%Your first and last name:

%Your 810/811 number:

%Lab 04

%Your task for this lab assignment is to correctly implement

%the matrixmultiply function and the dotproduct function

%based on their comments, pseudocode, provided code, and examples.

%Assume arg1 is the name of an input file in the current working

%directory that contains the elements of the n by m matrix A.

%Assume arg2 is the name of an input file in the current working

%directory that contains the elements of the m by r matrix B.

%Assume matricies A and B are compatible for matrix multiplication.

%Since the matrixmultiply function calls the dotproduct function,

%the dotproduct function should be implemented first.

%Do not use any built in functions or operators that automatically

%compute the product (multiplication) of matricies or the dot product.

function [P] = matrixmultiply(arg1, arg2)

A = readmatrix(arg1); %initialize A from file

B = readmatrix(arg2); %initialize B from file

%initialize n to the number of rows in A

n = size(A, 1);

%initialize m to the number of columns in A

m = size(A, 2);

%initialize r to the number of columns in B

r = size(B, 2);

if( m ~= size(B, 1) )

fprintf("Error: Multiplication is undefined for A and B. Goodbye. ");

return;

end

% use Matlab's display function to display A as shown in the examples

disp('A =');

disp(A);

% use Matlab's display function to display B as shown in the examples

disp('B =');

disp(B);

% print the following as shown in the examples

fprintf("Assume AB = P. ");

fprintf("Dot product(s) for calculating P: ");

% initialize P to an n by r matrix filled with zeros

% by using Matlab's zeros function

P = zeros(n,r);

%Pseudocode for computing P.

% for each row i in P(i, j)

for i=1:n

% for each column j in P(i, j)

for j=1:r

% assign rowA to the ith row in A

rowA = A(i, :);

% assign colB to the jth row in B

colB = B(:, j)

% using the dotproduct function that you implented,

% assign P(i, j) to the dotproduct of rowA and colB

% print the dot product as shown in the examples by using the code below

% fprintf("P(%i, %i) = ", i, j);

% printvectors(rowA, colB);

% fprintf(" = %.4f ", P(i, j));

% use Matlab's display function to display P as shown in the examples

end

%Return d, the dot product of vectors x and y.

%Use loop(s), variable(s), and simple arithmetic operator(s) to

%to implement this function. You may use the size function.

%Do not use any built in functions or operators that calculate

%the dot product automatically.

function [d] = dotproduct(x, y)

end

%Print a row vector u dot column vector v in a manner consistent

%with the provided examples.

%Do not change this function.

function [] = printvectors(u, v)

%print u

n = size(u, 2);

fprintf("[");

for i = 1 : n-1

fprintf("%.4f ", u(i));

end

%print .

fprintf("%.4f].", u(n));

%print v

fprintf("[");

m = size(v, 1);

for i = 1 : m-1

fprintf("%.4f ", v(i));

end

fprintf("%.4f]", v(m));

end