MATLAB Part 4 - Plotting

f=@(x) 1./x;                           % y values of what is being plotted

Note on Continuity
The function f is continuous with inf inite domain
computers need discrete information

x=linspace(1,100,10)                   % x values of what is being plotted
y=f(x)
figure(1)                              % Initiates figure 1
plot(x,y)

x=linspace(1,100,1000)                 % x values of what is being plotted
y=f(x);                                % y values of what is being plotted
plot(x,y)

plot(x,y,'+')                          % Plot unconnected plus siges
plot(x,y,':')                          % Plot connected dots
plot(x,y,'.')                          % Plot continuous line
plot(x,y,'k')                          % Plot black continuous line
plot(x,y,'r')                          % Plot red continuous line
plot(x,y,'r.')                         % Plot red points
plot(x,y,[.3 .3 .3]                    % RGB values
help plot                              % All properties

plot(x,y,'r.','MarkerSize',10)         % Change size of markers
plot(x,y,'r','LineWidth',10)           % Change size of line
plot(x,y,'ro','MarkerEdgeColor','b')   % Change collor of marker border

title('1/x')                           % Create title
xlabel('this is x')                    % Label x axis
ylabel('this is y')                    % Label y axis
legend('Responses')                    % Add legend with label 'Responses'

xlim([0 40])                           % Set x axis limits
ylim([0 .4])                           % Set y axis limits
ylim('auto')
xlim('auto')

g=@(x) 1./(x.^2)
z=g(x)
plot(x,z)                              % Erases what we've done
plot(x,y,'ro','MarkerEdgeColor','b')
hold on                                % "Don't erase"
plot(x,z)
legend('Responses1','Responses2')      % Add legend with 2 labels
hold off

Figure 2 - Subplots

figure(2)
x=-2:0.25:2;
y1=exp(x)
y2=log(x)
y3=abs(x)
y4=x.^2

subplot(2,3,1)
plot(x,y1)
subplot(2,3,3)
plot(x,y2)
subplot(2,3,2)
plot(x,y4)
subplot(2,3,4)
plot(x,y3)

subplot(2,1,2)
plot(x,y3)

subplot(2,3,2)
ylim([-3 1])

Figure 3 - 3D

h=@(x,y) x.*exp(-x.^2-y.^2)  % Same discretization problm before
x=linspace(-2,2,100);        % x values
y=linspace(-2,2,100);        % y values
z=h(x,y)
imagesc(z)                   % This doesn't look right...
size(z)                      % Actually visualizing accross the diagonal

[X,Y]=meshgrid(x,y);         % This distributes x and y
imagesc(X)
imagesc(Y)

figure(3)
z=h(X,Y)
size(z)
imagesc(z)                   % Third dimension is represented by color
colorbar
caxis([-.2, .2])
colormap winter
help graph3d

close                        % Close current figure
surf(z)                      % Third dimension is represented by color and space
                             % If resolution is too high, you can't see the surface
surf(z,'EdgeColor','none')
surf(z,'EdgeColor','none','FaceAlpha',.8)

load('spine')                 % Loads in a variable X
size(X)                       % X is a matrix...
imagesc(X)                    % But an image!
colormap gray
axis image                    % Fix pixel dimensions

Plot on Images
You can plot on top of a figure
First notice that the y axis is upside down
Lets try and plot in the lower left corner

hold on
plot(300,80,'.r','MarkerSize',50)

imagesc(X)
plot(80,300,'.r','MarkerSize',50)
colormap gray

Figure 4 - histogram

figure(4)
A=randn(1000,1)          % Normally distributed random numbers
histogram(A)             % Histogram, automatically setting the number of bins
histogram(A,10)          % Set number of bins to 10
help histogram

Figure 5 - bar

figure(5)
counts=[countsA; countsB]
bar(ctrsA,counts')
bar(ctrsA,counts',1)
bar(ctrsA,counts','stacked')
close all                 % Close all figures

figure(5)
plot(ctrsA,countsB,'k')
hold on
plot(ctrsB,countsB,'r')
close all

Figure 1 - 2D

Figure 2 - Subplots

Figure 3 - 3D

Figure 4 - histogram

Figure 5 - bar