Converting Linear Equations to Matrix Form

8 views (last 30 days)
I am trying to convert the following equations into matrix form.
  1 Comment
Mohammadali Mozafarian
Mohammadali Mozafarian on 25 Feb 2021
Hi Connor,
You wouldn't need to ask the question here. If you review your lecture notes, you will find the answer there!

Sign in to comment.

Answers (2)

Bjorn Gustavsson
Bjorn Gustavsson on 24 Feb 2021
Is k some sort of propagation (time? space?) index and you want to convert these equations into a matrix-format, or are these actually some scalilng-factors?
In case 1:
C = [C11 0 0 0;C21 C22 0 0;0 C32 C33 0;0 0 C43 C44];
ad = [a;d;0;0];
x_next = C*x_curr + ad;
In case 2:
C = [C11*k-(k+1) 0 0 0;C21*k C22*k-(k+1) 0 0;0 C32*k C33*k-(k+1) 0;0 0 C43*k C44*k-(k+1)];
ad = -[a;d;0;0];
x = C\ad;
Think I got this right, not checked or tested.
Bjorn Gustavsson
Bjorn Gustavsson on 24 Feb 2021
Before you continue coding you'd better get the context! You need to know if you're implementing a stepper that intends to solve some sort of difference equation (or ordinary differential equations), or if you're supposed to get a solution for a single system of equations. Before you code something you have to know what problem you're supposed to solve.
Regardless of that I've given you solutions to the two plausible variants I could guess, from there it's your job to get the information you need to understand which one to chose.

Sign in to comment.

Hernia Baby
Hernia Baby on 24 Feb 2021
Edited: Hernia Baby on 24 Feb 2021
You need to convert following form.
X(i+1) = C*X(i) + a(i)
Xo = [0 0 0 0]';
X(:,1) = Xo;
C11 = 1;
C21 = 2; C22 = 3;
C32 = 4; C33 = 5;
C43 = 6; C44 = 7;
C = [C11 0 0 0; C21 C22 0 0; 0 C32 C33 0; 0 0 C43 C44]
step_num = 5;
a = zeros(4,step_num);
a(1:2,:) = randn(2, step_num);
i = 1;
while i <= step_num
X = C*X + a(:,i);
i = i + 1;


Find more on Loops and Conditional Statements in Help Center and File Exchange




Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by