for-end loop with increment and movie

My code plots a route taken based on random numbers and takes frames at intervals of 1000 steps. However the total number of steps won't always be divisible by 1000, is there a way of always plotting the final frame in the set?

here's my code at the moment

for j=1:1000:k

M((j-1)/1000+1) = getframe;

plot(x(1:(j+1)),y(1:(j+1)))

axis equal

    if x(j+1)==H1 && y(j+1)==H2
      break
    end
  end

hold off
movie(M)

Answer 1

[Sean de Wolski]

First, make sure to use drawnow to refresh the graphics queue between loop iterations.

Second, use the for-loop variable as the index and generate the other values from it (i.e. inverse to what you've done). Then run it from 1-however_many

Third, use min() to saturate the variable at the maximum ends of things so you don't get out of dimension errors. e.g. if j = 100001 and the max you have is 100000, use min(j,10000) so you don't over step the number of elements.

[Wendy]

Thanks for your help.

We'd decided against drawnow because it seemed quicker to generate all the values first and then plot them all at once.

I don't know what you mean by the index, we've been taught some basic commands but nothing has really been explained to us. However if you mean to use the values of j to create the values of k, there's another for loop which creates those.

Here's the full code if that makes more sense;

clear all

H1 = input('Please enter a co-ordinate for the drunk mans Home in the x-direction');

H2 = input('Please enter a co-ordinate for the drunk mans Home in the y-direction');

while H1==0 && H2==0

disp('The pub is not the drunk mans Home')

H1 = input('Please enter a co-ordinate for the drunk mans Home in the x-direction');

H2 = input('Please enter a co-ordinate for the drunk mans Home in the y-direction');

end

N = input('Please enter a value between 10 and 5,000,000 for the number of steps');

while N<10||N>5000000

disp('Sorry, you did not enter a valid number please try again')

N = input('Please enter a value between 10 and 5,000,000 for the number of steps');

end

x = 0;

y = 0;

x = zeros(1,N);

y = zeros(1,N);

for k=1:N

J = rand;

if J<0.25;

x(k+1)=x(k)+1;

y(k+1)=y(k);

elseif J>=0.25 && J<0.5;

x(k+1)=x(k);

y(k+1)=y(k)+1;

elseif J>=0.5 && J<0.75;

x(k+1)=x(k)-1;

y(k+1)=y(k);

else

x(k+1)=x(k);

y(k+1)=y(k)-1;

end

if x(k+1)==H1 && y(k+1)==H2

steps = k+1;

break

end

end

if k<N

disp ('The Drunk man arrived home')

else disp('The Drunk man does not arrive home')

end

disp('Number of Steps taken is')

disp(k)

plot(H1,H2,'mp')

text(H1,H2,'\leftarrowHome');

hold on

plot(0,0,'bs')

text(0,0,'\leftarrowEchos');

hold on

for j=1:1000:k

M((j-1)/1000+1) = getframe;

plot(x(1:(j+1)),y(1:(j+1)))

axis equal

if x(j+1)==H1 && y(j+1)==H2

break

end

end

hold off

movie(M)