% Class 4 - Last of Matlab Bootcamp
% Coded by NFR on 9.5.2109
% Topics today
% 1) More for/while loop practice
% 2) Plotting
% 3) Functions (variables, structure)
% 4) Class example
%
% Example of loops
%
% For loop to calculate pi from Leibniz series
% 
clc
close all % This closes previous figure windows
n = 100000; % # of iterations
val = 0;
for i = 1:n
    d = i*2-1;
    if mod(i,2) == 0 % even
        val = val - 1/d;
    else % odd values
        val = val + 1/d;
    end
end
fprintf('Estimated value of pi is %.5f\n',val*4)
% Same formula, but use while loop to exit
% based on a tolerance criteria
tol = 0.0000001; %
% Remember this is the difference between
% the last calculated estimate and the current estimate
tolcheck = 1; % intialize check value
count = 1;
val = 0;
while tolcheck > tol
    d = count*2-1;
    oldval = val;
    if mod(count,2) == 0 % even
        val = val - 1/d;
    else % odd values
        val = val + 1/d;
    end  
    count = count + 1;
    tolcheck = abs(oldval-val);
end
count
pi_e = val*4
% PART II - Plotting
% Import data from the saved excelfiles
WD = readmatrix('weather.xlsx');
PD = readmatrix('IA pop data.xlsx');
% Simple plot of avg vs. day
X = WD(3:end,1); % days
Y = WD(3:end,3); % avg temp
plot(X,Y,'+k')
xlabel('Days in May 2017')
ylabel(['Avg Temperature (',char(176),'C)'])
title('This is my plot!')
text(7,50,'HELLO!')
hold on % this specifies, next plot command
% goes on top of the current plot
plot(15,50,'ob')
hold off % turn off hold when plot is complete
% 
figure % this opens a new figure window for next plot
% Plot the population data
X = PD(2:end,1); % years
Y = PD(2:end,2); % population
plot(X,Y,'o:')
xlabel('Years')
ylabel('Population in IA')
%
figure
semilogy(X,Y,'o:')
xlabel('Years')
ylabel('Population in IA')
% How to use error bars
% weather data, error bars will show high and low data
X = WD(3:end,1); % days
Y = WD(3:end,3); % avg temp
lowvec = WD(3:end,2); % low temp
highvec = WD(3:end,4); % high temps
figure
errorbar(X,Y,Y-lowvec,highvec-Y)
xlabel('Days in May 2017')
ylabel(['Avg Temperature (',char(176),'C)'])
saveas(gcf,'Plot1.jpg')
% Let's say you want multiple plots on the same screen
% Use subplots
figure
subplot(1,3,1)
plot(X,Y)
title('Avg. temp')
subplot(1,3,2)
plot(X,lowvec,'k:o')
title('Low temp')
subplot(1,3,3)
plot(X,highvec)
title('High temp')
% Discrete data (bar chart)
% Dr. Reuel will post a couple examples
% of bar charts
DS = readmatrix('skillsurvey.xlsx');
set(gca,'YTickLabel',{'A' 'B' 'C' 'D' 'E'})
figure
bar(DS(:,4))
% 3D data set
figure
Zdata = readmatrix('elevation.csv');
%contourf(Zdata)
%surface(Zdata)
%
% A few important reminders about functions
% 1) You can create a separate file as the function
% 2) You can also write a function 
%    as a 'local function' 
%    this is typically at end of code
% 3) You can also define an anonymous function
%    This is defined much like a variable
%    in the main block of code

% Example of an anonymous function
afunc1 = @(x) sin(x)+2-3;
output1 = afunc1(2);
figure
fplot(afunc1,[0 5])