Making a NxN matrix.

http://www.math.ufl.edu/~liqing/Courses/MAS3114/project_3.pdf

I have a homework assignment and i'm trying to figure out some functions that could help me write the matrix in this form (on that link i posted) like if i wanted to make a row with 1000 ones and not have to write 1 a thousand times.. In my class they don't teach us the software so yeah, any help will be appreciated, thank you.

Answer 1

[Paulo Silva]

We don't make homeworks, we only help with answers to specific questions and if we are kind enough we might give some tips:

doc ones   %execute this to see the documentation of the function ones
doc zeros  %execute this to see the documentation of the function zeros

Simple example:

m=zeros(10,10); %create one array with 10 rows and columns full of zeros
m(5,:)=1;       %all columns (:) from row number 5 are now equal to 1
m %see the array

Answer 2

[Image Analyst]

Like I said in my response to your post of this in the newsgroup:

Alan: To set an entire row to a value:

M(rowNumberToSet, :) = theValue;

Example:

M(42, :) = 2.718281828;

To set an entire column so a value:

M(:, columnNumberToSet) = theValue;

Example:

M(:, 69) = 3.14159;

This is basic MATLAB stuff - the stuff you learn the first couple of hours into it. You should find it early on in the "Getting Started" section of the help.

[Alan`]

if i want a pattern like this one:

{1 1 1 1}

{1 2 2 2}

{1 2 3 3}

{1 2 3 4}

where pretty much what this is is a nxn where n is 4. what i noticed was

A(1,:)=1

A(:,1)=1

A(2,2:)=2

A(3,3:)=3

A(4,4:)=4

does this mean: A(n, n:)=n ???

im trying to develop a while loop to get this pattern.. i know C programming i'm currently in that class as well but as i said before we dont get Matlab trayning in Linear Algebra so im not familiar with all the commands.. how do i make a for loop or while loop on a case like this one.. i know how to do it for other operations, just not in a matrix form. I'd appreciate some intuition in this.

[Alan`]

training***

[Andrei Bobrov]

Creates your matrix with loop.

% 1.

n = 4;

for j = n:-1:1, A(j,j:n)=j; A(j:n,j)=j; end

% 2

A=ones(n);

for j = 1:n, A(j:n,j:n)=j; end

[Andrei Bobrov]

Hi Alan! Creates your matrix without loops.

% 1

A = repmat(1:4,4,1);

A = min(A,A.');

% 2

A = repmat(1:4,4,1);

A = tril(A) + triu(A.',1)

[Walter Roberson]

Yaser Rostami comments to Andrei Bobrov

clear all; close all; clc m=zeros(5,7); g=0; c=numel(m); for d=1:c; g=1+g; m(d)=g; end