how to append row or column to a matrix?

[Yingjun Wu]

Dear all,

I am a newbie to jblas and I am seeking a way to append row or column to a matrix at runtime. It seems that the number of rows and columns are set at initialization time, using the constructor like:

DoubleMatrix matrix=new DoubleMatrix(10, 10);

However, what if I want to add a row or column to the matrix to get a 11*10 or 10*11 matrix? Thanks.

Regards,

Yingjun

[Mikio Braun]

concatHorizontally and concatVertically are the methods you are looking for.

-M

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[Christos Boutsidis]

Hi, i have noticed that this is extremely slow. For example, let's say you have a bilion by 10 matrix A and just
want to append a row. then, this shouldn't take that long. but concatVertically creates an m x 10 matrix B and
then sets the top part of B to A. here m = 1 billion + 1, that's why creating the whole B is very expensive.
Do you know of any alternative solution ?