Matrix multiplication in java

Question

I wanted to do matrix multiplication in Java, and the speed needs to be very good.

I was thinking of calling R through java to achieve this.

I had a couple of Qs though:

1. Is calling R using Java a good idea? If yes, are there any code samples that can be shared?

2. What are the other ways that can be considered to do matrix multiplication in Java?

Update:

My colleague who quit the firm was a C# programmer, who was forced to write Java code that involved matrix multiplication.

-- He has written his own DataTable class in Java, in order to be able to

a) create indexes to sort and join with other DataTables

b) matrix multiplication.

So, I want to essentially clean up the code, and thought using something like R within Java will help me focus on business logic rather than sorting, joining, matrix multiplication, etc.

Answer 1

您可以使用矩阵包，例如JAMA 。

Answer 2

There are several stackoverflow questions on using R with Java. This is simple with JRI . See this question for an example: R from within Java . Once you have integrated your code, doing the matrix multiplication in R is trivial. If you have two matrices, a and b , you would simply call: a %*% b .

If you want to stay in pure Java and work with a mathematics library, you can also look into using Colt (which is adapted from JAMA ), although you could be better off just using JAMA directly .

Another option would be to use Incanter from Clojure (which provides a wrapper around Parallel Colt , amongst other things), and then call it as a Jar from Java. It's trivial to integrate Clojure into Java, and if all you want is matrix multiplication, that will be easier for you than using R.

Answer 3

Another vote for jblas . all the methods are like you'd expect them to be.

Answer 4

EJML seems to be a promising new one for fast multiplication. They have benchmarks on their site to show what they claim to be fast times for matrix multiplication.

Answer 5

Parallel colt is an effective library to perform matrix operations .

Other good matrix libraries would include jblas and ujmp

All of these packages are effective. jblas is my personal favourite . It has good documentation and straight forward unlike ujmp