Combining multiple functions within one script

2017 2 19
4 个回答
更新时间：2024 5 16
93 次查看（30 天）

1 个投票

I have three functions I would like to put into one script. What would be the correct steps to do so. here are the following functions I have written.
function [] = gravitationalForce(m1,m2,d)
%{m1 = mass 1, m2 = mass 2, d = distance%}
G = 6.672 * 10^11;
syms F
F = (G*m1*m2/(d^2));
display(F)
end
function [] = velocityCalc(u,a,s)
%{u = velocity,a = acceleration,s = distance traveled%}
disp('V^2 =')
v = (u^2 + (2*a*s));
disp(v)
end
function [] = distanceTraveled(u,a,t)
%{u = velocity,a = acceleration,t = time%}
syms s
s = (u*t)+1/2*a*t^2;
display(s)
end

6 个评论
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Brooks Nelson
Brooks Nelson 2017-2-19
编辑：Walter Roberson 2017-2-20
I figured it out. If anyone was wandering I created another function physics with an end after all the full functions were inputed. This allowed me to call the function physics. I then can call each function within the function for an answer. Probably not the best way to do it but it worked for now.
function physics
function [] = gravitationalForce(m1,m2,d)
%{ m1 = mass 1,m2 = mass 2,d = distance%}
G = 6.672 * 10^11;
syms F
F = (G*m1*m2/(d^2));
display(F)
end
function [] = velocityCalc(u,a,s)
%{u = velocity,a = acceleration,s = distance traveled,%}
disp('V^2 =')
v = (u^2 + (2*a*s));
disp(v)
end
function [] = distanceTraveled(u,a,t)
%{u = velocity,a = acceleration,t = time%}
syms s
s = (u*t)+1/2*a*t^2;
display(s)
end
end
Learner
Learner 2020-1-15
looks good but how to call a sub function within physcics function
Walter Roberson
Walter Roberson 2020-1-15
The only ways to call a subfunction that is defined inside another function are:
1. Somehow obtain a handle to the subfunction. For example calling the wrapper function "physics" could return handles to the subfunctions; or
2. Have the wrapper function be a "switchyard" where you pass in information about which subfunction you want to call and the wrapper function calls it on your behalf. For example
function varargout = physics(request, varargin)
switch request
case 'grav'
[varargout{1:nargout}] = GravitationalForce(varargin{:}) ;
end
Invoke with
physics('grav', m1, m2, d)
Kazi Newaz
Kazi Newaz 2022-2-3
编辑：Kazi Newaz 2022-2-3
I get the error Undefined function or variable. What am I doing wrong?
function varargout = addcomp(request, varargin)
function outc=addcomp1(z1,z2)
realpart=real(z1)+real(z2);
imagpart=imag(z1)+imag(z2);
outc=realpart+imagpart*1i;
end
function outc=addcomp2(z1,z2)
outc=z1+z2;
end
switch request
case 'addcomp1'
[varargout{1:nargout}]=addcomp1(varargin{:});
case 'addcomp2'
[varargout{1:nargout}]=addcomp2(varargin{:});
end
end
Walter Roberson
Walter Roberson 2022-2-3
How are you invoking the function, and what is the complete error message?
Kazi Newaz
Kazi Newaz 2022-2-3
extremely sorry to have bothered you, it was an issue with me not having the path set up right, now it is working, thank you so much for the solution

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回答（4 个）

Mohammad Askari
Mohammad Askari 2018-6-30
编辑：Mohammad Askari 2019-11-18

16 个投票

Another approach is to create a class with static methods with all your sub-functions. Save the following code as ALLFUNCS.m
classdef ALLFUNCS
methods(Static)
function result = SumElements(a,b,c)
result = a + b + c;
end
function [prod,div] = MultiplyDivide(v1,v2,v3)
prod = v1 * v2 * v3;
div = v1 / v2 / v3;
end
end
end
Then you can simply call the sub-functions like this:
s = ALLFUNCS.SumElements(3,4,5);
[p,d] = ALLFUNCS.MultiplyDivide(8,3,5);

2 个评论
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leanne dong
leanne dong 2020-4-2
this method does not seem to work for case where a function depends on the previous one.
Any suggestions?
Mohammad Askari
Mohammad Askari 2020-4-3
编辑：Mohammad Askari 2021-10-31
@leanne dong, it actually does. In the example below, the first function calls the other one. Is this what you are looking for?
classdef ALLFUNCS
methods(Static)
function result = SumElements(a,b,c)
result = a + b + c;
string = ALLFUNCS.IsGreaterThanZero(result);
disp(['the answer is greater than zero: ',string]);
end
function str = IsGreaterThanZero(value)
if value > 0
str = 'true';
else
str = 'false';
end
end
end
end

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Anders Bergåker
Anders Bergåker 2017-10-26

5 个投票

Well, I find this limitation incredibly annoying so I use a workaround with the sfunc command. The first function takes the function you actually want to call as an argument. I've found this workaround ages ago, it might have some drawbacks I'm unaware of since I'm not an Matlab expert.
Put all this code in an .m file, eg. myLib.m which then will act as a function library. The call to use a specific function would then be:
myLib('distanceTraveled', u, a, t)
It work fine with returnvalues as well. Examaple of myLib.m:
function varargout = sfunc(varargin)
[varargout{1:nargout}] = feval(varargin{:});
end
function [] = gravitationalForce(m1,m2,d)
...
end
function [] = velocityCalc(u,a,s)
...
end
function [] = distanceTraveled(u,a,t)
...
end

6 个评论
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Rahul Gupta
Rahul Gupta 2018-4-13
If I use this method. do I need to do any configuration for myLib.m file like import or adding path?
Walter Roberson
Walter Roberson 2018-4-21
Like everything for MATLAB it would have to be on your MATLAB path, but you would not need to import
Mohammad Askari
Mohammad Askari 2018-6-30
Nice idea! The only downside is that it creates a false warning ("this function might be unused") for every individual sub-function. Do you have a workaround for this ?
per isakson
per isakson 2020-1-15
"false warning"
Add the line
%#ok<*DEFNU>
to mylib.m
Marcel
Marcel 2024-5-15
Works fantastic and is elegant. Thanks!
Image Analyst
Image Analyst 2024-5-16
You could also comment out the function(s) with %{ and %}.
For example:
%{
function out = MyFunction(in)
out = 2 * in;
end
%}

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Image Analyst
Image Analyst 2017-2-19

1 个投票

You can do that but velocityCalc() and distanceTraveled() would only be available/seen to functions within the same file. If they need to be used by other m-files, you'd have to have them in separate files, unless they were a class. I've done this so I know it works. If you had a class with those functions in it, then any file could call any of those functions as a static method of the class.
John D'Errico
John D'Errico 2017-2-19
编辑：John D'Errico 2017-2-19

0 个投票

If your goal is to use those function independently, then they need to be saved as separate m-files, NOT in one large file. While it would indeed be possible to do that in theory, you would need to learn a fair amount about function handles to do so. As well, you would need to call a main function, then having it return function handles for each sub-function that you might call in the future.
If you are somehow thinking of having an actual script that also has a mainline, but with functions defined within, that is not possible. Scripts cannot also contain function definitions, except for the case of function handles created in one line.
Simple save each function as an independent m-file.

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Image Analyst
Image Analyst 2017-2-19
Starting with R2016b, you can have function(s) below a script all within the same m-file.

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