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I have the following code:
for i = 1:RGB_size(2) % RGB_size(2) = 1296 //X coords
for j = 1:1:RGB_size(1) % RGB_size(1) = 964 //Y coords
if mask(i,j) == 1
data(next_pixel,:) = [ImgIndex, ImgTake, i, j, RGB(i,j,1), RGB(i,j,2), RGB(i,j,3),...
HSIR(i,j,1), HSIR(i,j,2), HSIR(i,j,3)];
next_pixel = next_pixel + 1; %get next pixel
end
end
end
But Matlab won't run my code because it says I'm trying to access mask(965,1) and my variable mask size is 1296×964. However, I don't see how this is possible. Any thoughts?
RGB_size is calculated from a variable called RGB, which is the same variable used to create the variable mask. I have verified that they are both the same size with the debugger.
Actual error message is:
Attempted to access mask(965,1); index out of bounds because size(mask)=[964,1296].
You have switched the i and j index of the mask.
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IND_STRT = 0;
ALL_STRT = IND_STRT:12:510;
cmd_data = zeros(length(ALL_STRT),1); %example: x=zeros(1,21) gives you a 1 by 21 matrix
for ii = 1:length(ALL_STRT) %declare variable ii to run from the row of length
if ~isempty(data{i})
cmd_data(ii) = cell2mat(textscan(char(data{i}(ALL_STRT(ii):(ALL_STRT(ii)+4))),'%f'));
end
end
I need to read the EPS from EnduroSat, however i have difficulty understanding the line cmd_data(ii) = cell2mat(textscan(char(data{i}(ALL_STRT(ii):(ALL_STRT(ii)+4))),'%f'));
Im required to utilised MatLab to code and this particular line have an error and i don't understand why.
Whenever you see a complicated line like this in MATLAB, try to break it up.
% find some indices. These values have been selected by the programmer/data, can't say why.
a=ALL_STRT(ii):(ALL_STRT(ii)+4)
% obtain that articular section of the data
b=data{i}(a)
% convert it to a char data type (characters)
c=char(b)
% scan text, and treat them as float
d=textscan(c,'%f')
% the output is a cell array, we want a matrix instead. Make the cell array into a matrix.
cmd_data(ii) = cell2mat(d)
You can read particularly what each of these do better in their documentation pages, and you can see it work if you put a break-point in the code, and see what each of this parts output when you call it. Learn how to debug, is a very very powerful tool
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I am new to MATLAB, I have created a triangle, I used the code as below to find all coordinates of x,y.
side_1=[linspace(3,5,100);linspace(2,3,100)]
side_2=[linspace(5,4,100);linspace(3,5,100)]
side_3=[linspace(4,3,100);linspace(5,2,100)]
all_coordinates=[side_1,side_2,side_3]
I used the code as below to find angles.
angles=zeros(300,1);
for i=1:300
angles(i)=atan(all_coordinates(2,i)/all_coordinates(1,i))*180/pi
end
Since view point is flatview, y=0, x=angles
I used this code to plot angles.
for i = range(length(angles))
scatter(angles(i),0)
end
Got error array indices must be positive integers or logical values.
Not sure what you are trying to do with the loop but the problem is that you last loop is wrong.
range(length(angles)) =0, you should use for i=1:length(angles) instead
In addition the two loops are unnecessary. Not sure what you are trying to do with the scatter plot, but you can just write:
angles=atan(all_coordinates(2,:)./all_coordinates(1,:))*180/pi
figure
scatter(angles,zeros(1,length(angles)))
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I want to define a vector y=[sin(1),sin(1/2),...,sin(1/1000)].
but I don't know how to do that. I defined
for i=1:1000
y(i)=sin(1/i);
end
but this does not work.
Just define the y as the following (and initialize to get the better performance):
y = zeros(1, 1000);
for i = 1:1000
y(i) = sin(1/i);
end
Also you can do it without for:
y = sin(1./(1:1000));
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I have a huge amount of data to plot, and thanks to:
x=matlab.lang.makeValidName(strcat(...));
assignin('base',x,I);
for each loop of process, where I calculate I, I assign the value of I (a vector) to the variable name I_Pnum1_Bnum2 where num1 is the value of P and num2 the value of B. So, at the end I have lots of I's for:
num1=-4:-1:-14;
num2=[0 5 10 20:20:120 150 170 200 220];
That's why, for each value of P, I want to plot (on the same graph) all I's for different B:
num1=-4:-1:-14;
num2=[0 5 10 20:20:120 150 170 200 220];
for i=1:length(num1)
legend=[];
figure(i)
for j=1:length(num2)
Y=matlab.lang.makeValidName(strcat('I_p',num2str(abs(num1(i))),'_B',num2str(double(num2(j)))));
plot(V,eval(Y),'linewidth',2)
hold on
leg=strcat("B= ",num2str(b(j)));
legend=[legend leg];
end
title(strcat("Caractéristiques I(V) #",num2str(p(i)),"dBm"))
legend(legend);
end
clc;
The problem: I get
Function 'subsindex' is not defined for values of class 'string'.
and it is due to the line legend(legende), and I don't understand why, because the vector legende is well defined.
The error occurs because of a conflict between your variable named legend and the build-in MATLAB function legend(). Rename your variable to e.g. leg1 then it should work as expected.
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I have this function
h45 = #(x) 1 / (1 + exp(-thDesnorm' * [1 45 x]'));
where thDesnorm is:
[-23.6608
0.1919
0.1866]
When i want to plot this function this way:
domain = 0:1:100;
figure;
plot(domain, h45(domain));
I get this error:
Error using *
Inner matrix dimensions must agree.
Error in #(x)1/(1+exp(-thDesnorm'*[1,45,x]'))
This function works when calling it with, for example, h45(1).
I guess than in plotting, the function is receiving all the domain vector as the parameter x, and not one by one the values of this vector.
As you guessed, the parameter x is your full array domain. This obviously causes a dimensional error in the dot product thDesnorm'*[1,45,x]. A quick fix would be using arrayfun to evaluate h45. For instance:
thDesnorm = [-23.6608
0.1919
0.1866];
h45 = #(x) 1 / (1 + exp(-thDesnorm' * [1 45 x]'));
domain = 0:1:100;
figure;
plot(domain, arrayfun(#(x)h45(x),domain)) % See modification in h45 call