%% Matlab Graphics

% This m-file contain the code used in Session 3 of the course  "Matlab for
% Research" run for PhD students and postdocs in the faculty of Science at
% the University of East Anglia. 
%
% This file, and the accompanying course notes, are available at
% http://researchpages.net/people/colin-goldblatt/teaching/matlab/
%
% Colin Goldblatt, 21/10/2007

%% Line plots

figure

x = [-20:0.01:20];
y = sin(x);
z = cos(x);

plot(x,y,'r',x,z,'g')

xlabel('x')
ylabel('sin(x) and cos(x)')
title('A simple graph')

legend('sin(x)','cos(x)')

print -dpdf graph2.pdf

%%

figure

h1 = plot(x,y,'r')
hold on
h2 = plot(x,z,'g')

set(h1,'color',[ 1 0.5 0],'linewidth',4)

set(gca,'xlim',[-pi pi],...
        'xtick',[-pi:pi/2:pi],...
        'xticklabel',{'-pi','-pi/2','0','pi/2','pi'})
    
xlabel('-\pi \leq \Theta \leq \pi')

width = 12;
height = 10;
set(gcf,'paperunits','centimeters',...
    'PaperSize',[width height],...
    'PaperPosition',[0 0 width height])

print -dpdf graph2.pdf

%% some more plots

figure

a = [1:1:10]
b = a.^2;
plot(a,b,'go--')

hold on

% annotaion
text(2,20,'hello!','color','b')

h5 = text(2,40,'hello!');
set(h5,'color','m')

% add a filled shape
c1 = [4 4 5 5];
c2 = [10 30 30 10];
h3 = fill(c1,c2,'c');

% add another shape and make it transparent with no line
d1 = [7 7 8 8];
d2 = [50 60 60 50];
h4 = fill(d1,d2,'r','linestyle','none');
alpha(h4,0.3)

%% Subplots (1)

a = [0:1:100];
b = randn(size(a));

figure

subplot(2,2,1)
plot(a,b,'r-')

subplot(2,2,2)
stem(a,b)

subplot(2,2,3:4)
scatter(a,b,40,abs(b),'filled')

%% Subplots (2)

% this produces a 5 x 2 set of subplots which looked right for my thesis
sleftoffset = 0.10;
srightoffset = 0.04;
sbottomoffset = 0.05;
stopoffset = 0.023;
swidth = 0.5 - sleftoffset - srightoffset;
sheight = 0.2 - sbottomoffset - stopoffset;
vpos = [0.8 0.6 0.4 0.2 0];
hpos = [0 0.5];

a = [0:1:100];

figure

for ih = 1:length(hpos)
    for iv = 1:length(vpos)
        subplot('Position',...
            [hpos(ih)+sleftoffset vpos(iv)+sbottomoffset swidth sheight])
        plot(a,randn(size(a)),'r-')
        xlabel('Time')
        ylabel('Made up data')
    end
end

% add labels to the plot
% this uses another axes overlaid on the figure
h = axes('Position',[0 0 1 1],'Visible','off');
set(gcf,'CurrentAxes',h)
set(h,...
    'DefaultTextVerticalAlignment','Cap',...
    'DefaultTextHorizontalAlignment','left',...
    'DefaultTextFontSize',12,...
    'DefaultTextFontWeight','bold');
hold on
tposv = [1 0.8 0.6 0.4 0.2];
tposh = [0 0.5];
lab = ['ab';'cd';'ef';'gh';'ij'];
for vv = 1:length(tposv)
    for hh=1:2
        text(tposh(hh),tposv(vv),lab(vv,hh))
    end
end

% setup the page size and print the graph
width = 12.6;
height = 20;
set(gcf,'paperunits','centimeters',...
    'PaperSize',[width height],...
    'PaperPosition',[0 0 width height])

print -dpdf graph3.pdf

%% Regression

% example of fitting a line to a curve

a = [0:0.1:10];
b = 3*a+2 + randn(size(a));

figure
plot(a,b,'rx')
hold on

p=polyfit(a,b,1);
plot(a,polyval(p,a),'k-')
text(3,5,['y = ',num2str(p(1)),'x + ',num2str(p(2))])


%% Plotting matrix data - caution (1)

A = magic(3)

figure
pcolor(A)
shading flat


B = NaN*ones(4,4)
B(1:3,1:3) = A

figure
pcolor(B)
shading flat


figure
imagesc(A)
axis xy

%% Plotting matrix data - caution (2)

x = 1:10;
y = 1:20;
Z = x'*y;

figure
pcolor(x,y,Z')
figure
%pcolor(y,x,Z')
figure
imagesc(x,y,Z')
figure
imagesc(y,x,Z')
figure
imagesc(1:1:3,50:-10:-250,Z')


%% Plotting matrix data - caution (3)

figure
pcolor(A)
shading interp

figure
contourf(A)
shading flat

%% plotting matricies - pretty pictures

A = peaks(50);

figure
imagesc(A)
axis xy

figure
contourf(A)
shading flat

figure
contourf(A,50)
shading flat

colorbar('southoutside')

caxis([-2 2])

colormap gray

figure
surf(A)