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I have an array of structs. Every struct holds a set of data for one single measure. Matlab gives me an error when I try to plot this data.
Expected one output from a curly brace or dot indexing expression, but there were 361 results.
How should I rewrite my plot code?
plot(result.structArray_A(:).nonArrayValue_X, result.structArray_A(:).nonArrayValue_Y);
I have found a solution. Simply writing the following does work, even if the syntax does look odd:
plot([result.structArray_A.nonArrayValue_X], [result.structArray_A.nonArrayValue_Y]);
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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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For matalb there's an error at line 9, where I define dy(1), but it doesn't say what kind of error.
function dy=pred_prey(t,y)
k=1;
a=2/3;
d=4/3;
f=#(x)cos(x.^2)
r=#(t)integral(f,0,t);
mu=#(t)13/20-(3/5)*exp(-(3/t));
dy(1)=(y(1)+k)*r-a*y(1)*y(2);
dy(2)=-mu*y(2)+d*y(1)*y(2);
dy=dy';
You define r as an anonymous function, but you don't pass any arguments to it when you call it on line 9. The line should be (I assume):
dy(1) = (y(1)+k)*r(t)-a*y(1)*y(2);
Incidentally, you're going to have the same problem on the next line where you call mu with no arguments as well.
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I want to draw a line using the inputs for values x1,y1 and x2,y2 from the gui edit text box and plot them on the axes.
function
You are trying to convert the graphics handle itself to a number rather than converting the contents of the uicontrol to a number. To get the value, you'll want to use the 'String' property of the uicontrol instead.
x1 = str2double(get(handles.edit1, 'String'));
You will want to do the same for all user-supplied values.
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I watched a video titled "Writing a matlab program" and tried to use the syntax exactly, yet I still can't see how I've made an error...can you please help?
My code is simply
x= [-10:0.1:10];
y=2x^2-x + 1;
plot (x,y)
I'm getting a parse error at x and I have no idea what that means..
Matlab cannot parse 2x. Multiplication requires the * symbol. Either * or .* will work in this case.
Your next problem will be the use of ^ instead of .^ —this time you're going to have to include the dot. Google for "elementwise" operators in matlab to understand what difference the dot makes.
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I'm using the computer vision: VLfeat library to compute a HOG descriptor of an image, and after inputing this code:
cellSize = 8 ;
hog = vl_hog(im, cellSize, 'verbose') ;
I get this error in MATLAB, and when I google it I really can't find any possible explanation:
Error using vl_hog
I is not a real numeric array of class SINGLE.
After going over the code (found here) I'm also not sure what the variable I is:
Hopefully, I haven't missed something elementary ...
library source
As the asker already found out, the I refers to the first input argument.
Hence this should solve the problem:
hog = vl_hog(single(im), cellSize, 'verbose')