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kmymoney/kmymoney2/mymoney/mymoneyfinancialcalculator.h

318 lines
9.6 KiB

/***************************************************************************
mymoneyfinancialcalculator.h - description
-------------------
begin : Tue Oct 21 2003
copyright : (C) 2000-2003 by Michael Edwardes
email : mte@users.sourceforge.net
Javier Campos Morales <javi_c@users.sourceforge.net>
Felix Rodriguez <frodriguez@users.sourceforge.net>
John C <thetacoturtle@users.sourceforge.net>
Thomas Baumgart <ipwizard@users.sourceforge.net>
Kevin Tambascio <ktambascio@users.sourceforge.net>
***************************************************************************/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
#ifndef MYMONEYFINANCIALCALCULATOR_H
#define MYMONEYFINANCIALCALCULATOR_H
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <cmath>
// ----------------------------------------------------------------------------
// QT Includes
// ----------------------------------------------------------------------------
// KDE Includes
// ----------------------------------------------------------------------------
// Project Includes
#include <kmymoney/export.h>
#ifdef _GLIBCPP_HAVE_MODFL
#define HAVE_LONG_DOUBLE 1
#endif
#ifndef HAVE_LONG_DOUBLE
#define HAVE_LONG_DOUBLE 0
#endif
#if HAVE_LONG_DOUBLE
#define FCALC_DOUBLE long double
#else
#define FCALC_DOUBLE double
#define modfl(a,b) modf(a,b)
#define roundl(a) round(a)
#define powl(a,b) pow(a,b)
#define expl(a) exp(a)
#define logl(a) log(a)
#define floorl(a) floor(a)
#define fabsl(a) fabs(a)
#endif
/**
* @author Thomas Baumgart
*/
/**
* This class implements the financial calculator as found in GNUCash.
* For a detailed description of the algorithms see
* gnucash-1.8.5/src/doc/finutil.html.
*/
class KMYMONEY_EXPORT MyMoneyFinancialCalculator
{
public:
MyMoneyFinancialCalculator();
~MyMoneyFinancialCalculator();
/**
* This method calculates the number of payments required to amortize
* the loan. ir, pv, fv and pmt must be set. It sets the member variable
* m_npp with the calculated value.
*
* @return number of periodic payments
*
* @exception If one of the required values is not set, a MyMoneyException
* will be thrown
*/
FCALC_DOUBLE numPayments();
/**
* This method calculates the amount of the payment (amortization and interest)
* for the loan. ir, pv, fv and npp must be set. It sets the member variable
* m_pmt with the calculated value.
*
* @return amount of payment
*
* @exception If one of the required values is not set, a MyMoneyException
* will be thrown
*/
FCALC_DOUBLE payment();
/**
* This method calculates the present value
* for the loan. ir, pmt, fv and npp must be set. It sets the member variable
* m_pv with the calculated value.
*
* @return present value of loan
*
* @exception If one of the required values is not set, a MyMoneyException
* will be thrown
*/
FCALC_DOUBLE presentValue();
/**
* This method calculates the future value
* for the loan. ir, pmt, pv and npp must be set. It sets the member variable
* m_fv with the calculated value.
*
* @return future value of loan
*
* @exception If one of the required values is not set, a MyMoneyException
* will be thrown
*/
FCALC_DOUBLE futureValue();
/**
* This method calculates the nominal interest rate
* for the loan. fv, pmt, pv and npp must be set. It sets the member variable
* m_ir with the calculated value.
*
* @return interest rate of the loan
*
* @exception If one of the required values is not set, a MyMoneyException
* will be thrown
*/
FCALC_DOUBLE interestRate();
/**
* This method calculates the interest due for the next payment according
* to the equation
*
* id[n] = (pv[n-1] + (X * pmt)) * i
*
* with
*
* - pv[n-1]\n
* the present value at the end of the last period
* - X\n
* 0 for end of period payments, 1 for beginning of period payments
* - pmt\n
* the periodic payment amount and
* - i\n
* the effective interest rate
*
* pv[n-1] will be the value as set with setPv(), i will be calculated
* from the nominal interest rate as set with setIr(), pmt will be the
* value as set with setPmt() and X is determined by the argument to
* setBep().
*
* @return the interest amount
*/
FCALC_DOUBLE interestDue(void) const;
/**
* This method sets the rounding precision to @p prec fractional
* digits. The default of @p is 2. Rounding is applied to pv, pmt
* and fv.
*
* @param prec Number of fractional digits after rounding.
*/
void setPrec(const unsigned short prec = 2);
/**
* This method sets the number of payment periods to the value
* passed in parameter @p npp. The length of a period is controlled
* via setPF().
*
* @param npp number of payment periods
*/
void setNpp(const FCALC_DOUBLE npp);
FCALC_DOUBLE npp(void) const { return m_npp; };
/**
* This method sets the payment frequency. The parameter @p PF
* specifies the payments per year.
*
* - 1 == annual
* - 2 == semi-annual
* - 3 == tri-annual
* - 4 == quaterly
* - 6 == bi-monthly
* - 12 == monthly
* - 24 == semi-monthly
* - 26 == bi-weekly
* - 52 == weekly
* - 360 == daily
* - 365 == daily
*
* @param PF length of payment period (default is 12 - monthly)
*/
void setPF(const unsigned short PF = 12);
/**
* This method sets the compounding frequency. The parameter @p CF
* specifies the compounding period per year.
*
* - 1 == annual
* - 2 == semi-annual
* - 3 == tri-annual
* - 4 == quaterly
* - 6 == bi-monthly
* - 12 == monthly
* - 24 == semi-monthly
* - 26 == bi-weekly
* - 52 == weekly
* - 360 == daily
* - 365 == daily
*
* @param CF length of compounding period (default is 12 - monthly)
*/
void setCF(const unsigned short CF = 12);
/**
* This method controls whether the interest will be calculated
* at the end of the payment period of at it's beginning.
*
* @param bep if @p false (default) then the interest is due at the
* end of the payment period, if @p true at it's beginning.
*/
void setBep(const bool bep = false);
/**
* This method controls whether the interest is compounded in periods
* or continously.
*
* @param disc if @p true (default) then the interest is compounded in
* periods, if @p false continously.
*/
void setDisc(const bool disc = true);
/**
* This method sets the nominal interest rate to the value passed
* in the argument @p ir.
*
* @param ir nominal interest rate
*/
void setIr(const FCALC_DOUBLE ir);
FCALC_DOUBLE ir(void) const { return m_ir; };
/**
* This method sets the present value to the value passed
* in the argument @p pv.
*
* @param pv present value
*/
void setPv(const FCALC_DOUBLE pv);
FCALC_DOUBLE pv(void) const { return m_pv; };
/**
* This method sets the payment amount to the value passed
* in the argument @p pmt.
*
* @param pmt payment amount
*/
void setPmt(const FCALC_DOUBLE pmt);
FCALC_DOUBLE pmt(void) const { return m_pmt; };
/**
* This method sets the future value to the value passed
* in the argument @p fv.
*
* @param fv future value
*/
void setFv(const FCALC_DOUBLE fv);
FCALC_DOUBLE fv(void) const { return m_fv; };
private:
FCALC_DOUBLE eff_int(void) const;
FCALC_DOUBLE nom_int(const FCALC_DOUBLE eint) const;
FCALC_DOUBLE rnd(const FCALC_DOUBLE x) const;
FCALC_DOUBLE _Ax(const FCALC_DOUBLE eint) const;
FCALC_DOUBLE _Bx(const FCALC_DOUBLE eint) const;
FCALC_DOUBLE _Cx(const FCALC_DOUBLE eint) const;
FCALC_DOUBLE _fi(const FCALC_DOUBLE eint) const;
FCALC_DOUBLE _fip(const FCALC_DOUBLE eint) const;
private:
FCALC_DOUBLE m_ir; // nominal interest rate
FCALC_DOUBLE m_pv; // present value
FCALC_DOUBLE m_pmt; // periodic payment
FCALC_DOUBLE m_fv; // future value
FCALC_DOUBLE m_npp; // number of payment periods
unsigned short m_CF; // compounding frequency
unsigned short m_PF; // payment frequency
unsigned short m_prec; // precision for roundoff for pv, pmt and fv
// i is not rounded, n is integer
bool m_bep; // beginning/end of period payment flag
bool m_disc; // discrete/continous compounding flag
unsigned short m_mask; // available value mask
#define PV_SET 0x0001
#define IR_SET 0x0002
#define PMT_SET 0x0004
#define NPP_SET 0x0008
#define FV_SET 0x0010
};
#endif