diff options
Diffstat (limited to 'src/financial.c')
| -rw-r--r-- | src/financial.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/src/financial.c b/src/financial.c new file mode 100644 index 0000000..94a21c0 --- /dev/null +++ b/src/financial.c @@ -0,0 +1,294 @@ +/* Copyright (c) 1987-2008 Sun Microsystems, Inc. All Rights Reserved. + * Copyright (c) 2008-2009 Robert Ancell + * + * 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, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA + * 02111-1307, USA. + */ + +#include <glib/gi18n.h> + +#include "financial.h" +#include "mp.h" + +static void +calc_ctrm(MathEquation *equation, MPNumber *t, MPNumber *pint, MPNumber *fv, MPNumber *pv) +{ + +/* Cterm - pint (periodic interest rate). + * fv (future value). + * pv (present value). + * + * RESULT = log(fv / pv) / log(1 + pint) + */ + MPNumber MP1, MP2, MP3, MP4; + + mp_divide(fv, pv, &MP1); + mp_ln(&MP1, &MP2); + mp_add_integer(pint, 1, &MP3); + mp_ln(&MP3, &MP4); + mp_divide(&MP2, &MP4, t); +} + + +static void +calc_ddb(MathEquation *equation, MPNumber *t, MPNumber *cost, MPNumber *life, MPNumber *period) +{ + +/* Ddb - cost (amount paid for asset). + * life (useful life of the asset). + * period (time period for depreciation allowance). + * + * bv = 0.0; + * for (i = 0; i < life; i++) + * { + * VAL = ((cost - bv) * 2) / life + * bv += VAL + * } + * RESULT = VAL + * + */ + + int i; + int len; + MPNumber MPbv, MP1, MP2; + + mp_set_from_integer(0, &MPbv); + len = mp_cast_to_int(period); + for (i = 0; i < len; i++) { + mp_subtract(cost, &MPbv, &MP1); + mp_multiply_integer(&MP1, 2, &MP2); + mp_divide(&MP2, life, t); + mp_set_from_mp(&MPbv, &MP1); + mp_add(&MP1, t, &MPbv); /* TODO: why result is MPbv, for next loop? */ + } + + if (len >= 0) { + math_equation_set_status (equation, ("Error: the number of periods must be positive")); + mp_set_from_integer(0, t); + } +} + + +static void +calc_fv(MathEquation *equation, MPNumber *t, MPNumber *pmt, MPNumber *pint, MPNumber *n) +{ + +/* Fv - pmt (periodic payment). + * pint (periodic interest rate). + * n (number of periods). + * + * RESULT = pmt * (pow(1 + pint, n) - 1) / pint + */ + + MPNumber MP1, MP2, MP3, MP4; + + mp_add_integer(pint, 1, &MP1); + mp_xpowy(&MP1, n, &MP2); + mp_add_integer(&MP2, -1, &MP3); + mp_multiply(pmt, &MP3, &MP4); + mp_divide(&MP4, pint, t); +} + + +static void +calc_gpm(MathEquation *equation, MPNumber *t, MPNumber *cost, MPNumber *margin) +{ + +/* Gpm - cost (cost of sale). + * margin (gross profit margin. + * + * RESULT = cost / (1 - margin) + */ + + MPNumber MP1, MP2; + + mp_set_from_integer(1, &MP1); + mp_subtract(&MP1, margin, &MP2); + mp_divide(cost, &MP2, t); +} + + +static void +calc_pmt(MathEquation *equation, MPNumber *t, MPNumber *prin, MPNumber *pint, MPNumber *n) +{ + +/* Pmt - prin (principal). + * pint (periodic interest rate). + * n (term). + * + * RESULT = prin * (pint / (1 - pow(pint + 1, -1 * n))) + */ + + MPNumber MP1, MP2, MP3, MP4; + + mp_add_integer(pint, 1, &MP1); + mp_multiply_integer(n, -1, &MP2); + mp_xpowy(&MP1, &MP2, &MP3); + mp_multiply_integer(&MP3, -1, &MP4); + mp_add_integer(&MP4, 1, &MP1); + mp_divide(pint, &MP1, &MP2); + mp_multiply(prin, &MP2, t); +} + + +static void +calc_pv(MathEquation *equation, MPNumber *t, MPNumber *pmt, MPNumber *pint, MPNumber *n) +{ + +/* Pv - pmt (periodic payment). + * pint (periodic interest rate). + * n (term). + * + * RESULT = pmt * (1 - pow(1 + pint, -1 * n)) / pint + */ + + MPNumber MP1, MP2, MP3, MP4; + + mp_add_integer(pint, 1, &MP1); + mp_multiply_integer(n, -1, &MP2); + mp_xpowy(&MP1, &MP2, &MP3); + mp_multiply_integer(&MP3, -1, &MP4); + mp_add_integer(&MP4, 1, &MP1); + mp_divide(&MP1, pint, &MP2); + mp_multiply(pmt, &MP2, t); +} + + +static void +calc_rate(MathEquation *equation, MPNumber *t, MPNumber *fv, MPNumber *pv, MPNumber *n) +{ + +/* Rate - fv (future value). + * pv (present value). + * n (term). + * + * RESULT = pow(fv / pv, 1 / n) - 1 + */ + + MPNumber MP1, MP2, MP3, MP4; + + mp_divide(fv, pv, &MP1); + mp_set_from_integer(1, &MP2); + mp_divide(&MP2, n, &MP3); + mp_xpowy(&MP1, &MP3, &MP4); + mp_add_integer(&MP4, -1, t); +} + + +static void +calc_sln(MathEquation *equation, MPNumber *t, MPNumber *cost, MPNumber *salvage, MPNumber *life) +{ + +/* Sln - cost (cost of the asset). + * salvage (salvage value of the asset). + * life (useful life of the asset). + * + * RESULT = (cost - salvage) / life + */ + + MPNumber MP1; + mp_subtract(cost, salvage, &MP1); + mp_divide(&MP1, life, t); +} + + +static void +calc_syd(MathEquation *equation, MPNumber *t, MPNumber *cost, MPNumber *salvage, MPNumber *life, MPNumber *period) +{ + +/* Syd - cost (cost of the asset). + * salvage (salvage value of the asset). + * life (useful life of the asset). + * period (period for which depreciation is computed). + * + * RESULT = (cost - salvage) * (life - period + 1) / + * (life * (life + 1)) / 2 + */ + + MPNumber MP1, MP2, MP3, MP4; + + mp_subtract(life, period, &MP2); + mp_add_integer(&MP2, 1, &MP3); + mp_add_integer(life, 1, &MP2); + mp_multiply(life, &MP2, &MP4); + mp_set_from_integer(2, &MP2); + mp_divide(&MP4, &MP2, &MP1); + mp_divide(&MP3, &MP1, &MP2); + mp_subtract(cost, salvage, &MP1); + mp_multiply(&MP1, &MP2, t); +} + + +static void +calc_term(MathEquation *equation, MPNumber *t, MPNumber *pmt, MPNumber *fv, MPNumber *pint) +{ + +/* Term - pmt (periodic payment). + * fv (future value). + * pint (periodic interest rate). + * + * RESULT = log(1 + (fv * pint / pmt)) / log(1 + pint) + */ + + MPNumber MP1, MP2, MP3, MP4; + + mp_add_integer(pint, 1, &MP1); + mp_ln(&MP1, &MP2); + mp_multiply(fv, pint, &MP1); + mp_divide(&MP1, pmt, &MP3); + mp_add_integer(&MP3, 1, &MP4); + mp_ln(&MP4, &MP1); + mp_divide(&MP1, &MP2, t); +} + + +void +do_finc_expression(MathEquation *equation, int function, MPNumber *arg1, MPNumber *arg2, MPNumber *arg3, MPNumber *arg4) +{ + MPNumber result; + switch (function) { + case FINC_CTRM_DIALOG: + calc_ctrm(equation, &result, arg1, arg2, arg3); + break; + case FINC_DDB_DIALOG: + calc_ddb(equation, &result, arg1, arg2, arg3); + break; + case FINC_FV_DIALOG: + calc_fv(equation, &result, arg1, arg2, arg3); + break; + case FINC_GPM_DIALOG: + calc_gpm(equation, &result, arg1, arg2); + break; + case FINC_PMT_DIALOG: + calc_pmt(equation, &result, arg1, arg2, arg3); + break; + case FINC_PV_DIALOG: + calc_pv(equation, &result, arg1, arg2, arg3); + break; + case FINC_RATE_DIALOG: + calc_rate(equation, &result, arg1, arg2, arg3); + break; + case FINC_SLN_DIALOG: + calc_sln(equation, &result, arg1, arg2, arg3); + break; + case FINC_SYD_DIALOG: + calc_syd(equation, &result, arg1, arg2, arg3, arg4); + break; + case FINC_TERM_DIALOG: + calc_term(equation, &result, arg1, arg2, arg3); + break; + } + math_equation_set_number(equation, &result); +} |