Matlab continue graph for second loop - matlab

Question

%free fall of a ball
clc
clear all
close all
v0=5; % initial velocity up
g=9.8; %free fall acceleration
v1=(0.7/0.9)*v0
% time of fly
tup=v0/9;
nsteps=10; %number of frames
dt=tup/nsteps; %time step
Hmax=v0*tup+(-g)*tup*tup/2; % maximum altitude
altitude(1:nsteps+1)=0; %define array for position Y
time=0:dt:tup;% define time array
%initilaise plot
figure(1)
axis([0,2*tup,0,2*Hmax]);
hold on
% loop
for i=1:nsteps
altitude(i)=v0*time(i)+(-g)*time(i)*time(i);
plot(time(i),altitude(i), 'ro')
grid on;
M(i)=getframe;
end
%loop bouncing
for i=1:nsteps
altitude(i)=v1*time(i)+(-g)*time(i)*time(i);
plot(time(i),altitude(i), 'ro')
grid on;
M(i)=getframe;
end
%make movie
movie(M);
movie2avi(M, 'C:\Users\Mehmet\Desktop\avi\mm','compression','none');
%extra plots
figure(2)
plot(time(1:nsteps),altitude(1:nsteps))
figure(3)
plot(time(1:nsteps),altitude(1:nsteps),'ro')
We have this ball bouncing simulation. What we want to do is, to continue loop 2 after loop 1 in graph.So, it will be continious bouncing simulation.2 bouncings are shown from 1:10 steps but we want second loop to be shown after 10 steps.

Answer 1

There are a couple of approaches, depending upon what effect you're going for. The simplest is to simply add hold on as a separate command after each of your plot commands. This will keep accumulating new lines/dots without erasing the old ones. To stop this effect, add a hold off command. The next plot command will then erase everything and plot on a clean graph.
Alternatively, if you only want to show a fixed number of the previous steps (and not all of them, as the hold on will do), you'll have to explicitly hold onto the previous values. Something like this:
% loop
max_history = 10; %plot this many symbols
for i=1:nsteps
altitude(i)=v0*time(i)+(-g)*time(i)*time(i);
%get the historical and current data points to plot
start_ind = i-max_history+1; %here's the oldest point that you'd like
start_ind = max([start_ind, 1]) %but you can't plot negative indices
inds = [start_ind:i]; %here are the ones to plot
%update the plot
plot(time(inds),altitude(inds), 'ro');
grid on;
%you might need a "drawnow" here
M(i)=getframe;
end
Copy this same idea into your other for loops and you should be good-to-go!