genfit::tools Namespace Reference

Functions
void	invertMatrix (const TMatrixDSym &mat, TMatrixDSym &inv, double *determinant=NULL)
	Invert a matrix, throwing an Exception when inversion fails. Optional calculation of determinant. More...
void	invertMatrix (TMatrixDSym &mat, double *determinant=NULL)
	Same, replacing its argument. More...
bool	transposedForwardSubstitution (const TMatrixD &R, TVectorD &b)
	Solves R^t x = b, replacing b with the solution for x. R is assumed to be upper diagonal. More...
bool	transposedForwardSubstitution (const TMatrixD &R, TMatrixD &b, int nCol)
	Same, for a column of the matrix b. More...
bool	transposedInvert (const TMatrixD &R, TMatrixD &inv)
	Inverts the transpose of the upper right matrix R into inv. More...
void	QR (TMatrixD &A)
	Replaces A with an upper right matrix connected to A by an orthongonal transformation. I.e., it computes R from a QR decomposition of A = QR, replacing A. More...
void	QR (TMatrixD &A, TVectorD &b)
	Replaces A with an upper right matrix connected to A by an orthongonal transformation. I.e., it computes R from a QR decomposition of A = QR, replacing A. Also replaces b by Q'b where Q' is the transposed of Q. More...
void	safeAverage (const TMatrixDSym &C1, const TMatrixDSym &C2, TMatrixDSym &result)
	This averages the covariance matrices C1, C2 in a numerically stable way by using matrix square roots. This code is in no way optimized so use with care if speed is a concern. More...

Function Documentation

void genfit::tools::invertMatrix	(	const TMatrixDSym &	mat,
		TMatrixDSym &	inv,
		double *	determinant = NULL
	)

Invert a matrix, throwing an Exception when inversion fails. Optional calculation of determinant.

void genfit::tools::invertMatrix	(	TMatrixDSym &	mat,
		double *	determinant = NULL
	)

Same, replacing its argument.

void genfit::tools::QR

(

TMatrixD &

A

)

Replaces A with an upper right matrix connected to A by an orthongonal transformation. I.e., it computes R from a QR decomposition of A = QR, replacing A.

Referenced by PndLmdCalStrip::DigiStripFromPoint(), and PndSdsCalcStripDif::GetStrips().

void genfit::tools::QR	(	TMatrixD &	A,
		TVectorD &	b
	)

Replaces A with an upper right matrix connected to A by an orthongonal transformation. I.e., it computes R from a QR decomposition of A = QR, replacing A. Also replaces b by Q'b where Q' is the transposed of Q.

void genfit::tools::safeAverage	(	const TMatrixDSym &	C1,
		const TMatrixDSym &	C2,
		TMatrixDSym &	result
	)

This averages the covariance matrices C1, C2 in a numerically stable way by using matrix square roots. This code is in no way optimized so use with care if speed is a concern.

bool genfit::tools::transposedForwardSubstitution	(	const TMatrixD &	R,
		TVectorD &	b
	)

Solves R^t x = b, replacing b with the solution for x. R is assumed to be upper diagonal.

bool genfit::tools::transposedForwardSubstitution	(	const TMatrixD &	R,
		TMatrixD &	b,
		int	nCol
	)

Same, for a column of the matrix b.

bool genfit::tools::transposedInvert	(	const TMatrixD &	R,
		TMatrixD &	inv
	)

Inverts the transpose of the upper right matrix R into inv.