/*============================================================================ WCSLIB 4.20 - an implementation of the FITS WCS standard. Copyright (C) 1995-2013, Mark Calabretta This file is part of WCSLIB. WCSLIB is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with WCSLIB. If not, see http://www.gnu.org/licenses. Direct correspondence concerning WCSLIB to mark@calabretta.id.au Author: Mark Calabretta, Australia Telescope National Facility, CSIRO. http://www.atnf.csiro.au/people/Mark.Calabretta $Id: lin.h,v 4.20 2013/12/18 05:42:49 mcalabre Exp $ *============================================================================= * * WCSLIB 4.20 - C routines that implement the FITS World Coordinate System * (WCS) standard. Refer to * * "Representations of world coordinates in FITS", * Greisen, E.W., & Calabretta, M.R. 2002, A&A, 395, 1061 (Paper I) * * Refer to the README file provided with WCSLIB for an overview of the * library. * * * Summary of the lin routines * --------------------------- * These routines apply the linear transformation defined by the FITS WCS * standard. They are based on the linprm struct which contains all * information needed for the computations. The struct contains some members * that must be set by the user, and others that are maintained by these * routines, somewhat like a C++ class but with no encapsulation. * * Three routines, linini(), lincpy(), and linfree() are provided to manage the * linprm struct, and another, linprt(), prints its contents. * * A setup routine, linset(), computes intermediate values in the linprm struct * from parameters in it that were supplied by the user. The struct always * needs to be set up by linset() but need not be called explicitly - refer to * the explanation of linprm::flag. * * linp2x() and linx2p() implement the WCS linear transformations. * * An auxiliary matrix inversion routine, matinv(), is included. It uses * LU-triangular factorization with scaled partial pivoting. * * * linini() - Default constructor for the linprm struct * ---------------------------------------------------- * linini() allocates memory for arrays in a linprm struct and sets all members * of the struct to default values. * * PLEASE NOTE: every linprm struct should be initialized by linini(), possibly * repeatedly. On the first invokation, and only the first invokation, * linprm::flag must be set to -1 to initialize memory management, regardless * of whether linini() will actually be used to allocate memory. * * Given: * alloc int If true, allocate memory unconditionally for arrays in * the linprm struct. * * If false, it is assumed that pointers to these arrays * have been set by the user except if they are null * pointers in which case memory will be allocated for * them regardless. (In other words, setting alloc true * saves having to initalize these pointers to zero.) * * naxis int The number of world coordinate axes, used to determine * array sizes. * * Given and returned: * lin struct linprm* * Linear transformation parameters. Note that, in order * to initialize memory management linprm::flag should be * set to -1 when lin is initialized for the first time * (memory leaks may result if it had already been * initialized). * * Function return value: * int Status return value: * 0: Success. * 1: Null linprm pointer passed. * 2: Memory allocation failed. * * For returns > 1, a detailed error message is set in * linprm::err if enabled, see wcserr_enable(). * * * lincpy() - Copy routine for the linprm struct * --------------------------------------------- * lincpy() does a deep copy of one linprm struct to another, using linini() to * allocate memory for its arrays if required. Only the "information to be * provided" part of the struct is copied; a call to linset() is required to * initialize the remainder. * * Given: * alloc int If true, allocate memory for the crpix, pc, and cdelt * arrays in the destination. Otherwise, it is assumed * that pointers to these arrays have been set by the * user except if they are null pointers in which case * memory will be allocated for them regardless. * * linsrc const struct linprm* * Struct to copy from. * * Given and returned: * lindst struct linprm* * Struct to copy to. linprm::flag should be set to -1 * if lindst was not previously initialized (memory leaks * may result if it was previously initialized). * * Function return value: * int Status return value: * 0: Success. * 1: Null linprm pointer passed. * 2: Memory allocation failed. * * For returns > 1, a detailed error message is set in * linprm::err if enabled, see wcserr_enable(). * * * linfree() - Destructor for the linprm struct * -------------------------------------------- * linfree() frees memory allocated for the linprm arrays by linini() and/or * linset(). linini() keeps a record of the memory it allocates and linfree() * will only attempt to free this. * * PLEASE NOTE: linfree() must not be invoked on a linprm struct that was not * initialized by linini(). * * Given: * lin struct linprm* * Linear transformation parameters. * * Function return value: * int Status return value: * 0: Success. * 1: Null linprm pointer passed. * * * linprt() - Print routine for the linprm struct * ---------------------------------------------- * linprt() prints the contents of a linprm struct using wcsprintf(). Mainly * intended for diagnostic purposes. * * Given: * lin const struct linprm* * Linear transformation parameters. * * Function return value: * int Status return value: * 0: Success. * 1: Null linprm pointer passed. * * * linset() - Setup routine for the linprm struct * ---------------------------------------------- * linset(), if necessary, allocates memory for the linprm::piximg and * linprm::imgpix arrays and sets up the linprm struct according to information * supplied within it - refer to the explanation of linprm::flag. * * Note that this routine need not be called directly; it will be invoked by * linp2x() and linx2p() if the linprm::flag is anything other than a * predefined magic value. * * Given and returned: * lin struct linprm* * Linear transformation parameters. * * Function return value: * int Status return value: * 0: Success. * 1: Null linprm pointer passed. * 2: Memory allocation failed. * 3: PCi_ja matrix is singular. * * For returns > 1, a detailed error message is set in * linprm::err if enabled, see wcserr_enable(). * * * linp2x() - Pixel-to-world linear transformation * ----------------------------------------------- * linp2x() transforms pixel coordinates to intermediate world coordinates. * * Given and returned: * lin struct linprm* * Linear transformation parameters. * * Given: * ncoord, * nelem int The number of coordinates, each of vector length nelem * but containing lin.naxis coordinate elements. * * pixcrd const double[ncoord][nelem] * Array of pixel coordinates. * * Returned: * imgcrd double[ncoord][nelem] * Array of intermediate world coordinates. * * Function return value: * int Status return value: * 0: Success. * 1: Null linprm pointer passed. * 2: Memory allocation failed. * 3: PCi_ja matrix is singular. * * For returns > 1, a detailed error message is set in * linprm::err if enabled, see wcserr_enable(). * * * linx2p() - World-to-pixel linear transformation * ----------------------------------------------- * linx2p() transforms intermediate world coordinates to pixel coordinates. * * Given and returned: * lin struct linprm* * Linear transformation parameters. * * Given: * ncoord, * nelem int The number of coordinates, each of vector length nelem * but containing lin.naxis coordinate elements. * * imgcrd const double[ncoord][nelem] * Array of intermediate world coordinates. * * Returned: * pixcrd double[ncoord][nelem] * Array of pixel coordinates. * * int Status return value: * 0: Success. * 1: Null linprm pointer passed. * 2: Memory allocation failed. * 3: PCi_ja matrix is singular. * * For returns > 1, a detailed error message is set in * linprm::err if enabled, see wcserr_enable(). * * * linprm struct - Linear transformation parameters * ------------------------------------------------ * The linprm struct contains all of the information required to perform a * linear transformation. It consists of certain members that must be set by * the user ("given") and others that are set by the WCSLIB routines * ("returned"). * * int flag * (Given and returned) This flag must be set to zero whenever any of the * following members of the linprm struct are set or modified: * * - linprm::naxis (q.v., not normally set by the user), * - linprm::pc, * - linprm::cdelt. * * This signals the initialization routine, linset(), to recompute the * returned members of the linprm struct. linset() will reset flag to * indicate that this has been done. * * PLEASE NOTE: flag should be set to -1 when linini() is called for the * first time for a particular linprm struct in order to initialize memory * management. It must ONLY be used on the first initialization otherwise * memory leaks may result. * * int naxis * (Given or returned) Number of pixel and world coordinate elements. * * If linini() is used to initialize the linprm struct (as would normally * be the case) then it will set naxis from the value passed to it as a * function argument. The user should not subsequently modify it. * * double *crpix * (Given) Pointer to the first element of an array of double containing * the coordinate reference pixel, CRPIXja. * * double *pc * (Given) Pointer to the first element of the PCi_ja (pixel coordinate) * transformation matrix. The expected order is * = struct linprm lin; = lin.pc = {PC1_1, PC1_2, PC2_1, PC2_2}; * * This may be constructed conveniently from a 2-D array via * = double m[2][2] = {{PC1_1, PC1_2}, = {PC2_1, PC2_2}}; * * which is equivalent to * = double m[2][2]; = m[0][0] = PC1_1; = m[0][1] = PC1_2; = m[1][0] = PC2_1; = m[1][1] = PC2_2; * * The storage order for this 2-D array is the same as for the 1-D array, * whence * = lin.pc = *m; * * would be legitimate. * * double *cdelt * (Given) Pointer to the first element of an array of double containing * the coordinate increments, CDELTia. * * int unity * (Returned) True if the linear transformation matrix is unity. * * int padding * (An unused variable inserted for alignment purposes only.) * * double *piximg * (Returned) Pointer to the first element of the matrix containing the * product of the CDELTia diagonal matrix and the PCi_ja matrix. * * double *imgpix * (Returned) Pointer to the first element of the inverse of the * linprm::piximg matrix. * * struct wcserr *err * (Returned) If enabled, when an error status is returned this struct * contains detailed information about the error, see wcserr_enable(). * * int i_naxis * (For internal use only.) * int m_flag * (For internal use only.) * int m_naxis * (For internal use only.) * int m_padding * (For internal use only.) * double *m_crpix * (For internal use only.) * double *m_pc * (For internal use only.) * double *m_cdelt * (For internal use only.) * void *padding2 * (For internal use only.) * * * Global variable: const char *lin_errmsg[] - Status return messages * ------------------------------------------------------------------ * Error messages to match the status value returned from each function. * *===========================================================================*/ #ifndef WCSLIB_LIN #define WCSLIB_LIN #include "wcserr.h" #ifdef __cplusplus extern "C" { #endif extern const char *lin_errmsg[]; enum lin_errmsg_enum { LINERR_SUCCESS = 0, /* Success. */ LINERR_NULL_POINTER = 1, /* Null linprm pointer passed. */ LINERR_MEMORY = 2, /* Memory allocation failed. */ LINERR_SINGULAR_MTX = 3 /* PCi_ja matrix is singular. */ }; struct linprm { /* Initialization flag (see the prologue above). */ /*------------------------------------------------------------------------*/ int flag; /* Set to zero to force initialization. */ /* Parameters to be provided (see the prologue above). */ /*------------------------------------------------------------------------*/ int naxis; /* The number of axes, given by NAXIS. */ double *crpix; /* CRPIXja keywords for each pixel axis. */ double *pc; /* PCi_ja linear transformation matrix. */ double *cdelt; /* CDELTia keywords for each coord axis. */ /* Information derived from the parameters supplied. */ /*------------------------------------------------------------------------*/ double *piximg; /* Product of CDELTia and PCi_ja matrices. */ double *imgpix; /* Inverse of the piximg matrix. */ int unity; /* True if the PCi_ja matrix is unity. */ /* Error handling */ /*------------------------------------------------------------------------*/ int padding; /* (Dummy inserted for alignment purposes.) */ struct wcserr *err; /* Private - the remainder are for memory management. */ /*------------------------------------------------------------------------*/ int i_naxis; int m_flag, m_naxis, m_padding; double *m_crpix, *m_pc, *m_cdelt; void *padding2; }; /* Size of the linprm struct in int units, used by the Fortran wrappers. */ #define LINLEN (sizeof(struct linprm)/sizeof(int)) int linini(int alloc, int naxis, struct linprm *lin); int lincpy(int alloc, const struct linprm *linsrc, struct linprm *lindst); int linfree(struct linprm *lin); int linprt(const struct linprm *lin); int linset(struct linprm *lin); int linp2x(struct linprm *lin, int ncoord, int nelem, const double pixcrd[], double imgcrd[]); int linx2p(struct linprm *lin, int ncoord, int nelem, const double imgcrd[], double pixcrd[]); int matinv(int n, const double mat[], double inv[]); /* Deprecated. */ #define linini_errmsg lin_errmsg #define lincpy_errmsg lin_errmsg #define linfree_errmsg lin_errmsg #define linprt_errmsg lin_errmsg #define linset_errmsg lin_errmsg #define linp2x_errmsg lin_errmsg #define linx2p_errmsg lin_errmsg #ifdef __cplusplus } #endif #endif /* WCSLIB_LIN */