mirror of
https://github.com/levinsv/pgadmin3.git
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147 lines
3.8 KiB
C++
147 lines
3.8 KiB
C++
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/*
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* M_APM - mapmgues.c
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*
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* Copyright (C) 1999 - 2007 Michael C. Ring
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*
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* Permission to use, copy, and distribute this software and its
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* documentation for any purpose with or without fee is hereby granted,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation.
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*
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* Permission to modify the software is granted. Permission to distribute
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* the modified code is granted. Modifications are to be distributed by
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* using the file 'license.txt' as a template to modify the file header.
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* 'license.txt' is available in the official MAPM distribution.
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*
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* This software is provided "as is" without express or implied warranty.
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*/
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/*
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*
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* This file contains the functions that generate the initial
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* 'guesses' for the sqrt, cbrt, log, arcsin, and arccos functions.
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*/
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#include "pgAdmin3.h"
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#include "pgscript/utilities/mapm-lib/m_apm_lc.h"
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/****************************************************************************/
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void M_get_sqrt_guess(M_APM r, M_APM a)
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{
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char buf[48];
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double dd;
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m_apm_to_string(buf, 15, a);
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dd = atof(buf); /* sqrt algorithm actually finds 1/sqrt */
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m_apm_set_double(r, (1.0 / sqrt(dd)));
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}
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/****************************************************************************/
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/*
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* for cbrt, log, asin, and acos we induce an error of 10 ^ -5.
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* this enables the iterative routine to be more efficient
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* by knowing exactly how accurate the initial guess is.
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*
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* this also prevents some corner conditions where the iterative
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* functions may terminate too soon.
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*/
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/****************************************************************************/
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void M_get_cbrt_guess(M_APM r, M_APM a)
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{
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char buf[48];
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double dd;
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m_apm_to_string(buf, 15, a);
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dd = atof(buf);
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dd = log(dd) / 3.0; /* cbrt algorithm actually finds 1/cbrt */
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m_apm_set_double(r, (1.00001 / exp(dd)));
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}
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/****************************************************************************/
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void M_get_log_guess(M_APM r, M_APM a)
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{
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char buf[48];
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double dd;
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m_apm_to_string(buf, 15, a);
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dd = atof(buf);
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m_apm_set_double(r, (1.00001 * log(dd))); /* induce error of 10 ^ -5 */
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}
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/****************************************************************************/
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/*
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* the implementation of the asin & acos functions
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* guarantee that 'a' is always < 0.85, so it is
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* safe to multiply by a number > 1
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*/
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void M_get_asin_guess(M_APM r, M_APM a)
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{
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char buf[48];
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double dd;
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m_apm_to_string(buf, 15, a);
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dd = atof(buf);
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m_apm_set_double(r, (1.00001 * asin(dd))); /* induce error of 10 ^ -5 */
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}
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/****************************************************************************/
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void M_get_acos_guess(M_APM r, M_APM a)
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{
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char buf[48];
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double dd;
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m_apm_to_string(buf, 15, a);
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dd = atof(buf);
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m_apm_set_double(r, (1.00001 * acos(dd))); /* induce error of 10 ^ -5 */
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}
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/****************************************************************************/
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/*
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convert a C 'double' into an M_APM value.
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*/
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void m_apm_set_double(M_APM atmp, double dd)
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{
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char *cp, *p, *ps, buf[64];
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if (dd == 0.0) /* special case for 0 exactly */
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M_set_to_zero(atmp);
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else
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{
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sprintf(buf, "%.14E", dd);
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if ((cp = strstr(buf, "E")) == NULL)
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{
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M_apm_log_error_msg(M_APM_RETURN,
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"\'m_apm_set_double\', Invalid double input (likely a NAN or +/- INF)");
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M_set_to_zero(atmp);
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return;
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}
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if (atoi(cp + sizeof(char)) == 0)
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*cp = '\0';
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p = cp;
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while (TRUE)
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{
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p--;
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if (*p == '0' || *p == '.')
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*p = ' ';
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else
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break;
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}
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ps = buf;
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p = buf;
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while (TRUE)
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{
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if ((*p = *ps) == '\0')
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break;
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if (*ps++ != ' ')
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p++;
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}
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m_apm_set_string(atmp, buf);
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}
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}
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/****************************************************************************/
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