I created a MATLAB function that runs bootstrap regression based on your data and the sample size desired. The only inputs required are the Y data, X data and 'n' the bootstrap sample size required, e.g. boot(Y,X,10).
How can I create an input that will loop for numerous sample sizes? I.e. something like boot(Y,X,[10,30,100]).
This is important as bootstrap can take quite a while to run, so it is ideal if you can just enter the desired sample sizes and leave the computer while running instead of entering the same command three times.
This can be done easily as follows:
bootstrapSampleSize = [10 30 100];
for i=1:length(bootstrapSampleSize)
yourResult{i}=boot(Y,X,bootstrapSampleSize(i)); %stores the results in a cell array
end
This can be made completely interactive with the use of input command but I will leave that upto you.
Related
I'm a super beginner in Simulink models and control systems.
I have .slx Simulink model for drone dynamics system.
It takes in two inputs (roll cmd, pitch cmd) and outputs velocity x, velocity y, position x, and position y.
From here, it seems like I can open the system by calling
open_system('myModel.slx', 'loadable');
But how do I put inputs and get output values?
Is there a way I can do this in a gui?
EDIT:
Here is the full layout of my model:
When I did
roll_CMD=10;
pitch_CMD=20;
I got a warning saying:
Input port 1 of 'SimpleDroneDynamics/...' is not connected.
How do I feed inputs using port numbers?
How do I get outputs with port numbers? I tried
[vx, vy, px, py] = sim('SimpleDroneDynamics.slx');
and got an error saying
Number of left-hand side argument doesn't match block diagram...
Is there a way to continuously feed inputs at every time step? This being controller module, I think I'm supposed to feed in different values based on output position and velocity.
EDIT2:
I'm using Matlab2017a
About the first two points of your question:
In simulink:
For the inputs you can use a constant block and when you double click the input block you can assign a value, which can be a workspace variable.
To get the outputs to your workspace you can use the simout block (make sure to put Save format to array).
Connect inputs to your simulink model
Connect outputs of your simulink model to the simout blocks.
MATLAB script
clc;
clear all;
roll = 10;
pitch = 20;
sim('/path_to_simulinkmodel.slx')
time = simout(:,1);
velocity_X = simout(:,2);
velocity_Y = simout(:,3);
position_X = simout(:,4);
position_Y = simout(:,5);
About the third point of your question
You can define the duration of your simulation in the block diagram editor. You can put a variable which is defined in the calling script. There are multiple ways of achieving time dependent input variables:
One option I personally don't recommend is using a for-loop and calling the simulink model with a different value of roll and pitch
for i = 1:numberOfTimesteps
roll = ...
...
sim('simulinkModel.slx')
end
A second and more efficient approach is changing the constant blocks to other source blocks like ramp signals or sinusoid signals
First of all Simulink model use main Matlab workspace. So you can change your variables values at command window (or just at your script) and run Simulink model.
There are several ways to initialize this constants for Simulink. One more useful way is to create script containing all your variables and load it at Simulink model starts. You can do it by adding script name in Simulink/Model Explorer/Callbacks. (There are different callbacks - on Loading, on Starting and etc.). Read more about this: here.
Now you can run your simulation using sim function:
sim('name_of_model')
name_of_model must contain path if model is not in the active MATLAB folder (active folder you can see in your matlab window just under the main menu).
There are different properties of sim function, read about them in help this can be useful for you. By the way: you can change some parameters of your model using sim. You even can find any block in your model and change it's properties. Read more about sim and about finding current blocks. Interesting that the last solution give you ability to change parameters during the simulation!
About getting output. After you run simulation you get tout variable in main workspace. It is an array of timesteps. But if you add outport block (like at my image) you also get another variable in workspace yout. yout is an Datasets. It contain all your outports values. For 2 outports for example:
yout
yout =
Simulink.SimulationData.Dataset
Package: Simulink.SimulationData
Characteristics:
Name: 'yout'
Total Elements: 2
Elements:
1 : ''
2 : ''
Get the values of any of outports:
yout.get(1).Values
it is a timeseries data type, so:
yout.get(1).Values.Time - give you times
yout.get(2).Values.Data - give you values of this outport at each time
We have one more method to take output values:
[t,x,y] = sim('model_name')
it returns double arrays. t- time array, y - matrix of all outports values (it already double and contain only values without times, but for each simulation time!)
So now you can create common Matlab GUI and work at this variables! There is no any difficulties. You can read more about GUI for Simulink here.
I have made a script which contains a for loop selecting columns from 533 different excel files and places them into matrices so that they can be compared, however the process is taking too long (it ran for 3 hours yesterday and wasn't even halfway through!!).
I know xlsread is naturally slow, but does anyone know how I can make my script run faster? The script is below, thanks!!
%Split the data into g's and h's
CRNum = 533; %Number of Carrington Rotation files
A(:,1) = xlsread('CR1643.xlsx','A:A'); % Set harmonic coefficient columns
A(:,2) = xlsread('CR1643.xlsx','B:B');
B(:,1) = xlsread('CR1643.xlsx','A:A');
B(:,2) = xlsread('CR1643.xlsx','B:B');
for k = 1:CRNum
textFileName = ['CR' num2str(k+1642) '.xlsx'];
A(:,k+2) = xlsread(textFileName,'C:C'); %for g
B(:,k+2) = xlsread(textFileName,'D:D'); %for h
end
Don't use xlsread if you want to go through a loop. because it opens excel and then closes excel server each time you call it, which is time consuming. instead before the loop use actxserver to open excel, do what you want and finally close actxserver after your loop. For a good example of using actxserver, search for "Read Spreadsheet Data Using Excel as Automation Server" in MATLAB help.
And also take a look at readtable which works faster than xlsread, but generates a table instead.
The most obvious improvement seems to be to load the files only partially if possible. However, if that is not an option, try whether it helps to only open each file once (read everything you need, and then assign it).
M(:,k+2) = xlsread(textFileName,'C:D');
Also check how much you are reading in each time, if you read in many rows in the first file, you may make the first dimension of A big, and then you will fill it each time you read a file?
As an extra: a small but simple improvment can be found at the start. Don't use 4 load statements, but use 1 and then assign variables based on the result.
As mentioned in this post, the easiest thing to change would be to set 'Basic' to true. This disables things like formulas and macros in Excel and allows you to read a simple table more quickly. For example, you can use:
xlsread('CR1643.xlsx','A:A', 'Basic', true)
This resulted in a decrease in load time from about 22 seconds to about 1 second for me when I tested it on a 11,000 by 7 Excel sheet.
how to use the "from workspace block in simulink" ?
I have tried using the from workspace block by given 10*2 matrix as input. it is appending some extra data along the data I have given .
and I have such 3 such blocks and want to know how I merge them.
Read the documentation. Simulink is time-based so the data in your From Workspace block must be as a function of time. Does your 10 x 2 matrix represent a signal as a function of time? If so, it needs to be as follows:
A two-dimensional matrix:
The first element of each matrix row is a
time stamp.
The rest of each row is a scalar or vector of signal
values.
The leftmost element of each row is the time stamp of the
value(s) in the rest of the row.
10 values isn't very much, it's likely that Simulink will need additional data points at intermediate times, if you have the Interpolate Data check box ticked. If not, "the current output equals the output at the most recent time for which data exists".
I think you may have a misunderstanding of the variables intended to be read by the FromWorkspace block.
The block expects a time series defining the value at various points in the simulation.
The From Workspace block help should point you in the right direction on this. Mathworks Help Documentation
I believe that something like the following would work for you:
>> WorkspaceVar.time=0;
>> WorkspaceVar.signals.values=zeros(10,2)
>> WorkspaceVar.signals.dimensions = [10,2]
Is there an option in matlab or a plugin/app or a trick such that if you are in an interactive command session, every time it would print out a matrix way too big for a human to look through, it redacts the output to either a warning of how big the matrix is or a summary (only a few rows and columns) of the matrix?
There are many times where I want to examine a matrix in the command window, but I didn't realize how big it was, so I accidentally printed the whole thing out. Or some place inside a function I did not code myself, someone missed a semicolon and I handed it a big matrix, and it dumps the whole thing in my command window.
It make sense that in 99.99% of the time, people do not intend to print a million row matrix in their interactive command window, right? It completely spams their scroll buffer and removes all useful information that you had on screen before.
So it makes much more sense for matlab to automatically assume that the user in interactive sessions want to output a summary of a big matrix, instead of dumping the whole thing into the command window. There should at least be such an option in the settings.
One possibility is to overload the display function, which is called automatically when you enter an expression that is not terminated by ;. For example, if you put the following function in a folder called "#double" anywhere on your MATLAB path, the default display behavior will be overridden for double arrays (this is based on Mohsen Nosratinia's display.m for displaying matrix dimensions):
% #double/display.m
function display(v)
% DISPLAY Display a variable, limiting the number of elements shown.
name = inputname(1);
if isempty(name)
name = 'ans';
end
maxElementsShown = 500;
newlines = repmat('\n',1,~strcmp(get(0,'FormatSpacing'),'compact'));
if numel(v)>maxElementsShown,
warning('display:varTooLong','Data not displayed because of length.');
% OR show the first N=maxElementsShown elements
% builtin('disp', v(1:maxElementsShown));
elseif numel(v)>0,
fprintf([newlines '%s = \n' newlines], name);
builtin('disp', v);
end
end
For example,
>> xx=1:10
xx =
1 2 3 4 5 6 7 8 9 10
>> xx=1:1e4
Warning: Data not displayed because of length.
> In double.display at 17
EDIT: Updated to respect 'compact' and 'loose' output format preference.
EDIT 2: Prevent displaying an empty array. This makes whos and other commands avoid an unnecessary display.
In the following code, I need 1 lakh samples in the array mydata. I don't know what I am getting out of mydata. Do I have to increase the range of t to get that. And how can I use the data in mydata into another .m file for further processing.
t = [ 1 : 1 : 500]; % Time Samples
f1=10000; % Input Signal Frequency
f2=20000;
f3=30000;
f4=f2+f3;
f5=f1+f3;
f6=f4+f2;
f7=f1+f6;
f8=45000;
f9=55000;
f10=35000;
mydata=[1:100000];
Fs = 100000; % Sampling Frequency
for i=1:100000
if(i<=10000)
mydata = sin(2*pi*f1/Fs*t);
elseif((i>10000)&&(i<=20000))
mydata=sin(2*pi*f2/Fs*t);
elseif((i>20000)&&(i<=30000))
mydata=sin(2*pi*f3/Fs*t);
elseif((i>30000)&&(i<=40000))
mydata=sin(2*pi*f4/Fs*t);
elseif((i>40000)&&(i<=50000))
mydata=sin(2*pi*f5/Fs*t);
elseif((i>50000)&&(i<=60000))
mydata=sin(2*pi*f6/Fs*t);
elseif((i>60000)&&(i<=70000))
mydata=sin(2*pi*f7/Fs*t);
elseif((i>70000)&&(i<=80000))
mydata=sin(2*pi*f8/Fs*t);
elseif((i>80000)&&(i<=90000))
mydata=sin(2*pi*f9/Fs*t);
elseif((i>90000)&&(i<=100000))
mydata=sin(2*pi*f10/Fs*t);
end
end
stem(mydata)
your code doesn't do very much; you know that, right?
if we don't know/understand what you want, we can't help..
and for anyone else: 1 lakh = 100 000 (http://en.wikipedia.org/wiki/Lakh)
edit: are you trying to produce an array of 100000 samples, consisting of a fixed number of points from different sine waves? aka:
[sin(1.0*pi*[0:10]) sin(2.0*pi*[0:10] sin(1.5*pi*[0:10] (etc) ]
edit2: you repeated your earlier question (which was already answered): How can I generate a sine wave with different frequencies using matlab?
I couldnt understand what you want to do with mydata, please be more specific, because your code is wrong and I cant figure what you want to create.
Whereas for the problem on having the data to be used on other script one simple way would just write mydata into disc,
by doing on your script:
save path_for_mydata/file_name.mat mydata
And on the other script:
load path_formydata/file_name.mat
One other way, would be to create a function, and pass it as a parameter.
Finally, you could just run the first script, and then the second script on command line or on one third script that would call this both scripts, the parameters from the first script will be saved on transient memory while the second script runs.