Thread Subject: Fsolve, CAT error : CAT arguments dimensions are not consistent

Hi firends
I want to solve the set of non linear set of equitations as follow :
(I define them in Function Che1) :

function y = Che1(x)
R = 8.314;
T = 1000;
DF_CH4 = 19720;
DF_H2O = -192420;
DF_CO = -200240;
DF_CO2 = -395790;
RT = R*T;
y = [ DF_CH4/RT + log(x(1)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + x(6)/RT +
4*x(8)/RT;
    DF_H2O/RT + log(x(5)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + 2*x(8)/RT + x
(7)/RT;
    DF_CO/RT + log(x(3)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + x(6)/RT + x(7)/
RT;
    DF_CO2/RT + log(x(4)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + x(6)/RT + 2*x
(7)/RT;
    log(x(2)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + x(6)/RT + 2*x(8)/RT;
    x(1) + x(3) + x(4) - 2;
    4*x(1) + 2*x(5) + 2*x(2) -14;
    x(5) + x(3) + 2*x(4) - 3;
    log(x(1)) + log(x(2)) + log(x(3)) + log(x(4)) + log(x(5)) +
3.1011] ;
end
But Matlab Makes an error The errors are as follow :

??? Error using ==> vertcat
CAT arguments dimensions are not consistent.

Error in ==> Che1 at 9
y = [ DF_CH4/RT + log(x(1)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + x(6)/RT +
4*x(8)/RT;

Error in ==> fsolve at 249
            fuser = funfcn{3}(x,varargin{:});

Error in ==> solve_set at 4
y = fsolve(@Che1,x0,option);

Caused by:
    Failure in initial user-supplied objective function evaluation.
FSOLVE cannot
    continue.

Please Help Me
I really need to solve this set of nonlinear equations .

Thanks a lot

I am not sure what is wrong here, but did you try to evaluate your
function Che1 at your x0 point? It seems to me that the error is not an
fsolve problem, it is a function definition problem.

Alan Weiss
MATLAB mathematical toolbox documentation

Ali Modirkhazeni wrote:
> Hi firends
> I want to solve the set of non linear set of equitations as follow :
> (I define them in Function Che1) :
>
> function y = Che1(x)
> R = 8.314;
> T = 1000;
> DF_CH4 = 19720;
> DF_H2O = -192420;
> DF_CO = -200240;
> DF_CO2 = -395790;
> RT = R*T;
> y = [ DF_CH4/RT + log(x(1)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + x(6)/RT +
> 4*x(8)/RT;
> DF_H2O/RT + log(x(5)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + 2*x(8)/RT + x
> (7)/RT;
> DF_CO/RT + log(x(3)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + x(6)/RT + x(7)/
> RT;
> DF_CO2/RT + log(x(4)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + x(6)/RT + 2*x
> (7)/RT;
> log(x(2)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + x(6)/RT + 2*x(8)/RT;
> x(1) + x(3) + x(4) - 2;
> 4*x(1) + 2*x(5) + 2*x(2) -14;
> x(5) + x(3) + 2*x(4) - 3;
> log(x(1)) + log(x(2)) + log(x(3)) + log(x(4)) + log(x(5)) +
> 3.1011] ;
> end
> But Matlab Makes an error The errors are as follow :
>
> ??? Error using ==> vertcat
> CAT arguments dimensions are not consistent.
>
> Error in ==> Che1 at 9
> y = [ DF_CH4/RT + log(x(1)/((x(1)+x(2)+x(3)+x(4)+x(5)))) + x(6)/RT +
> 4*x(8)/RT;
>
> Error in ==> fsolve at 249
> fuser = funfcn{3}(x,varargin{:});
>
> Error in ==> solve_set at 4
> y = fsolve(@Che1,x0,option);
>
> Caused by:
> Failure in initial user-supplied objective function evaluation.
> FSOLVE cannot
> continue.
>
> Please Help Me
> I really need to solve this set of nonlinear equations .
>
> Thanks a lot