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How to crate only 5 plots out of the 20000 iterations?

Asked by Mina Mansour on 13 Aug 2019
Latest activity Answered by the cyclist
on 13 Aug 2019
This is my code and i am trying to plot using imagesc to just show a plot at 0, 5, 10, 15, and 20s only althought there are so many iterations but they all are useless to me, how can I do that efficently and for all number of iterations?
% Five Point Stencils:
% Common constants:
a = 1; b = 1; gamma = 1; D = 3; nROWS = 150; nCOLS = 100; stencil = 5;
% The h spacing is a constant:
h = 1;
% Initial and final time conditions.
t0 = 0; tf = 20; dt = 1e-3;
% time vector and time iteration size.
t = t0:dt:tf;
mt = length(t);
% phi is a random nROWS x nCOLS matrix that contains only 1 & -1:
phi = floor(randsrc(nROWS,nCOLS,[-1,1 ; 0.5,0.5]));
% newphi matirx:
newphi = zeros(nROWS,nCOLS);
% Plotting initial:
figure (1)
imagesc(phi)
% Material A is 1 and Material B is -1
colorbar
caxis([-1 1])
title(['1st Order Euler Field Distribution at stencil = ' num2str(stencil) ', dt = ' num2str(dt) 's, and t = ' num2str(t0) 's.'],'FontSize',18)
set(gca,'LineWidth',1,'FontSize',8)
axis equal
for k = 1:mt-1
% Eqn 4:
v1 = Laplacian_2D(phi,h,stencil);
v2 = (b^4 * phi.^3 - a * b^2 * phi) - gamma * v1;
v3 = D * Laplacian_2D(v2,h,stencil);
newphi = phi + dt * v3;
phi = newphi;
if k == 5000
% Plotting at 5 seconds:
figure (2)
imagesc(phi)
colorbar
caxis([-1 1])
title(['1st Order Euler Field Distribution at stencil = ' num2str(stencil) ', dt = ' num2str(dt) 's, and t = ' num2str(5) 's.'],'FontSize',18)
set(gca,'LineWidth',1,'FontSize',8)
axis equal
elseif k == 10000
% Plotting at 10 seconds:
figure (3)
imagesc(phi)
colorbar
caxis([-1 1])
title(['1st Order Euler Field Distribution at stencil = ' num2str(stencil) ', dt = ' num2str(dt) 's, and t = ' num2str(10) 's.'],'FontSize',18)
set(gca,'LineWidth',1,'FontSize',8)
axis equal
elseif k == 15000
% Plotting at 15 seconds:
figure (4)
imagesc(phi)
colorbar
caxis([-1 1])
title(['1st Order Euler Field Distribution at stencil = ' num2str(stencil) ', dt = ' num2str(dt) 's, and t = ' num2str(15) 's.'],'FontSize',18)
set(gca,'LineWidth',1,'FontSize',8)
axis equal
elseif k == 20000
% Plotting at 20 seconds:
figure (5)
imagesc(phi)
colorbar
caxis([-1 1])
title(['1st Order Euler Field Distribution at stencil = ' num2str(stencil) ', dt = ' num2str(dt) 's, and t = ' num2str(20) 's.'],'FontSize',18)
set(gca,'LineWidth',1,'FontSize',8)
axis equal
end
end

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R2019a

1 Answer

Answer by the cyclist
on 13 Aug 2019
 Accepted Answer

Use
if mod(k,5000)==0
...
end
and just
figure
or
figure(k/5000)
Just using the figure command (without any argument) will open a new figure, with the next consecutive available number.

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