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I want to plot y=omega*x^2, which omega is -3 into 3 with step size 0.25, x from -4 into 4 with step size 0.001. But this code give me the curve is cannot moving and axes is moving. I want the curve is moving, like this.
x=-4:0.001:4;
for omega=-3:0.25:3
for i=1:length(x)
y(i)=omega*x(i)^2;
end
plot(x,y);
pause(0.1);
end
How to do that?
As another answer has indicated, you need to set the axis limits.
(Also note that there is no reason to calculate y using a loop.)
But instead of using plot every time through the loop it's more efficient to create the line only once, and then replace the x and y data of the line each time through the loop.
x=-4:0.001:4;
all_omega=-3:0.25:3;
for idx = 1:numel(all_omega)
omega = all_omega(idx);
y=omega*(x.^2);
if idx == 1
% create line
hl = plot(x,y);
axis([-4,4,-40,40]);
box on
grid on
else
% replace line data
set(hl,'XData',x,'YData',y);
end
title(sprintf('\\Omega = %.2f',omega));
pause(0.1);
end
Or you might want to use animatedline,
x=-4:0.001:4;
all_omega=-3:0.25:3;
for idx = 1:numel(all_omega)
omega = all_omega(idx);
y=omega*(x.^2);
if idx == 1
% create animated line
am = animatedline(x,y);
axis([-4,4,-40,40]);
box on
grid on
else
% replace the line
clearpoints(am)
addpoints(am,x,y);
end
title(sprintf('\\Omega = %.2f',omega));
pause(0.1);
end
A quick method is setting the x- and y-axes limits in the loop after each plot, using the axis([xmin, xmax, ymin, ymax]) command. This method isn't foolproof, in the case that the script gets help up after plotting but before setting the axes limits, but in most cases it should work.
figure(1)
x=-4:0.001:4;
for omega=-3:0.25:3
for i=1:length(x)
y(i)=omega*x(i)^2;
end
plot(x,y);
axis([-4 4 -50 50])
pause(0.1);
end
This is the same as #phil-goddard's answer, but makes more efficient use of handles to the animated YData and title string.
x = -4 : 0.001 : 4;
y = zeros(1, numel(x));
omega_range = -3 : 0.25 : 3;
% Create line and title, and obtain handles to them.
h_plot = plot(x, y);
axis([-4, 4, -40, 40]);
box on;
grid on;
h_title = title(sprintf('\\omega = %.2f', 0));
for idx = 1:numel(omega_range)
omega = omega_range(idx);
y = omega * (x.^2);
% Replace y data.
h_plot.YData = y;
% Replace title string.
h_title.String = sprintf('\\omega = %.2f', omega);
pause(0.1);
end
I have written a code to save two movies in Matlab. The problem is that, the movie "graphh.avi" is consist of first movie("chert") also. I want it to show just graphs and not the first saved movie("chert.avi").
Could anyone help? Any answer is highly appreciated.
clear all
close all
cla
h = plot(x, y, '.g', 'MarkerSize', 10);
set(gca,'Color',[0 0 0]);
set(gcf,'doublebuffer','on')
set(gca,'YTick',[]);
set(gca,'XTick',[]);
plot(x,y,'.g','markersize',10)
drawnow
currFrame = getframe;
writeVideo(vidObj,currFrame);
h = plot(x, y, '.g', 'MarkerSize', 10);
drawnow
hist(blocksize)
currFrame = getframe;
writeVideo(vid,currFrame);
end
close(vidObj);
close(vid)
The code after doing the first answer becomes as below. The problem solved but there is another problem now: black movie with green points became so messy.
clear all
close all
l = 20;
r = 3;
v = 0.5;
dt = 1;
nn=200;
figure(h1); % set figure 1 as current figure
h = plot(x, y, '.g', 'MarkerSize', 10);
set(gca,'Color',[0 0 0]);
set(gcf,'doublebuffer','on')
set(gca,'YTick',[]);
set(gca,'XTick',[]);
plot(x,y,'.g','markersize',10)
drawnow
currFrame = getframe(h1); % gets only figure 1
writeVideo(vidObj,currFrame);
h = plot(x, y, '.g', 'MarkerSize', 10);
drawnow
figure(h2); % set figure 2 as current figure
hist(blocksize)
currFrame = getframe(h2); % gets only figure 2
writeVideo(vid,currFrame);
end
close(vidObj);
close(vid);
Use figures handles when calling getframe. See how I modified your code:
% some code...
vvy = v.*sin(tetha);
h1 = figure('Color',[0 0 0])
axis([0 l 0 l])
% some more code...
h2 = figure
hold on
vid = VideoWriter('graphh.avi');
% and more code...
% for loop
figure(h1); % set figure 1 as current figure
% plot whatever on this figure
currFrame = getframe(h1); % gets only figure 1
writeVideo(vidObj,currFrame);
% blah blah...
figure(h2); % set figure 2 as current figure
% plot whatever on this figure
currFrame = getframe(h2); % gets only figure 2
writeVideo(vid,currFrame);
% end of loop
EDIT:
in your modified code you're calling h = plot(x, y, '.g', 'MarkerSize', 10); three times in a row for no reason, so get rid of it. the problem you encountered stems from plotting another set of point in addition to the previous one, so the axes get filled with points. One solution for that is to use set(h,'XData',x,'YData',y) like so:
figure(h1); % set figure 1 as current figure
set(gca,'Color',[0 0 0]);
set(gcf,'doublebuffer','on')
set(gca,'YTick',[]);
set(gca,'XTick',[]);
if exist('h','var') && ishandle(h) % if handle exists just change coordinates
set(h,'XData',x,'YData',y)
else % only for the first time you plot that
h = plot(x, y, '.g', 'MarkerSize', 10);
end
drawnow
currFrame = getframe(h1); % gets only figure 1
writeVideo(vidObj,currFrame);
i'm struggling with this matter probably
i'm just starting with Matlab.this is my code,i
wanna rotate a two links arm,using rotation matrix:
clear all
close all
clc
myaxes = axes('Xlim',[-1 1 ],'Ylim',[-1 1],'Zlim',[-1 1]);
view(3);
grid on;
axis equal;
hold on
xlabel('X')
ylabel('y')
zlabel('Z')
P_0 = [0; 0; 0] ;
P_1 = [-0.5;0; 0] ;
P_2 = [-1; 0; 0] ;
alfa_1 = 0:1:30 ;
alfa_2 =(0:0.5:15) ;
for i = 1:length(alfa_1)
M3(:,:,i) = [cosd(alfa_1(i)) -sind(alfa_1(i)) 0
sind(alfa_1(i)) cosd(alfa_1(i)) 0
0 0 1] ;
P_1(:,i,i) = M3(:,:,i)*[-0.5;0; 0] ;
P_2(:,i,i) = M3(:,:,i)*[-1;0; 0];
figure(1)
line([0 P_1(1,i,i)],[0 P_1(2,i,i)],[0 P_1(3,i,i)]);
scatter(P_1(1,i,i),P_1(2,i,i));
hold on
M3_1(:,:,i) = [cosd(alfa_2(i)) -sind(alfa_2(i)) 0
sind(alfa_2(i)) cosd(alfa_2(i)) 0
0 0 1] ;
P_2_2(:,i,i) = M3_1(:,:,i)*P_2(:,i,i);
line([P_1(1,i,i) P_2_2(1,i,i)],[P_1(2,i,i) P_2_2(2,i,i)],[P_1(3,i,i) P_2_2(3,i,i)],'color','r');
scatter(P_2_2(1,i,i), P_2_2(2,i,i))
hold on
end
should i use delete function to obtain an animation without plotting
all the lines but only the current line?!?.
thanks in advance for your help and support.
You can use the drawnow function in MATLAB for this purpose. This function can be used inside a for loop to force a plot to be rendered every iteration, instead of being stored in a buffer until after the loop.
Update figure window and execute pending callbacks
An example: for a simpler code consider a object moves on circle
t = 0:0.05:2*pi;
x = cos(t);
y = sin(t);
for k=1:length(t)
plot(x(k),y(k),'ko')
axis([-1.2 1.2 -1.2 1.2])
axis square
drawnow
end
Please note the axis function in this method. If the axis lines are deleted from the code then, in every iteration, the axis limits will change and the animation is not smooth.
What about your code:
clear all
close all
clc
view(3);
xlabel('X');
ylabel('y');
zlabel('Z');
P_0 = [0; 0; 0] ;
P_1 = [-0.5;0; 0] ;
P_2 = [-1; 0; 0] ;
alfa_1 = 0:1:30 ;
alfa_2 = (0:0.5:15) ;
for i = 1:length(alfa_1)
% Calculate new values for plotting
M3(:,:,i) = [cosd(alfa_1(i)), -sind(alfa_1(i)), 0
sind(alfa_1(i)), cosd(alfa_1(i)), 0
0 , 0 , 1] ;
P_1(:,i,i) = M3(:,:,i)*[-0.5; 0; 0] ;
P_2(:,i,i) = M3(:,:,i)*[-1; 0; 0] ;
% Clear figure 1 and hold for all plots
figure(1)
clf
% Hold only needs to be applied around plots on same axes
hold on
line([0 P_1(1,i,i)],[0 P_1(2,i,i)],[0 P_1(3,i,i)]);
scatter(P_1(1,i,i),P_1(2,i,i));
% Recalculate plotting values
M3_1(:,:,i) = [cosd(alfa_2(i)), -sind(alfa_2(i)), 0
sind(alfa_2(i)), cosd(alfa_2(i)), 0
0 , 0 , 1] ;
P_2_2(:,i,i) = M3_1(:,:,i)*P_2(:,i,i);
line([P_1(1,i,i) P_2_2(1,i,i)], [P_1(2,i,i) P_2_2(2,i,i)], [P_1(3,i,i) P_2_2(3,i,i)], 'color', 'r');
scatter(P_2_2(1,i,i), P_2_2(2,i,i))
% Set axis limits for consistency in all plots, show grid
axis([-2 2 -2 2])
grid on
% Hold off is good practice to avoid later accidental plotting on same axes
hold off
% Draw from the buffer
drawnow
end
you can save(if you want) this animation with getFrame function and play it with movie function
and another function may helps you is comet.
I want to plot an x-axis (bot) that corresponds to values with another x-axis (top), against some data. I want the top and bot axis to refer to the same data point. The following code demonstrates my problem
clc; clear all;
botXaxis = [2.54 1.61 1.00 0.61 0.37];
topXaxis = [159283 97232 59354 36232 22117];
data = [10 10 10 10 10];
hplot = plot(botXaxis,data);
set(hplot,'Linestyle','none','Marker','o');
ax1 = gca;
ax1.XScale = 'log';
ax1.XTick = fliplr(botXaxis);
ax1.XLim = [min(botXaxis) max(botXaxis)];
ax1.XTickLabel = fliplr(botXaxis);
hold on
plot1 = plot([botXaxis(3) botXaxis(3)],get(ax1,'YLim'),'--','color',[0 0 0]);
ax1_pos = ax1.Position;
ax2 = axes('Position',ax1_pos,'XAxisLocation','top','YAxisLocation','right','Color','none');
ax2.XScale = 'log';
set(ax2, 'XTickMode', 'manual');
ax2.XLim = [min(topXaxis) max(topXaxis)];
ax2.XTickMode = 'auto';
ax2.XTick = fliplr(topXaxis);
hold on
plot1 = plot([topXaxis(3) topXaxis(3)],get(ax1,'YLim'),'-','color',[0 0 0]);
% Fix double tick marks
set(ax1,'box','off');
If you run it this plot appears:
I have drawn the straight lines to see if the data lines up correctly. As you can see they do not. I am wondering if there is a way to fix this? The values for data should line up with both topXaxis and botXaxis.
Thanks
I am currently working on a project simulating the movement of two spacecraft and a moon (Phobos) around Mars. A MATLAB tool called SPICE gives me an array with the x, y and z distances and I have used these to plot the orbit which works fine. Now I want to get markers for each of the spacecraft and Phobos to see when they flyby each other. I got the markers working but not at the same time, they run after each other. I found an example on youtube so it must be possible but he has not released the code how to do it (https://www.youtube.com/watch?v=nArR2P0o4r4).
This is the code I have:
a = position_MEX_Mars(1,:);
b = position_MEX_Mars(2,:);
c = position_MEX_Mars(3,:);
k = position_MAVEN_Mars(1,:);
l = position_MAVEN_Mars(2,:);
m = position_MAVEN_Mars(3,:);
x = position_Phobos_Mars(1,:);
y = position_Phobos_Mars(2,:);
z = position_Phobos_Mars(3,:);
ah = axes;
set(ah,'XLim',[min(x) max(x)],'YLim',[min(y) max(y)],...
'ZLim',[min(z) max(z)]);
plot3(0,0,0,'ro-',x,y,z,a,b,c,k,l,m);
grid on;
hold on;
hpoint = line('XData', 0,'YData', 0,'ZData', 0,'Color','black','Marker',...
'o','MarkerSize',10);
ht = hgtransform('parent',ah);
set(hpoint,'Parent',ht);
for i =2:length(x)
trans = makehgtform('translate',[x(i) y(i) z(i)]);
set(ht,'Matrix',trans);
pause(0.001);
end
This will run a nice animated plot of the trajectory of Phobos in time but only Phobos and not simultaneous with MEX and MAVEN (spacecraft from ESA and NASA).
I tried this but does not work:
a = position_MEX_Mars(1,:);
b = position_MEX_Mars(2,:);
c = position_MEX_Mars(3,:);
k = position_MAVEN_Mars(1,:);
l = position_MAVEN_Mars(2,:);
m = position_MAVEN_Mars(3,:);
x = position_Phobos_Mars(1,:);
y = position_Phobos_Mars(2,:);
z = position_Phobos_Mars(3,:);
ah = axes;
set(ah,'XLim',[min(x) max(x)],'YLim',[min(y) max(y)],...
'ZLim',[min(z) max(z)]);
plot3(0,0,0,'ro-',x,y,z,a,b,c,k,l,m);
grid on;
hold on;
hpoint = line('XData', 0,'YData', 0,'ZData', 0,'Color','black','Marker',...
'o','MarkerSize',10);
ht = hgtransform('parent',ah);
set(hpoint,'Parent',ht);
for i =2:length(x)
trans1 = makehgtform('translate',[x(i) y(i) z(i)]);
set(ht,'Matrix',trans1);
trans2 = makehgtform('translate',[a(i) b(i) c(i)]);
set(ht,'Matrix',trans2);
pause(0.001);
end
I also tried merging the arrays so that it plots them each one step after each other but that makes the animation not smooth and is not satisfying for the project.
a = position_MEX_Mars(1,:);
b = position_MEX_Mars(2,:);
c = position_MEX_Mars(3,:);
k = position_MAVEN_Mars(1,:);
l = position_MAVEN_Mars(2,:);
m = position_MAVEN_Mars(3,:);
x = position_Phobos_Mars(1,:);
y = position_Phobos_Mars(2,:);
z = position_Phobos_Mars(3,:);
tempx = [position_MEX_Mars(1,:); position_Phobos_Mars(1,:); position_MAVEN_Mars(1,:)];
xt = tempx(:);
tempy = [position_MEX_Mars(2,:); position_Phobos_Mars(2,:); position_MAVEN_Mars(2,:)];
yt = tempy(:);
tempz = [position_MEX_Mars(3,:); position_Phobos_Mars(3,:); position_MAVEN_Mars(3,:)];
zt = tempz(:);
ah = axes;
set(ah,'XLim',[min(x) max(x)],'YLim',[min(y) max(y)],...
'ZLim',[min(z) max(z)]);
plot3(0,0,0,'ro-',x,y,z,a,b,c,k,l,m);
grid on;
hold on;
hpoint = line('XData', 0,'YData', 0,'ZData', 0,'Color','black','Marker',...
'o','MarkerSize',10);
ht = hgtransform('parent',ah);
set(hpoint,'Parent',ht);
for i =2:length(x)
trans = makehgtform('translate',[xt(i) yt(i) zt(i)]);
set(ht,'Matrix',trans);
pause(0.001);
end
I think I am close but I seem to be missing something and my knowledge of MATLAB is not that great yet. I hope you can help me out.
Cheers Jeroen
Here's a simplified (and not physically correct) example that could perhaps be useful:
t = linspace(0,2,1000); %// time parameter
x1 = 10*cos(2*pi*t+1);
y1 = 5*sin(2*pi*t+1); %// trajectory of object 1
x2 = 2*cos(6*pi*t-2);
y2 = 3*sin(6*pi*t-2); %// trajectory of object 1
plot(x1,y1,'color',[.5 .5 .5]); %// plot trajectory of object 1
hold on
plot(x2,y2,'color',[.5 .5 .5]); %// plot trajectory of object 2
h1 = plot(x1(1),y1(1),'ro'); %// plot initial position of object 1
h2 = plot(x2(1),y2(1),'b*'); %// plot initial position of object 2
axis([-12 12 -12 12]) %// freeze axis size
grid on
for n = 1:numel(t)
set(h1, 'XData', x1(n), 'YData', y1(n)); %// update position of object 2
set(h2, 'XData', x2(n), 'YData', y2(n)); %// update position of object 2
drawnow %// refresh figure
end
The thing that you tries to do is not really as easy as you think. The main issue is that you need to update everything at the same time. This have been implemented in several ways during the years. One way to do this is by using a so called a double buffer.
This means that you have two "surfaces" to paint on. In matlab this is translated to 2 axes (or 2 figures maybe). However, you do only have one axes visible at the same time. This means that you will have time to paint everything on the "hidden surface" before displaying the content. When you are done with everything you need you just switch which surface being visible.
It is possible that this can be done in a simpler way, but I am not familiar with the hgtransfrom functions in matlab.
EDIT
This is an example how it can be done
function test()
fig = figure;
ax1 = axes;
plot(1:10);
ax2 = axes;
plot(1:10,'r');
setVisibility(ax2,'off');
pause(1);
for k = 1:5
setVisibility(ax2,'on');
setVisibility(ax1,'off');
pause(1);
setVisibility(ax1,'on');
setVisibility(ax2,'off');
pause(1);
end
function setVisibility(ax, visibility)
set(ax, 'visible', visibility)
set(findall(ax), 'visible', visibility)