How to concatenate matrices

9 Ansichten (letzte 30 Tage)
jake stan
jake stan am 2 Mär. 2018
Bearbeitet: Pawel Jastrzebski am 2 Mär. 2018
Create a 4x4 magic matrix A. Use MATLAB to assemble a new matrix B. I'm not sure how to turn the 4x4 matrix A in to a 2x2 matrix B, where first row: A 2A, second row: A^2 A+2
A = magic(4)
B = [A 2A; A.^2 A+2]

Akzeptierte Antwort

Pawel Jastrzebski
Pawel Jastrzebski am 2 Mär. 2018
You must have got an error message when executing - what did it say? That should be your first clue as to what's wrong with the code.
In your case, the multiplication sign is missing '*'.
A = magic(4)
B = [A 2*A; A.^2 A+2]
Output:
>> B
B =
16 2 3 13 32 4 6 26
5 11 10 8 10 22 20 16
9 7 6 12 18 14 12 24
4 14 15 1 8 28 30 2
256 4 9 169 18 4 5 15
25 121 100 64 7 13 12 10
81 49 36 144 11 9 8 14
16 196 225 1 6 16 17 3
  3 Kommentare
Pawel Jastrzebski
Pawel Jastrzebski am 2 Mär. 2018
Bearbeitet: Pawel Jastrzebski am 2 Mär. 2018
"." means it's an 'element-wise' operation. You need to have two matrices of the same size and the respective elements in them will be multiplied/divied/raised to the power.
If you ommit the "." it's considered as a normal matrix operation.
Jan
Jan am 2 Mär. 2018
@jake stan: A.^2 squares the elements of the array A, while A^2 calculates A*A with the matrix multiplication.

Melden Sie sich an, um zu kommentieren.

Weitere Antworten (0)

Kategorien

Mehr zu Creating and Concatenating Matrices finden Sie in Help Center und File Exchange

Tags

Community Treasure Hunt

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

Start Hunting!

Translated by