i want to change function variable at each step in a for loop in matlab.
i take these steps:
i created my mfile function
function [jfun,fun]=air(x,vt,ty,tz,p2,y0)
jfun=[(cos(tz)*cos(ty)*vt/9.81)*(1-exp(-9.81*x(2)/vt)),...
x(1)*cos(tz)*cos(ty)*exp(-9.81*x(1)/vt);
(-vt*sin(tz)*cos(ty)/9.81)*exp(-9.81*x(1)/vt),...
(x(1)*sin(tz)*cos(ty)*+vt)*exp(-9.81*x(1)/vt)];
fun=[(x(1)*cos(ty)*cos(tz)*vt/9.81)*(1-exp(-9.81*x(2)/vt))-p2;...
(vt/9.81)*(x(1)*sin(tz)*cos(ty)+vt)*(1-exp(-9.81*x(2)/vt))-vt*x(2)+y0];
end
and then i used newtonSys command:
ty=rad(-23)
tz=rad(15)
p2=1.8
vt=8.4925
y0=0.2
myfun=#(x)air(x,vt,ty,tz,p2,y0)
x=newtonSys(myfun,[15 5],0.000001,0.000001,500,1)
and matlab answer:
Error in ==> Untitled18 at 7
x=newtonSys(myfun,[15 5],0.000001,0.000001,500,1)
i guess that its because of wrong use of function handle and for my function i have to use another command or i have to use another method for solving 2nonlinear equation.
First, you haven't displayed the entire error. MATLAB should tell you what the actual error is, so unless you tell us that, we won't know what's wrong.
Secondly I don't see newtonSys in my system, or in the online MATLAB documentation. So most likely it is an external program, which most people here might not be familiar with. The closest I found from a quick Google search was this, which is an implementation of Newton's method for approximating the root of a non-linear system of n-equations. Are you using the same file? If so, if you look at the comments, it says that you need to pass the function as a string. So you'd have to pass myfun as 'myfun'.
If not, could you edit your question and add the contents of the function that you're using? Without these, it's near impossible to answer your question.
Related
I'm trying to use for example setoutdist Matlab function from the MPC Toolbox (I'm using Matlab R2013a on Windows 8.1). As a response I'm receiving:
Undefined function 'setoutdist' for input arguments of type 'ss'.
I am able to get help about this function using help setoutdist. When I'm typing the function name and left parenthesis I'm receiving prompt with list of the arguments. When I'm using which setoutdist -all I'm receiving proper output:
C:\Program Files\MATLAB\R2013a\toolbox\mpc\mpc\#mpc\setoutdist.m % mpc method code here
But the function doesn't work even in default Matlab path, so I don't think it is shadowed.
The same is with the other functions, for example setindist, setestim, mpc_struct, etc. but mpc, mpcstate and mpcmove functions works correctly.
I was trying: clear all, clear classess, rehash toolbox, rehash pathreset, rehash toolboxreset, restoring default paths using pathtool. I've blocked the antivirus and added exeptions to it's list. I've even reinstalled my Matlab, nothing helped.
Maybe this is significant: when I'm trying to edit the setoutdist.m I'm receiving message that access is denied.
I will extremly appreciate any help...
How are you calling setoutdist? The correct syntax is one of the three (see documentation - for R2014b):
setoutdist(MPCobj,'integrators')
setoutdist(MPCobj,'remove',channels)
setoutdist(MPCobj,'model',model)
where MPCobj is a Model Predictive Controller object, created for example with the mpc function. It looks like from the error message that you are calling the function with a state-space object, which is not allowed (I'm guessing).
I am now using Matlab GUI and have problem during accessing return values from a function which is set by set().
Situation:
I set the windowMotionFcn as below:
set(gcf,'WindowButtonMotionFcn',#test);
Function 'test' can return 2 variables (named as var1 and var2).But I dont know how to store them...
I have searched in the Internet and could not find any way.
How should I write?
Thank you for your help and kind attention.
I think that what you want to do is to return a value from the callback function. And regarding returning a value from a callback I am not sure that is possible. I found an old article from matlab newsreader. I think your problem could be similar.
However, if you have a matlab GUIDE GUI, there is a way to return a value from a gui. It is described in a matlab tutorial in matlab central: advanced-getting-an-output-from-a-guide-gui. What you must do is to modify your CloseRequestFcn and your OutputFcn.
Another way, which should work is using global variables. A global varable exist in the global workspace. That means that it can be seen and accessed by every function in matlab. Global variables are in most cases not recommended, but if no other solution exists they may be necessary. Just make sure to document them, so that the next person to take over your code knows that they are there. Also make sure to select a good name for the globals, like gblMyVar so there can be no confusion that the variable is global.
Somehow my Matlab does not has the function nanvar_base, needed to use the function ttest2 to calculate the t and p value of two sample data. How do I install that function? Is it missing to anyone else?
I had this same issue, the ttest2 function calling a nanvar function from SPM rather than the MATLAB statistics folder. A simple fix is going into 'change paths' in MATLAB and moving the SPM paths to the bottom of the list.
The function ttest2 is part of the statistics toolbox.
However, when I try to edit it, it does not show any calls to nanvar_base.
Did you perhaps try to edit it yourself, and in the process made a mistake? If this is not the case, try edit ttest2 and see where it is located and show the line with the call to nanvar_base.
This function isn't part of MATLAB or any of its toolboxes/add-ons. It must be custom functions. There is a function call nanvar however, in the Statistics toolbox and also in the Financial toolbox. Is this maybe the one you're after? If so, do you actually have the Statistics Toolbox and/or the Financial Toolbox?
the problem is probably another toolbox (like SPM) getting in the way, with their own 'nanvar' function.
Move SPM to the bottom of the path definition list, or remove it completely.
In general moving SPM have a lot of conflicting functions, so always make sure their path is at the bottom.
I had the same issue when calling the function nanvar, and realised that there was a conflict with a function with the same name in the Fieldtrip toolbox (this Fieldtrip function calls nanvar_base). After removing the Fieldtrip/src folder from my paths, it worked fine.
I have been reading someone else's matlab code and I don't know how the code structured. I mean I would like to know the hierarchy of functions, which function uses which function. I am reading the code to figure that out but its taking a lot of time.
So is there any other way I can see this hierarchy without reading the whole thing? To be honest it is starting to get confusing. Maybe MatLab has a built in function for that! I found this:
How can I generate a list of function dependencies in MATLAB?
but this doesn't seem to be helpful!
The MATLAB profiler will show you what functions are called by your code (and much more information to boot) and allow you to click through the hierarchy of function calls. You can either call profile on and then run your code, then call profile off and profile viewer, or you can simply call profile viewer and type a single line of code to run in the edit box at the top.
Use the dependency report provided in MATLAB:
http://www.mathworks.co.uk/help/matlab/matlab_prog/identify-dependencies.html
There are also some tools on the File Exchange, such as fdep.
No idea about a function to show visible or depended-upon functions. However the basic rules are:
1) Only the first function in a .m file (normally has to have the same name as the file itself) is visible outside that file.
2) Any function can see any top level (see 1.) function if the file is in the matlab path. Matlab can show you the path so you know where it's hunting.
3) The order of the path is important, the first instance of a function called foo found in the path will be called. Obviously the current directory is at the top of the path.
3) All functions in a given file can see all other functions in that file.
That's the basics. No doubt there are other rules, and possibly exceptions to this. But that understanding generally serves me well.
Obviously the easiest way to work out which function is being called is to click on it in the editor and open it.
One thing I do is simply place in each function at the beginning fprintf("inside function <name>/n"); and at the end of the function fprintf("leaving function <name>/n"); where <name> is the name of the function.
This will give you a very specific list of which function is being called by which function (based on the order that they appear). Another thing like this would be to place fprintf("function <name1> calling function <name2>/n"); so you can be more explicit about which function is being called by which one.
I'm working on Iris recognition system for my degree project (put in mind i have no background in Matlab and i had no courses or anything in it , but i had to use it to implement my project ><) .
I'd like to ask , how can i use the output of a Matlab function in another function ?
Like how to take the output of a function , let's say "Segmentation" function , and pass it or use it in another function , like "Normalization" for example .
Is there any way to store it in a variable or something like that like in other programming languages ?
I hope you guys got what i mean & I hope i'll get an answer :)
Thank you :)
Just add an output argument to your first function, and an input argument to your second function, like so:
function theOutput = doSomething()
theOutput = someValue;
Then, the second function:
function doSomethingElse(theInput)
disp(theInput); % Will print value of someValue returned from first function, assuming you call doSomethingElse passing this value
If you are unfamiliar with these basic concepts, however, I would recommend reading up on the MATLAB language in general. Remember that the documentation contains a wealth of information on most topics. For this specific problem, see the function keyword documentation.
take 3 minutes to read any matlab getting started guide,
this one for example
http://alice.nc.huji.ac.il/~hvuag/neuromath/math/Matlab_Tutorial.pdf
Matlab is HUGE, and it can take you years to explore every corner,
the upside is , that you can be productive from minute 2. the easy things are very much straight forward.
to answer your question, variable assginment is trivial
a=max(1,2)
b=max(a,3)