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
2
votes
1 answer
Derivative of anonymous functions without defining symbolic variables in Matlab
Consider the following code:
f = @(x) x.^2;
Is it possible to get the derivative of the function handle f as another function handle, without defining a symbolic variable?
Msh
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2
votes
1 answer
Matlab parsing at run-time of function handles
My Question: Given a function handle, does matlab parse the string each time it needs to evaluate it, or just once and then it caches it?
Example
Consider the ingenious function
function [] = foo(func)
for j=1:1e4
func(j);
end
and the…
Amir Sagiv
- 376
- 5
- 23
2
votes
1 answer
Get the handle of a function of a class that has no instantiation yet
I am fairly new to C#.
What I want to do may seem convoluted.
Let's start by saying that I want to take a handle of some functions in order to execute them later on. I know that I can achieve this in the following way:
List list = new…
Vaaal88
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- 25
2
votes
2 answers
How to access function handles in a cell array?
rate_arr_cst_1 = @(t) 2*sin(t)+10;
rate_arr_cst_2 = @(t) 3*sin(2*t)+8;
rate_arr_cst_h = {rate_arr_cst_1, rate_arr_cst_2};
I defined a cell array in such way and try to access in the following way:
i=1;
h = rate_arr_cst_h(i);
but what I get here…
Loading Zone
- 177
- 2
- 12
2
votes
1 answer
fminsearch error: DOUBLE cannot convert the input expression into a double array
I am encountering a problem during an optimization exercise. I am trying to use fminsearch() in matlab to solve it. The following error is generated when the code is run:
The following error occurred converting from sym to double: Error
using…
pvl
- 194
- 1
- 10
2
votes
1 answer
Function Handles in Julia
What is the standard way to define a callback function, or a function handle in Julia?
Suppose I define
function myFun(a, b, c, d)
a - 3* b - c * d # The return value
end
My goal is to fix b = 1, c = 2, d = 3, and pass myFun as a function of…
user25004
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2
votes
2 answers
How to create an array of functions in matlab?
I was trying to solve Lorenz System in matlab by using the method of RK2 and RK4. I had a script for both of the methods, the problem now is how can converge the following
y(1) = @(t,y) 10*(y(2)-y(1));
y(2) = @(t,y) y(1)*(28-y(3))-y(2);
y(3) =…
Lechen Yuan
- 23
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2
votes
1 answer
Trouble with anonymous functions in matlab
I am having trouble with printing out h_a_b. I am able to get functions f and g but not this one. I need to use h_a_b function so i can do h(f(x),g(x)) and calculate the sqrt of h(a,b). see equations
I am always getting this error
Undefined function…
user2353565
- 47
- 9
2
votes
2 answers
Errors when using functions with multiple inputs
I am trying to evaluate a duffing oscillator in MATLAB with multiple inputs, and I am getting an odd error I was hoping someone might be able to help me with.
Here is the code:
% file duffing.m
function dy=duffing(t,y,a,b,d,g,w)
dy=[y(2);…
user188764
- 23
- 3
2
votes
2 answers
`localfunctions` inside a package
localfunctions returns function handles to all the local functions in an m-file. However, this doesn't work in a package. For example, the following code saved as 'a.m' runs fine:
function fs = a()
fs = localfunctions;
end
function…
Memming
- 1,731
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2
votes
2 answers
MATLAB optimization: speed up computation on large matrices
I am using the following function:
kernel = @(X,Y,sigma) exp((-pdist2(X,Y,'euclidean').^2)./(2*sigma^2));
to compute a series of kernels, in the following way:
K = [(1:size(featureVectors,1))', kernel(featureVectors,featureVectors,…
Eleanore
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2
votes
3 answers
how can I pass an argument to a function handle, but interpret it only on call time?
What I want to do is:
a = 5
foo = @(x) x+a
a = 3
foo(1) % recieve 4
Instead, I only get 6! On several other tests I ran, I get that a is evaluated when foo is, and and not when foo is called.
For various reasons, I can't work with
foo = @(x,a)…
Amir Sagiv
- 376
- 5
- 23
2
votes
1 answer
MATLAB: Function Handle of Nested Function
Is there a way to create a function handle to a nested function that includes the parent function in the function handle?
As an example, say I have:
function myP = myParent()
myP.My_Method = myMethod;
function myMethod()
disp…
Jomnipotent17
- 451
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2
votes
2 answers
nargin on matlab class method returns -1
I have the following scenario. In myClass.m I have defined
classdef myClass
...
methods
function y = foo(this, x)
...
end
end
end
Then I execute
obj = myClass();
nargin(@obj.foo)
and get as a result -1 while…
kon psych
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2
votes
1 answer
Cell Array and function handle
Look at the below code:
for i=1:2
if i == 1
F{i}= @(x) x(i)+x(i+1);
else
F{i}= @(x) x(i-1)-x(i)+2;
end
end
I wanted to have stored in F something like F={@(x) x(1)+x(2);@(x) x(1)-x(2)+2;}. How should I edit my code to achieve this? Can…
user2745742
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