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From: Anna Zabai on 19 May 2010 10:40
I am using Matlab 7.6.0.324, and I find that I am having problems using fsolve to solve a system on two non-linear equations in two unknowns. I am relatively new to Matlab, so I apologise in advance if I seem inexperienced. I am.
Basically when I call my M-file myfun.m within the main command window i.e. when I type

x = fsolve(myfun,x0)

I get an error message which says ??? Undefined function or variable 'myfun'.
even though the function is saved in my current directory.

I am not sure what I am doing wrong. I am attaching a copy of the myfun.m file.

Thank you very much for your advice

Anna

function F = myfun(x)

F = [(1+x(1)*(x(2)^2)*(1-h*cdf('Normal',sqrt(rho*k)*(h*x(2)*x(1)*(g2-(1-h/2)*x(2)*x(1))-z),0,1)))*x(1) - g1 + x(1)*x(2)*g2*(1-h*cdf('Normal',sqrt(rho*k)*(h*x(2)*x(1)*(g2-(1-h/2)*x(2)*x(1))-z),0,1)) + x(1)*sqrt(rho*k)*h*x(2)*x(1)*(g2-(1-h/2)*x(2)*x(1))*h*x(2)*(g2-(2-h)*x(2)*x(1))*pdf('Normal',sqrt(rho*k)*(h*x(2)*x(1)*(g2-(1-h/2)*x(2)*x(1))-z),0,1);
h*x(2)*x(1)*(g2-(1-h/2)*x(2)*x(1) - z - sqrt(rho*(1+k))*icdf('Normal',(1-1/(x(1)*x(2)))/h,0,1) + (1+k)*sqrt(rho)*icdf('Normal',x(1)/w,0,1)];
From: Nicholas Kinar on 19 May 2010 12:08
On 10-05-19 8:40 AM, Anna Zabai wrote:
> I am using Matlab 7.6.0.324, and I find that I am having problems using
> fsolve to solve a system on two non-linear equations in two unknowns. I
> am relatively new to Matlab, so I apologise in advance if I seem
> inexperienced. I am. Basically when I call my M-file myfun.m within the
> main command window i.e. when I type
>
> x = fsolve(myfun,x0)
>
> I get an error message which says ??? Undefined function or variable
> 'myfun'.
> even though the function is saved in my current directory.
> I am not sure what I am doing wrong. I am attaching a copy of the
> myfun.m file.
> Thank you very much for your advice
>
> Anna
> function F = myfun(x)
>
> F =
> [(1+x(1)*(x(2)^2)*(1-h*cdf('Normal',sqrt(rho*k)*(h*x(2)*x(1)*(g2-(1-h/2)*x(2)*x(1))-z),0,1)))*x(1)
> - g1 +
> x(1)*x(2)*g2*(1-h*cdf('Normal',sqrt(rho*k)*(h*x(2)*x(1)*(g2-(1-h/2)*x(2)*x(1))-z),0,1))
> +
> x(1)*sqrt(rho*k)*h*x(2)*x(1)*(g2-(1-h/2)*x(2)*x(1))*h*x(2)*(g2-(2-h)*x(2)*x(1))*pdf('Normal',sqrt(rho*k)*(h*x(2)*x(1)*(g2-(1-h/2)*x(2)*x(1))-z),0,1);
>
> h*x(2)*x(1)*(g2-(1-h/2)*x(2)*x(1) - z -
> sqrt(rho*(1+k))*icdf('Normal',(1-1/(x(1)*x(2)))/h,0,1) +
> (1+k)*sqrt(rho)*icdf('Normal',x(1)/w,0,1)];

Anna:

Try using the following call to fsolve:

x = fsolve( @myfun,x0 );

Note that you must also define {rho, k,...} and all of the other
variables in your function. See the help file for fsolve and the
section "Passing further parameters" for more information.

Nicholas
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