FZERO requires at least two input arguments

Hey, I need help

function [y,fx,x] = solveNadiabxy(al,bt,ga,kc,yc)
warning off; midtol = 10^-13; 
fzero ltol = 10^-14; mid = 1;   
change if critical options = optimset('dis',[].'tolx', ltol);
x0 = fzero(@Nadiab,0,options,al,bt,ga,kc,yc);
x1 = fzero(@Nadiab,1,options,al,bt,ga,kc,yc);
if abs(x0 - x1) > 10^-10
    check with graph xmid = fzero(@Nadiab,[1.01*x0,0.99*x1], options,al,bt,ga,kc,yc);
else, xmid = (x0+x1)/2; 
end
x = [x0 xmid x1]; 
y = sort ((1+kc*yc + bt*(1-x))/(1+kc));
fx = Nadiab (x,al,bt,ga,kc,yc);
function f = Nadiab(x,al,bt,ga,kc,yc)
f =  1 - x - al*exp(-ga*(1+kc)./(1+kc*yc + bt *(1 - x))) .* x;

this is the code that i used, but everytime want to solve the problem it came Fzero requires arguments

Answer 1

[John D'Errico]

However you got the code you wrote, much of it is not valid syntax in MATLAB.

This line, for example:

fzero ltol = 10^-14; mid = 1;  

That is likely where the error message comes from about input arguments to fzero. For example, if I try to execute that line, I get this error:

fzero ltol = 10^-14; mid = 1;  

Error using fzero (line 133)
FZERO accepts inputs only of data type double. 

Which happens to be what you saw.

As well, several of the lines you have in that code are NOT valid MATLAB syntax. They appear to be comments. Most likely you have mistyped things, and forgotten the % symbols at the beginning of the line. If that was truly exactly what was found in that text, then there is a problem in the text. My guess is that is not the case, but I cannot know.

If you don't recognize MATLAB syntax at all, and are just trying to execute code fragments however you find them, you might want to start by learning at least a little bit about MATLAB. Consider the MATLAB Onramp course.

[Andreas Nathaniel]

THANKS FOR ALL ANSWER :)

Answer 2

[KSSV]

You have to provide inputs to the function. Save those functions in a file, in a folder.

al = give your value ;
bt = give your value ; 
ga = give your value ;
kc = give your value ;
yc = give your value ; 
[y,fx,x] = solveNadiabxy(al,bt,ga,kc,yc) ;

[Andreas Nathaniel]

Sorry, what do you mean in a folder? where can i put the folder?

[Andreas Nathaniel]

After i saved in a file and in a folder, what i need to do next?

[KSSV]

You make that folder as the present working directory.....use cd or run the function, it will ask your permission either to addpath or change the directory.

[Andreas Nathaniel]

Thank you..

[KSSV]

Thanks is accepting the asnwer.. :)

[Andreas Nathaniel]

But, now came another problem , FZERO accepts inputs only of data type double. how to solve this?

[KSSV]

Show me what have you given input variables.

[Andreas Nathaniel]

al = 180000 ;

bt = 1 ;

ga = 15 ;

kc = 1 ;

yc = 1 ;

[y,fx,x] = solveNadiabxy(al,bt,ga,kc,yc) ;

[Andreas Nathaniel]

This code came from the Numerical Techniques for Chemical and Biological Engineers Using MATLAB book

Answer 3

[Steven Lord]

I have a number of pieces of feedback on this code. It looks like it was written for an older version of MATLAB and was copied incorrectly from the textbook.

function [y,fx,x] = solveNadiabxy(al,bt,ga,kc,yc)
warning off; midtol = 10^-13; 

Don't turn off all warnings, especially if you never turn them back on. MATLAB can help you understand where you may be doing something you shouldn't be, but not if you tell it to shut up.

fzero ltol = 10^-14; mid = 1;   

This is almost certainly not what you wanted to write here. This calls fzero with three pieces of text as inputs.

change if critical options = optimset('dis',[].'tolx', ltol);

This attempts to call a function named change with several pieces of text as input. Perhaps the "change if critical" part was supposed to be a comment and the optimset call was supposed to be on the next line, like this?

% This section added by Steve Lord, not part of the original code

% change if critical
options = optimset('dis', [], 'tolx', ltol);

x0 = fzero(@Nadiab,0,options,al,bt,ga,kc,yc);
x1 = fzero(@Nadiab,1,options,al,bt,ga,kc,yc);

While this works, it's an older syntax for fzero. That syntax is supported for backwards compatibility and is no longer documented. Instead you should use one of the techniques given on this documentation page to pass the additional parameters into your Nadiab function.

if abs(x0 - x1) > 10^-10
    check with graph xmid = fzero(@Nadiab,[1.01*x0,0.99*x1], options,al,bt,ga,kc,yc);

This tries to call a function named check with several pieces of text as input. Like the "change if critical" section, it looks like the first part is supposed to be a comment. It also uses the older fzero syntax.

[Andreas Nathaniel]

can i get the newest one and the correct one?

[Steven Lord]

The newest what? The newer syntax for fzero? See that documentation page I linked for some of the currently recommended ways to pass additional parameters into the function you pass into fzero.