ojAlgo Linear Algebra Benchmark (ojLAB)

Benchmarks and internal tuning tools for ojAlgo linear algebra operations, using JMH (Java Microbenchmark Harness).

What's in here

This project serves two purposes:

Library comparison benchmarks

Comparing ojAlgo linear algebra operations against alternative Java libraries:

Library	Why it's included
EJML	Pure Java, no dependencies, high performance. Top quality pure Java alternative.
MTJ	Wraps BLAS/LAPACK via netlib-java, automatically switching between Java and native code. On macOS it defaults to Apple's vecLib. Included as a native code performance reference.
Apache Commons Math	The only linear algebra library backed by a large organisation (Apache). A baseline that alternatives must justify improving upon.

Benchmark classes in org.ojalgo.benchmark.lab cover: matrix multiplication, addition, scaling, transpose, decompositions (EVD, SVD, Cholesky), solvers (general, Hermitian, least squares), inversion, determinant, and pseudoinverse.

Internal tuning benchmarks

Benchmarks used to tune ojAlgo's internal implementation parameters:

• Threshold tuners (org.ojalgo.matrix.operation) -- determine at what matrix size operations should switch between serial and parallel execution, and between different multiplication strategies.
• Parallelism tuners (org.ojalgo.matrix.operation) -- find the optimal degree of parallelism for various matrix operations and Householder transformations.
• Decomposition tuners (org.ojalgo.matrix.decomposition) -- compare implementation variants (primitive vs raw arrays) for Cholesky, LU, QR, Eigenvalue, SVD, and Tridiagonal decompositions, and benchmark sparse LU operations.
• Array operation tuners (org.ojalgo.array.operation) -- tune DOT product unrolling, AXPY ordering, and norm calculations.
• Other -- DFT benchmarks, number parsing benchmarks, special function benchmarks, sparse array performance, and solver strategy selection.

Building and running

mvn clean install

Run a specific benchmark:

java -jar target/ojlab.jar org.ojalgo.benchmark.lab.FillByMultiplying

Replace FillByMultiplying with whichever benchmark you want to run. Use -l to list all available benchmarks:

java -jar target/ojlab.jar -l

Results

Benchmark results are published at: https://www.ojalgo.org/category/benchmarks/