I'm trying to write a function that iteratively loops through a bunch of .txt files in a directory and processes them individually. After a file has been processed I would like to plot output variables, then on the next iteration plot the new variables on the same graph. My code is shown below however does not seem to be working, it returns a 'output argument 'output1' (and maybe others) not assigned during call to function2.
Currently my code looks something like this:
function [output1, output2, fig] = Processing(Folder_1,Folder_2,Folder_3)
%% Read in all the Data
% Initialise Loop to process each file independently
for i = 1 : length(Text_Files1)
Sorted_Index1 = Indices1(i);
Path1 = fullfile(Folder_1,Text_Files1(Sorted_Index1).name);
Table1 = readtable(Path1);
Sorted_Index2 = Indices2(i);
Path2 = fullfile(Folder_2,Text_Files2(Sorted_Index2).name);
Table2 = readtable(Path2);
Sorted_Index3 = Indices3(i);
Path3 = fullfile(Folder_3,Text_Files3(Sorted_Index3).name);
Table3 = readtable(Path3,'Delimiter',';');
%% Process Data through the Loop
[HR] = function1(processed_data)
[output1 output2] = function2(HR, Time);
hold on
fig = figure('Visible', false);
subplot(10,10,1:90)
plot(output2, output1, 'Color', [0.92 0.47 0.44], 'LineWidth', 1.5);
end
end
%% Function 2:
function [output1, output2] = function2(t, y, z)
segment = 1:z:max(y);
% Iterate through each time segment and calculate average t value
for x = 1:length(segment)-1
SegmentScores = find(y > segment(x) & ...
y < segment(x+1));
output1(x) = mean(y(SegmentScores));
output2(x) = Segment(x+1);
end
end
The problem is that you're calling function2(HR, Time) with two inputs, while it needs three function2(t, y, z).
For that reason, I'm assuming that inside function2 segment is an empty array, and thus the loop for x = 1:length(segment) - 1 is not entered at all.
Since the definition of output1 and output2 is only inside the loop, they will never be created and thus the error.
If you provide three inputs to your function2, the problem will be solved. Just pay attention to the order in which you provide them (for example, I'm assuming your Time input should be the same as t in the function, so it should be the first input to be passed).
Related
I've written the following piece of subcode (with parameters commented) for an Euler policy iteration algorithm. When I try to run the body of the function (everything below global) for say, a1 = 1, it works, and returns a scalar. However, when I call the function as euler_diff_test(1), I get an error. (Pasted below)
function diff = euler_diff_test(a1)
%the following comments are example parameters. They are in the global line originally.
% r = 0.2, a = 0.5, y = 1.1, a_grid = linspace(0.5,7,100)
%policy_guess = zeros(2,N);
%policy_guess(1,:) = 0.3*a_grid;
%policy_guess(2,:) = 0.3*a_grid;
% M = zeros(2,2); %M for markov transition kernel
% M(1,1) = p;
% M(2,2) = p;
% M(2,1) = 1-p;
% M(1,2) = 1-p;
% j = 1
global r a y a_grid policy_guess M j;
c = (1+r)*a + y - a1; %consumption formula
if c<=1e-02 %don't care about consumption being negative
diff = 888888888888888888888;
else
policy_func = interp1(a_grid', policy_guess', a1, 'linear');
diff = 1/c - beta*(1+r)*(1 ./ policy_func)*M(j,:)';
end
end
Error Reads:
Any help is much appreciated!
The problem is that you dont understand globals nor how they work!
You seem to be doing something like:
N=100; p=0.1;
r = 0.2, a = 0.5, y = 1.1, a_grid = linspace(0.5,7,100)
policy_guess = zeros(2,N);
policy_guess(1,:) = 0.3*a_grid;
policy_guess(2,:) = 0.3*a_grid;
M = zeros(2,2); %M for markov transition kernel
M(1,1) = p;
M(2,2) = p;
M(2,1) = 1-p;
M(1,2) = 1-p;
euler_diff_test(1)
And this is causing the error you show. Of course it is!
First, you need to learn what a global is and what worskpaces are. Each fucntion has its own worskpace or "scope". That means that only variables defined within the workspace are visible by the function itself.
A global variable is one that exist for all workspaces, and everyone can modify it. You seem to want all those variables defined outside the function, inside your function. But realise! when the variables are defined, they are not global. The function starts, and in its first line, it does only know about the existence of a1. Then, later, you define a bunch of variables as global, that the function did not know about. So what does the function do? just create them empty, for you.
If you want your the variables that you create in the main script scope to be global, you need to declare them as global then, not inside the function. So cut your line global ... from the fucntion, and put it on top of the script where you declare all your variables, i.e. on top of
% here!
N=100; p=0.1;
...
in my example.
Now, the important stuff: Global variables are bad. When you have globals, you don't know who modifies, and its super easy to lost track of what is happening to them, because every function that uses a variable a will modify the global a, so its a pain to debug. Almost no one uses globals because of this. The best way is to pass them to the function as input, i.e. define your function as:
function diff = euler_diff_test(a1,r, a, y, a_grid, policy_guess, M, j)
This is a followup to a previous issue I was having.
I want to give an offset to a signal then add some delay in it and calculate RMSE for that but when taking difference I am having the following issue:
I would like to ask the following things:
How can I solve the above problem?
Will anybody please explain in simple words what iddata does - because I have studied different portals including MATLAB but remained unable to get a good concept.
How can I store data of type iddata in cell for subtraction in the last part of my code?
Code with Problem :
drv(1)=load('123.mat');
t = drv(1).x;
ref = drv(1).y;
angle = drv(1).z;
Fs = 1000;
t1 =t';
ref1= ref';
d_data = iddata(ref1, t1, 1/Fs);
%% Add offset:
x = 1;
afterOffset1= {};
for i = 100:10:130
T = getTrend(d_data);
% <detrend data if needed>
T.InputOffset = i;
T.OutputOffset = i;
afterOffset = retrend(d_data,T);
afterOffset1{x,1}= afterOffset;
x= x+1 ;
end
%% Add delay:
y=20;
afterDelay1= {};
for i = 1:1:4
% delaySamples = i; % Must be a non-negative value
% afterDelay = iddata([NaN(delaySamples,1); d_data.OutputData],...
% [d_data.InputData; NaN(delaySamples,1)], 1/Fs);
afterOffset1{i}.Tstart = y;
afterDelay1{i,1}= afterOffset1{i};
y= y+10;
end
%% Plot:
n = size(afterDelay1,1);
figure();
for i=1:1:n
subplot(2,2,i);
plot(d_data);
hold all
plot(afterDelay1{i});
end
sig_diff = angle(1)-afterDelay1;
square_error(i,:) = (sig_diff(i)).^2;
mse(i,:)= mean(square_error(i));
rmse(i,:) = sqrt(mse(i));
sig_diff = d_data_1 - afterDelay; % <<<<<<<<<<<<<<<<<<<<<< Problem is here
% square_error = (sig_diff).^2;
% mse= mean(square_error);
% rmse = sqrt(mse);
end
You most likely want the OutputData attribute from the iddata object which is the output or y signal of your problem:
sig_diff = angle(1)-afterDelay1.OutputData;
Also note that this will give you a column vector, but your code later on assumes it's a row vector. You may want to transpose this data after you perform the above calculation before proceeding:
sig_diff = angle(1)-afterDelay1.OutputData;
sig_diff = sig_diff.';
In general, iddata is a function that creates an object that represents input and output time or frequency domain data. Take note that when you create an iddata object, the input matrix can potentially have multiple sources and so each column dictates a source. The same can be said for the output where each column dictates an output. Therefore, it is very important that you transpose your data prior to using this function to ensure that each signal is in a separate column, or just use a single column to represent one input / output.
Inside the object has a variety of attributes, including the sampling time or sampling frequency, the valid domain and range that the function takes on and finally accessing the input and output data. OutputData is one of these fields. I'd recommend looking at the documentation that talks about all of the attributes that you can access with iddata. OutputData is clearly defined here: https://www.mathworks.com/help/ident/ref/iddata.html
I have the following code which eventually outputs a graph and a 'groups' value. The results are dependent on a random function so can provide different results every times.
function [t seqBeliefs] = extendedHK(n, tol, adj)
%extendedHK Summary of function goes here
%Detailed explanation goes here
beliefs = rand(n,1);
seqBeliefs = beliefs; %NxT matrix
converge = 0;
step = 0
t = step
while converge ~= 1
step = step+1;
t = [t step];
A = zeros (n,n);
for i=1:1:n
for j=i:1:n
if abs(beliefs(i) - beliefs(j)) < tol && adj(i,j)==1
A(j,i)=1;
A(i,j)=1;
end
end
end
beliefs = A*beliefs./ sum(A,2);
seqBeliefs = [seqBeliefs beliefs];
if sum(abs(beliefs - seqBeliefs(:,step)))<1e-12
converge = 1;
end
end
groups = length(uniquetol(seqBeliefs(:,step), 1e-10))
plot(t,seqBeliefs)
end
In command window type
adj=random_graph(n)
I usually use n as 100 then call extendedHK function with same n then tol value (I usually choose between 0.1 and 0.4) and 'adj'
e.g. adj = random_graph(100)
extendedHK(100, 0.2, adj)
What I now need help with is running this function say 100 times, and taking an average of how many 'groups' are formed.
First, include the parameter "groups" in your function output. to do so, try this instead of the first line of your code:
function [t seqBeliefs groups] = extendedHK(n, tol, adj)
then save this function in a extendedHK.m file.
open another .m file, say console.m and write this:
results = zeros(1,100);
for i = 1:100
% set n, tol and adj inputs here <=
[~,~,out] = extendedHK(n, tol, adj);
results(1,i) = out;
end
avg = mean(results)
don't forget to define "results" out of the loop. since parameters that change size every loop, will make your code slow
(suppressing unnecessary outputs with ~ added later to this reply)
It is not clear if you need the current outputs of extendedHK:[t seqBeliefs]
Anyhow, you can add "groups" to the output and then from the console
N=100;
groups_vec = zeros(1,N);
for i=1:N
adj = random_graph(100);
[~,~,groups_vec(i)] = extendedHK(100, 0.2, adj);
end
groups_avr = mean(groups_vec);
note that if you use this code you won't be able to "see" the graphs as they will be cleared every loop iteration. you can do one of the following (1) add "figure;" before the plot command and then you will have 100 figures. (2) add "pause" to wait for key press between each graph. (3) add "hold on" to print all graphs on the same figure.
I was trying to plot function return values, one based on another. My function definition is:
function [final_speed, voltage] = find_final_speed(simulink_output)
As you can see, it returns two variables. I need a matrix that looks like this:
final_speed_1 voltage_1
final_speed_2 voltage_1
final_speed_3 voltage_1
final_speed_4 voltage_1
final_speed_5 voltage_1
In the end, voltages should be plotted on X axis, speeds on Y axis.
I originally tried this:
speedpervoltage = [find_final_speed(DATA_1); find_final_speed(DATA_2); ... ];
But that would only result in this matrix, all voltage info gone:
final_speed_1
final_speed_2
...
After all google searches and attempts failed, I did this:
[s1 v1] = find_final_speed(DATA_1);
[s2 v2] = find_final_speed(DATA_2);
[s... v...] = find_final_speed(DATA_...);
speedpervoltage = [0 0;s1 v1;s2 v2;s... v....;];
% Just contains the figure call along with graph properties.
plot_speedpervoltage(speedpervoltage);
This is really not optimal or practical solution. How can I do this more dynamically? Ideally, I'd like to have function create_speedpervoltage which would take array of data matrixes as argument:
plot_speedpervoltage(create_speedpervoltage([DATA_1 DATA_2 ...]));
if you know how many datasets you have, you encapsulate everything in a for loop like this:
Data = [DATA_1, DATA_2,....DATA_N] ;
outMat = [] ;
for i = 1 : length (Data)
[s v] = find_final_speed(Data(i));
outMat = [outMat ; s,v]
end
There is an easy way of doing this in Matlab. This answer is different from User1551892's answer because it doesn't dynamically reallocate the variable thus resulting in faster performance. The code is as follows.
% Declare Return Vectors
final_speed = zeros(20,1);
voltage = zeros(20,1);
% Loop through each data point
for i = 1: length( data )
[final_speed(i,:),voltage(i,:)] = find_final_speed( data(i) );
end
Now this assumes that data is a vector with each element corresponding to final and voltage speeds.
EDIT:
Another method to improve the speed even more is using arrayfun. Assuming your data is 1D, by feeding in the function as a handle into arrayfun, you can replace the 3 line loop with this line and preallocation with this code, which should give you even better performance and less lines.
[final_speed,voltage] = arrayfun( #find_final_speed, data );
Here is a solution with cellfun.
[s, v] = cellfun(#find_final_speed, [{DATA_1}, {DATA_2},... {DATA_N}]);
speedpervoltage = [s(:) v(:)];
I am trying to write a function transform(A) which when given a matrix A returns a new matrix. The new matrix should be obtained according to following:
if A has more than one row then interchange the first and second row. After this square the elements in the first row.
So far thats what I have written:
function[Anew] = transform(A)
dimension = size(A);
if dimension(1) > 1 %if there is more than 1 row
A([1 2],:)=A([2 1],:);
end
A(1,:,:) = A(1,:,:).^2 %squares elements in the first row
end
I tested my function by invoking it in matlab.
I noticed that because i dont have a semi colon next to A(1,:,:) = A(1,:,:).^2
I still obtain the desired result but not as output of the function.
I obtain A =
instead of Anew =
If i put a semi colon next to A(1,:,:) = A(1,:,:).^2; then I dont get an output at all.
Could you tell me what is wrong and what should I change in my program to obtain output as Anew?
Thank you
To return a value from a function in Matlab, you must directly assign to it.
In your case, you need to assign to Anew at the end of the operation (you could also technically just use that variable all-together).
function [Output1, Output2] = SomeFunction( ... )
% Do Some Work
% Store Output
Output1 = Result1(:,2) %some output
Output2 = Result2(3:end, :) %some other result
end
function[Anew] = transform(A)
dimension = size(A);
Anew = A;
if dimension(1) > 1 %if there is more than 1 row
Anew ([1 2],:)=Anew([2 1],:);
end
Anew(1,:,:) = Anew(1,:,:).^2; %squares elements in the first row
end