rempet

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,

[Oleg Komarov]

Your request doesn't make sense without additional information. What's your goal? How the change happens?

[Niki]

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

]

Answer 1

[Fangjun Jiang]

X=rand(4)
Y=rand(4,1)
Index=[2 3 4 1];
X=X(Index,:)
Y=Y(Index,:)

[Niki]

Thanks, but I would like to perform it automatically and not doing it manually, I would like to perform it randomly and not based on my knowledge

[Fangjun Jiang]

What do you mean? I thought your question is about the synchronization of changes made on two matrix, which the code does. If you want to do it randomly, then come up with a random way to generate the Index. You have to specify the Index, do you? Maybe Index=randperm(4)?

[Niki]

Yes, It works

just we should use of

Index=randperm(4)';

[Niki]

Thanks Fangiun, you are always ready for my questions and at least you read my questions and try to answer , Thanks

I gave you a vote just for your kindness

[Fangjun Jiang]

You are welcome! BTW, Index=randperm(4);X=X(Index,:); works too!

Answer 2

[Honglei Chen]

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

[Niki]

Thanks Honglei

Answer 3

[Walter Roberson]

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.