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/*============================================================================
*
* WCSLIB 4.2 - an implementation of the FITS WCS standard.
* Copyright (C) 1995-2005, Mark Calabretta
*
* WCSLIB 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.
*
* WCSLIB 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 WCSLIB; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
*
* Correspondence concerning WCSLIB may be directed to:
* Internet email: mcalabre@atnf.csiro.au
* Postal address: Dr. Mark Calabretta
* Australia Telescope National Facility, CSIRO
* PO Box 76
* Epping NSW 1710
* AUSTRALIA
*
* Author: Mark Calabretta, Australia Telescope National Facility
* http://www.atnf.csiro.au/~mcalabre/index.html
* $Id: log.c,v 4.2 2005/09/21 13:21:57 cal103 Exp $
*===========================================================================*/
#include <math.h>
#include "log.h"
/* Map status return value to message. */
const char *log_errmsg[] = {
"Success",
"",
"Invalid log-coordinate reference value",
"One or more of the x coordinates were invalid"};
/*--------------------------------------------------------------------------*/
int logx2s(
double crval,
int nx,
int sx,
int slogc,
const double x[],
double logc[],
int stat[])
{
register int ix;
register int *statp;
register const double *xp;
register double *logcp;
if (crval <= 0.0) {
return 2;
}
xp = x;
logcp = logc;
statp = stat;
for (ix = 0; ix < nx; ix++, xp += sx, logcp += slogc) {
*logcp = crval * exp((*xp) / crval);
*(statp++) = 0;
}
return 0;
}
/*--------------------------------------------------------------------------*/
int logs2x(
double crval,
int nlogc,
int slogc,
int sx,
const double logc[],
double x[],
int stat[])
{
int status;
register int ilogc;
register int *statp;
register const double *logcp;
register double *xp;
if (crval <= 0.0) {
return 2;
}
xp = x;
logcp = logc;
statp = stat;
status = 0;
for (ilogc = 0; ilogc < nlogc; ilogc++, logcp += slogc, xp += sx) {
if (*logcp > 0.0) {
*xp = crval * log(*logcp / crval);
*(statp++) = 0;
} else {
*(statp++) = 1;
status = 4;
}
}
return status;
}
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