Comsol multiphysics; fzero and inline function with many parameters

[hadoque]

Hi
I'm trying to get comsol multiphysics to first define an inline
function with 1 variable and 4 parameters, and then run fzero on that
same function. I can do it with two parameters, but no moore.

This works:

clear
myfun=inline('exp(y).*cos(x)+z', 'x', 'y', 'z');
x1 = fzero(myfun,-5,2,1)

This does not work:

clear
myfun=inline('exp(y).*cos(x)+z+u', 'x', 'y', 'z', 'u');
x1 = fzero(myfun,-5,2,1,0.3)

C» test
Error: Too few arguments to inline function.

Would be thankful for any hints about this.


/Johan

 

[Greg Bernhardt]

Hi Johan,
I had a similar issue when trying to use the fzero function in COMSOL Multiphysics. It seems that you need to pass the additional parameter as an anonymous function. Try this:

clear
myfun=inline('exp(y).*cos(x)+z+u', 'x', 'y', 'z', 'u');
x1 = fzero(@(x) myfun(x,-5,2,1,0.3),-5)

Hope this helps!

 

[oswaler]

Hello Johan,

It seems like you are trying to use the fzero function on an inline function with multiple parameters. This may not work because the fzero function is designed to find zeros for a single variable function, not a function with multiple variables.

One solution could be to define a new function that combines all the parameters into a single variable, and then use that function with the fzero function. For example:

myfun2 = @(x) myfun(x,2,1,0.3); % combining the parameters into a single variable
x1 = fzero(myfun2,-5);

Another option could be to use the fsolve function, which allows for multiple variables and parameters.

I hope this helps! Good luck with your research.