I have created a plot in Matlab. Let's assume for simplicity that I have the following plot:
x = 0:pi/100:2*pi;
y = sin(x);
plot(x,y)
Now I would like to add vertical lines (going from the bottom of the figure to the top) at positions x = 1, x = 3 and x = 5. Additionally, the vertical lines should have text (next to the line or on top of the line). For example, for the line at x = 1 I would like to have the text "test 1".
How can this be done? This seems to be a pretty tricky thing in Matlab.
Here are some ways to draw lines:
x = 0:pi/100:2*pi;
y = sin(x);
plot(x,y,[1 1],[-1 1],[3 3],[-1 1],[5 5],[-1 1]);
x = 0:pi/100:2*pi;
y = sin(x);
plot(x,y); hold on;
for ind1 = 1:2:5
line([ind1 ind1],[min(y) max(y)],'Color',[0 0 0]);
end
x = 0:pi/100:2*pi;
y = sin(x);
A = zeros(6); A(sub2ind(size(A),1:6,[2 1 4 3 6 5])) = 1;
plot(x,y); hold on; gplot(A, [repelem(1:2:5,1,2).', reshape(repelem([1 -1],3,1).',[],1)]);
Etc.
Either use hold on and plot in several commands, or provide all inputs to your plot function right aways to get the desired result. Consult the documentation of the above functions for more information.
For texts refer to text.
for i=1:2:5
hold on
plot([i i],[0 1])
s=sprintf('test%1.0f', i)
t=text(i,1,s)
set(t,'Rotation',90)
end
Related
theta = linspace(0,2*pi,200); y = theta;x = 10;plot(x,y,'o');
When i write this i get the points but when i replace plot(x,y,'o') with plot(x,y) I should get a vertical line at x=4 but the graph comes empty..
You can use stem
x = 10;
y = 200;
stem(x,y,'Marker','none');
From this answer: https://it.mathworks.com/matlabcentral/answers/2031-adding-vertical-line-to-plot
fig=figure;
hax=axes;
x=0:0.1:10;
hold on
plot(x,sin(x))
SP=1; %your point goes here
line([SP SP],get(hax,'YLim'),'Color',[1 0 0])
Im new to matlab and I want to plot a ContourPlot together with two inequalities but I dont know how. The function that I want to plot its ContourPlot is something like this:
Z = (X-2).^2 + (Y-1).^2;
and here are the two inequalities:
ineq1 = X.^2 - Y <= 2;
ineq2 = X + Y <= 2;
this is what I have dodne so far:
[X,Y] = meshgrid(-4:.2:4,-4:.2:4);
Z = (X-2).^2 + (Y-1).^2;
[C,h] = contour(X,Y,Z);
clabel(C,h)
ineq1 = X.^2 - Y <= 2;
ineq2 = X + Y <= 2;
range = (-4:.2:4);
hold on
plot(range,ineq1, range, ineq2)
hold off
but this does not feel right.
What I want to do is to visualize an optimization problem. First I want to plot the ContourPlot of the function and then the possible areas in that same plot, It would be great if I could show the intersection areas too.
If you want to draw the boundaries of the inequalities onto the contour plot, you can do this with line.
[X,Y] = meshgrid(-4:.2:4,-4:.2:4);
Z = (X-2).^2 + (Y-1).^2;
[C,h] = contour(X,Y,Z);
clabel(C,h)
x_vect = (-4:.05:4);
y_ineq1 = x_vect.^2 - 2;
y_ineq2 = 2 - x_vect;
line(x_vect, y_ineq1);
line(x_vect, y_ineq2);
Coloring the intersection area is a bit more tricky, and I'm not sure if it's exactly what you want to do, but you could look into using patch, something like
% Indexes of x_vect, y_ineq1 and y_ineq2 for region where both satisfied:
region_indexes = find(y_ineq1<y_ineq2);
region_indexes_rev = region_indexes(end:-1:1);
% To plot this area need to enclose it
% (forward along y_ineq1 then back along y_ineq2)
patch([x_vect(region_indexes),x_vect(region_indexes_rev)],...
[y_ineq1(region_indexes),y_ineq2(region_indexes_rev)],...
[1 0.8 1]) % <- Color as [r g b]
% May or may not need following line depending on MATLAB version to set the yaxes
ylim([-4 4])
% Get the original plot over the top
hold on
[C,h] = contour(X,Y,Z);
clabel(C,h)
hold off
I have a function which is basically recreating the freqz command in matlab. I have figured out how to plot the entire transform of my frequency response, but I only need half of it, and I need to normalize it from pi to 1 (where 0:pi represents my x axis, and I want that to go to 0:1). The code is here:
function freqrespplot(b, a)
hb = fft(b,512);
ha = fft(a,512);
magh = (abs(hb) ./ abs(ha));
angh = angle(hb ./ ha);
x = linspace(0,2*pi, 512);
subplot(2,1,1);
plot(x,magh,'g');
subplot(2,1,2);
plot(x,angh,'r');
end
In the example of b = [1 2 2], a = [0 1 .8], plots like the following:
freqrespplot([1 2 2], [0 1 .8]);
Magnitude
and my corresponding phase plot is
I want the x-axis (omega) to go from 0 to 1 in both cases, and correspond to 0 to pi by taking only half of the graph, like this if possible:
You only need some small changes, marked with comments in the code below:
function freqrespplot(b, a)
hb = fft(b,512);
ha = fft(a,512);
magh = (abs(hb) ./ abs(ha));
angh = angle(hb ./ ha);
x = linspace(0,2, 513); %// 2, not 2*pi. And 513. Last value will be discarded
x = x(1:end-1); %// discard last value to avoid having 0 and 2*pi (they are the same)
subplot(2,1,1);
plot(x(1:end/2),magh(1:end/2),'g'); %// plot only half
subplot(2,1,2);
plot(x(1:end/2),angh(1:end/2),'r'); %// plot only half
end
With your example b and a this produces
You may want to include one additional sample to reach the right edge of the graph. I comment only differences with the above code:
function freqrespplot(b, a)
hb = fft(b,512);
ha = fft(a,512);
magh = (abs(hb) ./ abs(ha));
angh = angle(hb ./ ha);
x = linspace(0,2, 513);
x = x(1:end-1);
subplot(2,1,1);
plot(x(1:end/2+1),magh(1:end/2+1),'g'); %// plot only lower half plus one value
subplot(2,1,2);
plot(x(1:end/2+1),angh(1:end/2+1),'r'); %// plot only lower half plus one value
end
Compare the resulting graph (rightmost part):
I want to have grid with lines in it like this:
Currently, i have coded to get grid like this:
I just need to add horizontal and vertical lines in it.
MyCode:
[X,Y] = meshgrid(-1:0.1:1, -1:0.1:1);
X = X(:);
Y = Y(:);
plot(X,Y,'b.');
xlabel('X'); % // Label the X and Y axes
ylabel('Y');
title('Initial Grid');
To draw those lines, the easiest approach is two loops:
x = -1:0.1:1;
y = -1:0.1:1;
hold on
for n = 1:numel(x); %// loop over vertical lines
plot([x(n) x(n)], [y(1) y(end)], 'k-'); %// change 'k-' to whatever you need
end
for n = 1:numel(y); %// loop over horizontal lines
plot([x(1) x(end)], [y(n) y(n)], 'k-'); %// change 'k-' to whatever you need
end
Alternatively, you can use grid; but then you don't have control on line type. You get black dotted lines:
x = -1:0.1:1;
y = -1:0.1:1;
figure
set(gca,'xtick',x);
set(gca,'ytick',y);
axis([min(x) max(x) min(y) max(y)])
grid on
I would like to reproduce in Matlab a plot that looks like this:
The stem3 plot command sounds nice but only for the vertical stems. Not the second series with the horizontal ones.
Everything would be easy if I could plot using the usual commands and rotate the result.
How a about this? Manually plot each line in 3D stemming from the x axis:
x = 0:.01:2*pi*3;
z = sin(x);
y = -sin(x);
hold on
for n = 1:numel(x);
plot3([x(n) x(n)], [0 y(n)], [0 0], 'r');
plot3([x(n) x(n)], [0 0], [0 z(n)], 'b');
end
view(15,25)
As noted by #TheMinion, it's easier to use fill3:
x = 0:.01:2*pi*3;
z = sin(x);
y = -sin(x);
fill3(x,y,zeros(size(x)),'r')
hold on
fill3(x,zeros(size(x)),z,'b')
view(15,25)