((2*(a-b*x)*(Ab+Av/n))/(hb+hv*(n*(1-((a-b*x)/p))-1+((2*(a-b*x))/p))))
TPb=((a-b*x)*(x-c))-(((a-b*x)*Ab)/Q)-((hb*Q)/2);
TPv=(a*c)-(b*c*x)-(((a-b*x)*Av)/(n*Q))-(((hv*Q)/2)*(n*(1-(a-b*x)/p))-1+((2*(a-b*x))/p));
TP1=(a*x)-(b*(x^2))-(((a-b*x)*(Av+n*Ab)/(n*Q))-((hb*Q)/2)-(((hv*Q)/2)*(n*(1-(a-b*x)/p)-1+((2*(a-b*x))/p))));
if TP1>TPj
TPj=TP1
TPvj=(TPv/TPi)*TPj
TPbj=(TPb/TPi)*TPj
P1=(TPj-TPi)/TPi*100
else
n=n+1
end
  end
end
   end
end
end
end

[Rik]

I'm not going to touch barely formatted code that lacks comments. Especially if all variable names are so cryptic the longest one is 3 characters long.

This question also isn't clear to me. What return value should be true? You don't even have a function here.

Have a read here and here. It will greatly improve your chances of getting an answer.

[M]

ok Thank you

[Rik]

Feel free to edit your question to solve these issues.

Answer 1

[Sulaymon Eshkabilov]

(1) You have employed the solve() fcn for a few times and no output variable was assigned. It is better to use this syntax:

[SOL_D, Params, Conds] = solve(S,D,'ReturnConditions',true);

(2) Yoy are assigning a non-numeric value to a new variable and comparing against numerical value 'a':

LO=subs(LO); % Makes no sense here as "LO" defined above
LO1=LO(1);   % Wrong: LO(1) does not exist. LO is a structure variable.  
if LO1 < a   % Wrong: 

[M]

Again, I changed my program as per your instructions, I get this message "Solutions are parameterized by the symbols: z1. To include parameters and conditions in the solution, specify the 'ReturnConditions' value as 'true'." What I do it.