ltiPerformanceConfig.h File Reference

Definition of constants that are used to tweak the performance of some algorithm but need not be changed for every call of a method. More...

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Defines
#define	_LTI_PERFORMANCE_MATRIX_MATRIX_MULTIPLY 65
#define	_LTI_PERFORMANCE_QR_DECOMPOSITION 50
#define	_LTI_PERFORMANCE_SORT_STOP_QUICKSORT 10

Detailed Description

Definition of constants that are used to tweak the performance of some algorithm but need not be changed for every call of a method.

Usually, these constants are architecture dependent, mostly cache. The default values in this file were determined on a P4 1600 with 512 RAM.

#define _LTI_PERFORMANCE_MATRIX_MATRIX_MULTIPLY 65

Multiplication of two matrices in lti::matrix is faster if the second matrix is transposed first when that matrix is large.

Large is defined below.

#define _LTI_PERFORMANCE_QR_DECOMPOSITION 50

The QR decomposition algorithm (lti::qrDecomposition) accesses the data matrix column wise.

Depending on the size it is faster to transpose first and transpose the results again.

#define _LTI_PERFORMANCE_SORT_STOP_QUICKSORT 10

lti::sort uses quicksort down to a certain number of elements to sort after which it uses a simple sorting algorithm.

The value below sets that threshold.