# Tuning parameters¶

The following tuning parameters have been exposed since they are system-dependent and can have a large impact on performance.

## LocalSymvBlocksize¶

template<>
void SetLocalSymvBlocksize<T>(int blocksize)

Sets the local blocksize for the distributed Symv() routine for datatype T. It is set to 64 by default and is important for the reduction of a real symmetric matrix to symmetric tridiagonal form.

template<>
int LocalSymvBlocksize<T>()

Retrieves the local Symv() blocksize for datatype T.

## LocalTrrkBlocksize¶

template<>
void SetLocalTrrkBlocksize<T>(int blocksize)

Sets the local blocksize for the distributed LocalTrrk routine for datatype T. It is set to 64 by default and is important for routines that perform distributed Syrk() or Herk() updates, e.g., Cholesky factorization.

template<>
int LocalTrrkBlocksize<T>()

Retrieves the local blocksize for the distributed LocalTrrk routine for datatype T.

## LocalTrr2kBlocksize¶

template<>
void SetLocalTrr2kBlocksize<T>(int blocksize)

Sets the local blocksize for the distributed LocalTrr2k routine for datatype T. It is set to 64 by default and is important for routines that perform distributed Syr2k() or Her2k() updates, e.g., Householder tridiagonalization.

template<>
int LocalTrr2kBlocksize<T>()

Retrieves the local blocksize for the distributed LocalTrr2k routine for datatype T.