In Matlab, a function handle is a mechanism provided to allow for indirect calling of a function. Serves like a "pointer to function"
A function handle is a matlab value that provides a means of calling a function indirectly.
Questions tagged [function-handle]
159 questions
38
votes
3 answers
What is a function handle and how is it useful?
Can somebody explain to me the meaning of the @ (function handle) operator and why to use it?
Dikla
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13
votes
3 answers
What is the @ operator (at sign) in MATLAB?
I have some MATLAB programs that use the @ (at sign) as an operator. What does it mean?
Does MATLAB 6.5 support this operator?
Yin Zhu
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11
votes
2 answers
Matlab: defining a function handle catching second returned value of a function
Say that I have a function foo defined as
[a b] = foo(c ).
If I consider a function handle
f = @(c)foo(c)
to be used e.g. in a cellfun call, what I get is an f behaving equivalently to a foo defined like
a = foo(c)
i.e., the returned…
Acorbe
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10
votes
1 answer
Creating a function handle to an overloaded `end` function
MATLAB allows overloading various operators for custom classes. One of the unlisted overloadable operators is end, as can be learned from \matlab\lang\end.m:
% END(A,K,N) is called for indexing expressions involving the object A
% when END is…
Dev-iL
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10
votes
1 answer
MATLAB- passing a function handle parameter into another function as a handle
Working on an assignment involving Genetic Algorithms (loads of headaches, loads of fun). I need to be able to test differing crossover methods and differing mutation methods, to compare their results (part of the paper I have to write for the…
user194638
9
votes
3 answers
Matlab mex-file with mexCallMATLAB is almost 300 times slower than the corresponding m-file
I started implementing a few m-files in C++ in order to reduce run times. The m-files produce n-dimensional points and evaluate function values at these points. The functions are user-defined and they are passed to m-files and mex-files as function…
Meteor
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9
votes
1 answer
How can I create function pointers from a string input in MATLAB?
If I use the inline function in MATLAB I can create a single function name that could respond differently depending on previous choices:
if (someCondition)
p = inline('a - b','a','b');
else
p = inline('a + b','a','b');
end
c = p(1,2);
d =…
JP.
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8
votes
1 answer
Matlab - Check if function handle is a particular function or function type
Question: In Matlab, how can I check if a function handle is a particular function or function type?
Example: Let f1 be a function handle. How do I check if f1 is the in-built Matlab function mean? How do I check if f1 is an anonymous function?
My…
Colin T Bowers
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7
votes
3 answers
When can I pass a function handle?
I have a function for cached evaluation. As one of the arguments, it takes a function handle. Under some circumstances, the function handle is unaccessible, and I don't quite understand why. The example below shows what got me stumped:
>> A.a =…
gerrit
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6
votes
4 answers
Get the derivative of a function_handle in MATLAB
Is it possible to get the derivative of a function_handle as a other function_handle?
Like:
fun1 = @(x) x^2;
% do that ...
disp(fun2);
@(x) x*2
I know how to find the derivative of a symbolic function but I can't convert a function_handle…
user839791
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6
votes
2 answers
Conditional element replacement using cellfun
vec = randi(10,10,1)
vec(vec < 5) = 0
func = @(x) x(x < 5) = 0 % This isn't valid
How am I supposed to translate the second line of code into a function handle that I can use in conjunction with cellfun?
Andi
- 3,196
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6
votes
2 answers
How to write an anonymous function with a variable number of output arguments?
Using deal we can write anonymous functions that have multiple output arguments, like for example
minmax = @(x)deal(min(x),max(x));
[u,v] = minmax([1,2,3,4]); % outputs u = 1, v = 4
But if you want to provide a function with its gradient to the…
flawr
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6
votes
5 answers
Calling matlab callback/function handle from Java
How do I pass a matlab function handle to a Java object and invoke it from within Java (that is, I want Java to tell matlab when it is ready with a calculation). I am trying to use the com.mathworks.jmi.Matlab class for evaluating Matlab expressions…
jakob
5
votes
1 answer
Why are predefined variables not shown with their value in function handles?
In MATLAB R2020b I have the following code:
f=@(x) x.^2;
y=2;
g=@(x) f(x).*y
and the output is
g = function_handle with value: @(x)f(x).*y
But y = 2, so I would expect the output to be @(x)f.*2. Is this how its supposed to work or a bug? And can I…
Matt Majic
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5
votes
1 answer
Is it possible to test a function handle without try block?
Is is possible to replace the following code with something which does not use exceptions? The handle x is a provided handle. I want to test it for validity (having actual code to back the handle) before use.
x = @notreallyafunction;
try
…
Andrej Mikulik
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- 14