how define a conditional handle function?

As you know, for

f=@(x) sin(x)/x;

we get f(0)=NaN

if we would like get f(0)=0

again with

f=@(x) (x==0)*0+(x~=0)*sin(x)/x;

we will receive f(0)=NaN.

how can i dominate this problem?

[Adam]

Please try to ensure you format your question in a readable way. The

if true

end

lines should not keep appearing around every bit of code. I don't really know why the '{} Code' button is setup to do this as so many people end up with it included in their code. Also don't include the lines of your question in the middle of one large code block - it is very confusing to read and separate out what is actually code and what is part of the question information.

I did the editing for you this time.

Answer 1

[Torsten]

function main
x = [3 7.5 0 -0.03];
y = f(x)  

function y = f(x)
  i = find(x==0);                                                               
  x(i) = 1;                          
  y = sin(x)./x;                                                      
  y(i) = 0; 
end

Best wishes

Torsten.

[xosro]

Thank you , but i would like use a handle function inside a script, so i can't define another script.

[Jan]

Or a little bit simpler:

function y = f(x)
y       = sin(x) ./ x;
y(x==0) = 0;
end

@xosro: Do not confuse a "handle function" with an "anonymous function", which is accessed by a "function handle".

[Torsten]

My guess is that this function cannot be defined as a "one-liner" as

f=@(x)....

Best wishes

Torsten.

Answer 2

[Jan]

A function (see Torsten's answer) will be nicer and more efficient than an anonymous function. But if you realy have any good reasons:

f = @(x) sin(x) / [Inf(x==0), x(x~=0)];

This works for scalar x only. This would be better, because it is immediately clear, what it does:

function y = f(x)
y       = sin(x) ./ x;
y(x==0) = 0;
end

[xosro]

How can i use

function y = f(x)
y       = sin(x) ./ x;
y(x==0) = 0;
end

inside a code?

[Stephen23]

outval = f(inval)

[Jan]

@xosro: What exactly is your question? Using a function is trivial: as Stephen wrote you use it exactly like you would call an anonymous function also. The only difference is that the function can use multiple commands and has more power. So please explain, what your problem is with using this function, because I do not see any difficulties yet.

[xosro]

well, i have a code that use a function, where this function is undefined on zero point, Because of this i will have a conditional handle function that for zero returns zero and other point returns real value, i can't use another script because there are many variable that are used in the function and when define new script (as Stephen wrote), i receive: Undefined function or variable ' a variable'.

[Jan]

@xosro: The term "conditional handle function" is not defined.

If your function needs many variables, simply define them as inputs or write a "nested function" (search in the documentation for details). If the function is larger, using an anonymous function is even a worse idea, because you cannot exmine it using the debugger.

[xosro]

@Jan Simon: Ok, "nested function" is a good idea, but for using variables as inputs, i had some limitation so i have used "global variables" for using variables between scripts.

Thank you and other dears

[Jan]

Avoid global variables. They cause more troubles than they solve. If you do not want to provide too many arguments, store them in a struct.