diff options
Diffstat (limited to 'scaddins')
-rw-r--r-- | scaddins/source/analysis/financial.cxx | 124 |
1 files changed, 86 insertions, 38 deletions
diff --git a/scaddins/source/analysis/financial.cxx b/scaddins/source/analysis/financial.cxx index 5ebfa4e28a44..9fe4609a3b5f 100644 --- a/scaddins/source/analysis/financial.cxx +++ b/scaddins/source/analysis/financial.cxx @@ -2,9 +2,9 @@ * * $RCSfile: financial.cxx,v $ * - * $Revision: 1.14 $ + * $Revision: 1.15 $ * - * last change: $Author: hr $ $Date: 2003-03-26 17:46:45 $ + * last change: $Author: hr $ $Date: 2003-04-28 15:14:48 $ * * The Contents of this file are made available subject to the terms of * either of the following licenses @@ -488,18 +488,72 @@ double SAL_CALL AnalysisAddIn::getOddlyield( constREFXPS& xOpt, } -double lcl_Sca_Analysis_CalcXirrDiff( const ScaDoubleList& rValues, const ScaDoubleList& rDates, double fGuessInt ) +// ============================================================================ +// XIRR helper functions + +#define V_(i) (*rValues.Get(i)) +#define D_(i) (*rDates.Get(i)) + +/** Calculates the resulting amount for the passed interest rate and the given XIRR parameters. */ +double lcl_sca_XirrResult( const ScaDoubleList& rValues, const ScaDoubleList& rDates, double fRate ) { - double fFirstDate = *rDates.Get( 0 ); - double fIntRate = fGuessInt + 1.0; - double fXirrDiff = 0.0; - for( sal_uInt32 nIndex = 0, nCount = rValues.Count(); nIndex < nCount; ++nIndex ) - fXirrDiff += *rValues.Get( nIndex ) / pow( fIntRate, (*rDates.Get( nIndex ) - fFirstDate) / 365.0 ); - return fXirrDiff; + /* V_0 ... V_n = input values. + D_0 ... D_n = input dates. + R = input interest rate. + + r := R+1 + E_i := (D_i-D_0) / 365 + + n V_i n V_i + f(R) = SUM ------- = V_0 + SUM ------- . + i=0 r^E_i i=1 r^E_i + */ + double D_0 = D_(0); + double r = fRate + 1.0; + double fResult = V_(0); + for( sal_uInt32 i = 1, nCount = rValues.Count(); i < nCount; ++i ) + fResult += V_(i) / pow( r, (D_(i) - D_0) / 365.0 ); + return fResult; +} + +/** Calculates the first derivation of lcl_sca_XirrResult(). */ +double lcl_sca_XirrResult_Deriv1( const ScaDoubleList& rValues, const ScaDoubleList& rDates, double fRate ) +{ + /* V_0 ... V_n = input values. + D_0 ... D_n = input dates. + R = input interest rate. + + r := R+1 + E_i := (D_i-D_0) / 365 + + n V_i + f'(R) = [ V_0 + SUM ------- ]' + i=1 r^E_i + + n V_i n E_i V_i + = 0 + SUM -E_i ----------- r' = - SUM ----------- . + i=1 r^(E_i+1) i=1 r^(E_i+1) + */ + double D_0 = D_(0); + double r = fRate + 1.0; + double fResult = 0.0; + for( sal_uInt32 i = 1, nCount = rValues.Count(); i < nCount; ++i ) + { + double E_i = (D_(i) - D_0) / 365.0; + fResult -= E_i * V_(i) / pow( r, E_i + 1.0 ); + } + return fResult; } +#undef V_ +#undef D_ + + +// ---------------------------------------------------------------------------- +// XIRR calculation + double SAL_CALL AnalysisAddIn::getXirr( - constREFXPS& xOpt, const SEQSEQ( double )& rValues, const SEQSEQ( sal_Int32 )& rDates, const ANY& rGuess ) THROWDEF_RTE_IAE + constREFXPS& xOpt, const SEQSEQ( double )& rValues, const SEQSEQ( sal_Int32 )& rDates, const ANY& rGuessRate ) THROWDEF_RTE_IAE { ScaDoubleList aValues, aDates; aValues.Append( rValues ); @@ -509,43 +563,37 @@ double SAL_CALL AnalysisAddIn::getXirr( THROW_IAE; // result interest rate, initialized with passed guessed rate, or 10% - double fResultInt = aAnyConv.getDouble( xOpt, rGuess, 0.1 ); - // lower boundary for iteration -> lowest possible is -100% - double fLowerInt = -1; - // upper boundary is open end -> try to find appropriate limit, start with 100% - double fUpperInt = 1; - while( (fUpperInt < 1e20) && (lcl_Sca_Analysis_CalcXirrDiff( aValues, aDates, fUpperInt ) > 0.0) ) - fUpperInt *= 1e2; - - // maximum epsilon (upper-lower difference) for end of iteration - static const double fMaxEpsilon = 1e-10; - // maximum XIRR result for end of iteration (ideal result is 0.0) - static const double fMaxXirrDiff = 1e-13; - // true = a result has been found - bool bResultReached = false; - - // iteration counter - sal_Int32 nIteration = 0; + double fResultRate = aAnyConv.getDouble( xOpt, rGuessRate, 0.1 ); + if( fResultRate <= -1 ) + THROW_IAE; + + // maximum epsilon for end of iteration + static const double fMaxEps = 1e-10; // maximum number of iterations - static const sal_Int32 nMaxIterations = 200; + static const sal_Int32 nMaxIter = 50; - while( !bResultReached && (++nIteration <= nMaxIterations) ) + // Newton's method - try to find a fResultRate, so that lcl_sca_XirrResult() returns 0. + double fNewRate, fRateEps, fResultValue; + sal_Int32 nIter = 0; + bool bContLoop; + do { - double fXirrDiff = lcl_Sca_Analysis_CalcXirrDiff( aValues, aDates, fResultInt ); - if( fXirrDiff < 0.0 ) - fUpperInt = fResultInt; - else if( fXirrDiff > 0.0 ) - fLowerInt = fResultInt; - fResultInt = (fUpperInt + fLowerInt) / 2.0; - bResultReached = (fabs( fUpperInt - fLowerInt ) <= fMaxEpsilon) || (fabs( fXirrDiff ) <= fMaxXirrDiff); + fResultValue = lcl_sca_XirrResult( aValues, aDates, fResultRate ); + fNewRate = fResultRate - fResultValue / lcl_sca_XirrResult_Deriv1( aValues, aDates, fResultRate ); + fRateEps = fabs( fNewRate - fResultRate ); + fResultRate = fNewRate; + bContLoop = (fRateEps > fMaxEps) && (fabs( fResultValue ) > fMaxEps); } + while( bContLoop && (++nIter < nMaxIter) ); - if( !bResultReached ) + if( bContLoop ) THROW_IAE; - RETURN_FINITE( fResultInt ); + RETURN_FINITE( fResultRate ); } +// ============================================================================ + double SAL_CALL AnalysisAddIn::getXnpv( double fRate, const SEQSEQ( double )& rValues, const SEQSEQ( sal_Int32 )& rDates ) THROWDEF_RTE_IAE { |