#ifndef COVMATRIXSIMILARITY_H
#define COVMATRIXSIMILARITY_H

// $Id: Similarity.h,v 1.2 2003/07/03 15:11:25 sachs Exp $
// David Sachs - Fermilab - July 2003
//
// Define Similarity transformation functions for CovMatrices

// The normal intent of these functions is for P to be an orthogonal
// matrix, but the transformations are valid for any matrix P
// The matrix P is supplied as a vector if vector<double>

#include "CovMatrices/CovMatrix.h"

namespace CovMatrices
{
  // Provide transform result = P * A * Pt
  void similarityPAPt( 
	const CovMatrix& a, 	// original CovMatrix
	const std::vector< std::vector<double> > p,
	CovMatrix& result);	// result CovMatrix

  // Provide transform: result = Pt * A * P
  void similarityPtAP( 
	const CovMatrix& a, 	// original CovMatrix
	const std::vector< std::vector<double> > p,
	CovMatrix& result);	// result CovMatrix
}

#endif