Subject: [ublas] [uBLAS] What's inside the uBLAS matrix multiplication algorithm?
From: Anders Kabell Kristensen (dalko_at_[hidden])
Date: 2010-06-10 08:14:06
Hi there, this is my first post. Thank you for your time.
I'm implementing an algorithm where fast matrix multiplication is
essential and the theoretical running-time is closely connected to the
running-time of the matrix multiplication algorithm being used. As a
matter of fact, some choices within the algorithm are made on the basis
of the time complexity of matrix multiplication. Therefore, I'm
interested in knowing exactly what's inside the uBLAS matrix
multiplication algorithm. For example, naive mat.mult. has a complexity
of O(n^3), whereas Strassen's method
(http://en.wikipedia.org/wiki/Strassen_algorithm) has a complexity of
O(n^2.807).
I suppose the uBLAS algorithm is very complex and varies between methods
such as Strassen's and even the naive approach when appropriate, right?
Can anyone give an outline?
Would it be possible to make a realistic estimate on the complexity? I
guess that would be an estimate about the performance on square matrices.
And a related question: is it possible to force uBLAS to use naive
mattrix multiplication? I need to use the naive approach, but if I
implement it myself, I guess I wont be competitive with uBLAS.
Thanks again,
Anders K