packad |
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ProcedurePACKAD ( Pack a double precision array ) SUBROUTINE PACKAD ( IN, . PACK, NPACK, . MAXOUT, NOUT, OUT ) AbstractPack the contents of a double precision array. That is, take a set of arbitrarily spaced elements from an input array, and make them adjacent elements in an output array. Required_ReadingNone. KeywordsARRAY ASSIGNMENT UTILITY DeclarationsIMPLICIT NONE DOUBLE PRECISION IN ( * ) INTEGER PACK ( * ) INTEGER NPACK INTEGER MAXOUT INTEGER NOUT DOUBLE PRECISION OUT ( * ) Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- IN I Input array. PACK I Indices of elements to be packed. NPACK I Number of indices. MAXOUT I Maximum number of elements in the output array. NOUT O Number of elements in the output array. OUT O Output array. Detailed_InputIN is the input array. PACK is the set of elements to be packed into the output array. PACK(i) is the index of the element in the input array that is to become the i'th element of the output array. NPACK is the number of elements to be packed into the output array. MAXOUT is the maximum number of elements to be packed into the output array. If NPACK is larger than MAXOUT, the extra items are ignored. Detailed_OutputNOUT is the number of elements in the output array. OUT is the output array. This array contains up to MAXOUT elements from the input array, located in the first NOUT elements of the array. ParametersNone. Exceptions1) If an element in the PACK array is less than 1, the error SPICE(INVALIDINDEX) is signaled. FilesNone. ParticularsThe indicated elements are moved from their current locations in the input array to consecutive positions in the output array. OUT( 1) = IN(PACK( 1)) OUT( 2) = IN(PACK( 2)) . . OUT(NOUT) = IN(PACK(NOUT)) NOUT is either NPACK or MAXOUT, whichever is smaller. ExamplesThe most common use for this routine is to remove unwanted items from an array or set of arrays. For example, suppose that the arrays NAME, CODE, RADIUS and MASS contain the names, NAIF integer ID codes, radii, and masses of a set of NSAT satellites. Suppose further that the user selects a subset of the original set of satellites from a menu of some sort. Let the indices of these satellites be the NSEL elements of the array SEL. The following sequence would remove the names, codes, etc., of the unselected satellites from the arrays. CALL PACKAC ( NAME, SEL, NSEL, NSAT, NOUT, NAME2 ) CALL PACKAI ( CODE, SEL, NSEL, NSAT, NOUT, CODE2 ) CALL PACKAD ( RADIUS, SEL, NSEL, NSAT, NOUT, RADIUS2 ) CALL PACKAD ( MASS, SEL, NSEL, NSAT, NOUT, MASS2 ) In the example above, suppose that NAME and PACK contain the following: NAME = 'MIMAS' PACK = 2, 4, 6, 7 'ENCELADUS' 'TETHYS' 'DIONE' 'RHEA' 'TITAN' 'HYPERION' 'IAPETUS' 'PHOEBE' Then, following the call to PACKAC, NOUT and NAME2 contain the following: NOUT = 4 NAME2 = 'ENCELADUS' 'DIONE' 'TITAN' 'HYPERION' RestrictionsNone. Literature_ReferencesNone. Author_and_InstitutionN.J. Bachman (JPL) J. Diaz del Rio (ODC Space) H.A. Neilan (JPL) W.L. Taber (JPL) I.M. Underwood (JPL) VersionSPICELIB Version 1.1.0, 20-AUG-2021 (JDR) Added IMPLICIT NONE statement. Edited the header to comply with NAIF standard. SPICELIB Version 1.0.2, 23-APR-2010 (NJB) Header correction: assertions that the output can overwrite the input have been removed. SPICELIB Version 1.0.1, 10-MAR-1992 (WLT) Comment section for permuted index source lines was added following the header. SPICELIB Version 1.0.0, 31-JAN-1990 (WLT) (IMU) (HAN) |
Fri Dec 31 18:36:37 2021