Expokit is a numerical library that calculates the matrix exponential or it's operation on a vector.

This project is a manual translation of some expokit subroutines to C++. With a trivial modification, one can change them to C as well.

This project uses some utilities in the SLISC library, mainly for custom type definition and a COO Sparse matrix class that supports matrix-vector multiplication.

• The original code it translated as directly as possible except the following changes.
• Since C++ arrays are 0-based, some variables always have value that is -1 than it's fortran counterpart. Note that this include some function arguments. See the comments before each function for a complete list.
• since goto statement is deprecated, it's replaced with other structures.
• BLAS and LAPACK subroutines are replaced with corresponding CBLAS and LAPACKE from Intel's MKL library (currently free). With minor modifications, other CBLAS and LAPACKE may be used.

• Hermitian matrices up to 40-by-40 are tested with ZGEXPV and ZHEXPV, with results 2-3 digits less than machine precision.