Lab 1: Introduction to Matlab
Engr 451
Zachary Armendariz
and
Luke Jocson
Date Report Submitted: Feb. 10, 2017
ENGR 451 - Lab 1
Matlab tutorial
clear
x = sequence([1 2 3 4 5], 1);
y = sequence([5 3 1 -1 3 -2 2 3], -1);
% test plus
test_lab1('plus(x, y)')
test_lab1('plus(y, x)')
test_lab1('plus(1, x)')
test_lab1('plus(x, 1)')
y = sequence([5 3 1 0 3 -2 2 3], -4);
test_lab1('plus(x, y)')
test_lab1('plus(y, x)')
% test minustract
test_lab1('minus(x, y)')
test_lab1('minus(y, x)')
test_lab1('minus(1, x)')
test_lab1('minus(x, 1)')
% test timesiplication
test_lab1('times(x, y)')
test_lab1('times(3, x)')
test_lab1('times(x, 3)')
% test flip
test_lab1('flip(x)')
% test shift
test_lab1('shift(y, 2)')
%combinations
test_lab1('flip(minus(shift(plus(x, 2), 4), y))')
test_lab1('plus(flip(plus(x, y)), shift(y, -5))')
test_lab1('minus(plus(times(shift(flip(x), 4), shift(y, 3)), flip(y)), x)')
% test stem
set(clf, 'Position', [200 200 400 200])
stem(flip(2+(x-shift(y, -4).*y-3)))
title('y[n]');
% Program Listings
fprintf('\n\n')
disp('--- sequence.m --------------------------------')
type sequence
plus(x, y): sequence O.K.
plus(y, x): sequence O.K.
plus(1, x): sequence O.K.
plus(x, 1): sequence O.K.
plus(x, y): sequence O.K.
plus(y, x): sequence O.K.
minus(x, y): sequence O.K.
minus(y, x): sequence O.K.
minus(1, x): sequence O.K.
minus(x, 1): sequence O.K.
times(x, y): sequence O.K.
times(3, x): sequence O.K.
times(x, 3): sequence O.K.
flip(x): sequence O.K.
shift(y, 2): sequence O.K.
flip(minus(shift(plus(x, 2), 4), y)): sequence O.K.
plus(flip(plus(x, y)), shift(y, -5)): sequence O.K.
minus(plus(times(shift(flip(x), 4), shift(y, 3)), flip(y)), x): sequence O.K.
--- sequence.m --------------------------------
%Lab 1
%Zachary Armendariz
%Luke Jocson
%The purpose of this lab is to create the code to perform different
%functions on sequences with Matlab.
classdef sequence
properties %This first section of code was given
data %and identifies a sequence as a new
offset %Matlab structure.
end
methods
function s = sequence(data, offset)
s.data = data;
s.offset = offset;
end
function display(s) %The display portion of the code is
var = inputname(1); %only there to make the output of
if (isempty(var)) %sequence data more compact and
disp('ans ='); %readable.
else
disp([var '=']);
end
switch length(s.data)
case 0
disp(' data: []')
case 1
disp([' data: ', num2str(s.data)])
otherwise
disp([' data: [' num2str(s.data) ']'])
end
disp([' offset: ' num2str(s.offset)])
end
function y = flip(x)
% FLIP Flip a Matlab sequence structure, x, so y = x[-n]
z = x.data; %Declare a new array.
z(1:length(x.data)) = x.data(end : -1 : 1);
%This code stores the sequence into the array
%in the opposite order.
y = sequence(z, -(x.offset + length(x.data) - 1));
%The sequence is reconstructed with a new
end %offset based on the length and offset of
%the original sequence.
function y = shift(x, n0)
% SHIFT Shift a Matlab sequence structure, x, by integer amount n0 so that
y[n] = x[n - n0]
nf = x.offset + n0; %This finction simply adds a shift value
y = sequence(x.data, nf); %to the offset and reconstructs the
end %sequence.
function y = trim(x) %This function was designed to
indices = find(x.data); %remove zeros from the upper and
x.data(1:indices(1)-1) = []; %lower bounds of a sequence.
x.data(indices(end) - indices(1) + 2 : end) = [];
offset = x.offset + indices(1) - 1;
y = sequence(x.data, offset);
end
function z = plus(x, y)
% PLUS Add x and y. Either x and y will both be sequence structures, or
one of them may be a number.
if(isa(x, 'sequence') & isa(y, 'sequence'))
offset = 0; %Before two arrays can be added
lpad = x.offset - y.offset; %they have to be padded with zeros
%so they share the same length
%and offset.
rpad = length(y.data) + y.offset - length(x.data) - x.offset;
seq1 = [zeros(1, lpad) x.data zeros(1, rpad)];
seq2 = [zeros(1, -lpad) y.data zeros(1, -rpad)];
data = seq1 + seq2; %the arrays can be added easily when
if(x.offset < y.offset)%they are the same size.
offset = x.offset;
else %Next the larger offset has to be
offset = y.offset; %found to be used in forming the
end %resultant sequence.
if (sum(data) == 0) == length(data)
z = sequence(0, 0); %Finally the sequence is trimmed
else %and reconstructed. The if statement
%is for the unlikely case that the
z = trim(sequence(data, offset));%resultant sequence is
end %null.
elseif(isa(x, 'float'))
data = y.data + x; %If one of the inputs is a scalar instead
%of a sequence a different code is
%used.
if (sum(data) == 0) == length(data)
z = sequence(0, 0); %This code is very simple since
else %the scalar can just be added to
z = trim(sequence(data, y.offset));%all the elements
end %of the data portion of the sequence.
else
data = x.data + y;
if (sum(data) == 0) == length(data)
z = sequence(0, 0);
else
z = trim(sequence(data, x.offset));
end
end
end
function z = minus(x, y)
% MINUS Subtract x and y. Either x and y will both be sequence structures,
or one of them may be a number.
% The minus function is the same as the plus function, but the
% second element in the array needs to be inverted.
if(isa(x, 'sequence') & isa(y, 'sequence'))
yneg = y.data .* -1;
negseq = sequence(yneg, y.offset);
z = x + negseq;
elseif(isa(x, 'float'))
data = -1 .* y.data + x;
if (sum(data) == 0) == length(data)
z = sequence(0, 0);
else
z = trim(sequence(data, y.offset));
end
else
data = x.data - y;
if (sum(data) == 0) == length(data)
z = sequence(0, 0);
else
z = trim(sequence(data, x.offset));
end
end
end
function z = times(x, y)
% TIMES Multiply x and y (i.e. .*) Either x and y will both be sequence
structures, or one of them may be a number.
% Multiplying is again very similar to the plus function, but
% using the .* operator.
if(isa(x, 'sequence') & isa(y, 'sequence'))
offset = 0;
lpad = x.offset - y.offset;
rpad = length(y.data) + y.offset - length(x.data) - x.offset;
seq1 = [zeros(1, lpad) x.data zeros(1, rpad)];
seq2 = [zeros(1, -lpad) y.data zeros(1, -rpad)];
data = seq1 .* seq2;
if(x.offset < y.offset)
offset = x.offset;
else
offset = y.offset;
end
if (sum(data) == 0)
z = sequence(0, 0);
else
z = trim(sequence(data, offset));
end
elseif(isa(x, 'float'))
data = y.data .* x;
if (sum(data) == 0) == length(data)
z = sequence(0, 0);
else
z = trim(sequence(data, y.offset));
end
else
data = x.data .* y;
if (sum(data) == 0) == length(data)
z = sequence(0, 0);
else
z = trim(sequence(data, x.offset));
end
end
end
function stem(x)
% STEM Display a Matlab sequence, x, using a stem plot.
% Finally it is important to create a function for plotting the
% results. This function simply creates the appropriate
% abscissa using the ofset of the sequence.
m = x.offset : x.offset + length(x.data) - 1 ;
stem(m, x.data, 'filled');
axis tight
xlim([(m(1) - 1) (m(end)+1)]);
ylim([(min(x.data) - 1) (max(x.data) + 1)]);
end
end
end
Published with MATLAB® R2016a
