rempet

3 views (last 30 days)
Niki
Niki on 7 Sep 2011
I have a matrix and a vector, I want to repmat them the same my mean is that if I change the first row of the matrix I want this also happen the same for the vector,
  2 Comments
Niki
Niki on 7 Sep 2011
X=rand(4) and Y=rand(4,1)
for example
X=[ 0.1734 0.0605 0.6569 0.0155
0.3909 0.3993 0.6280 0.9841
0.8314 0.5269 0.2920 0.1672
0.8034 0.4168 0.4317 0.1062]
and
Y =
0.3724
0.1981
0.4897
0.3395
Then I want randomly change the X rows simultaneously with Y
for example next one X become
X=[ 0.3909 0.3993 0.6280 0.9841
0.8314 0.5269 0.2920 0.1672
0.8034 0.4168 0.4317 0.1062
0.1734 0.0605 0.6569 0.0155
]
(the first row went to the last row )
for Y also the same
Y=[0.1981
0.4897
0.3395
0.3724
]

Sign in to comment.

Accepted Answer

Fangjun Jiang
Fangjun Jiang on 7 Sep 2011
X=rand(4)
Y=rand(4,1)
Index=[2 3 4 1];
X=X(Index,:)
Y=Y(Index,:)
  5 Comments
Fangjun Jiang
Fangjun Jiang on 7 Sep 2011
You are welcome! BTW, Index=randperm(4);X=X(Index,:); works too!

Sign in to comment.

More Answers (2)

Honglei Chen
Honglei Chen on 7 Sep 2011
An alternative approach is to use left-multiply to achieve row manipulation. In your case, if you want to move your first row to the last, the corresponding matrix is
T = [0 1 0 0;0 0 1 0;0 0 0 1;1 0 0 0]
Then you can do
X = T*X
Y = T*Y
As long as you can build T, then you can the manipulate them together.
HTH
  1 Comment
Niki
Niki on 7 Sep 2011
Thanks Honglei

Sign in to comment.


Walter Roberson
Walter Roberson on 7 Sep 2011
What you are asking to do is not possible with ordinary numeric datatypes.
You could create a new object-oriented data class that did the work for you.

Categories

Find more on Matrices and Arrays in Help Center and File Exchange

Tags

Community Treasure Hunt

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

Start Hunting!