vrelg_c |

Table of contents## Procedurevrelg_c ( Vector relative difference, general dimension ) SpiceDouble vrelg_c ( ConstSpiceDouble * v1, ConstSpiceDouble * v2, SpiceInt ndim ) ## AbstractReturn the relative difference between two vectors of general dimension. ## Required_ReadingNone. ## KeywordsMATH VECTOR ## Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- v1, v2 I Input vectors. ndim I Dimension of `v1' and `v2'. The function returns the relative difference between two vectors of general dimension. ## Detailed_Inputv1, v2 are two vectors for which the relative difference is to be computed. ndim is the dimension of `v1' and `v2'. ## Detailed_OutputThe function returns the relative difference between the two input n-dimensional vectors `v1' and `v2'. It is defined as: || v1 - v2 || ## ParametersNone. ## ExceptionsError free. 1) If both `v1' and `v2' are zero vectors, then ## FilesNone. ## ParticularsThis function computes the relative difference between two vectors of general dimension as defined above. The function vrel_c may be used to find the relative difference for two 3-dimensional vectors. ## ExamplesThis example determines if the state of Jupiter, with respect to Voyager 2, for a set of times is the same for two different ephemeris files. Instead of insisting on absolute equality between the state vectors, the program will check if the relative difference between the vectors is greater than a fixed tolerance. #include "SpiceUsr.h" . . . /. The NAIF code for Jupiter is 599 and for Voyager 2 is -32. Set the tolerance to be 0.0005. ./ #define NUM 500 #define JUP 599 #define VG2 -32 #define TOL .0005 /. Local variables ./ SpiceDouble state1 [6][NUM]; SpiceDouble state2 [6][NUM]; SpiceDouble et [NUM]; SpiceDouble lt; SpiceDouble diff; SpiceInt i; . . . /. Load the first SPK file. ./ furnsh_c ( "VG2_SOURCE_1.BSP" ); /. Find the states for each time in the array ET. This example assumes that the SPK file can provide states for all of the times in the array. ./ for ( i = 0; i < NUM; i++ ) { spkez_c ( JUP, et[i], "J2000", "lt", VG2, state1[1][i], < ); } /. Unload the first file and load the second one. ./ unload_c ( "VG2_SOURCE_1.BSP" ); furnsh_c ( "VG2_SOURCE_2.BSP" ); /. Find the states from the new file. ./ for ( i = 0; i < NUM; i++ ) { spkez_c ( JUP, et[i], "J2000", "lt", VG2, state2[1][i], < ); } /. Now compare the two state vectors for each time. ./ for ( i = 0; i < NUM; i++ ) { diff = ## RestrictionsNone. ## Literature_ReferencesNone. ## Author_and_InstitutionN.J. Bachman (JPL) J. Diaz del Rio (ODC Space) J.M. Lynch (JPL) E.D. Wright (JPL) ## Version-CSPICE Version 1.0.1, 09-AUG-2021 (JDR) Edited the header to comply with NAIF standard. -CSPICE Version 1.0.0, 28-AUG-2001 (NJB) Include interface macro definition file SpiceZim.h. Made some minor updates and corrections in the code example. -CSPICE Version 1.0.0, 06-JUL-1999 (EDW) (JML) ## Index_Entriesrelative difference of n-dimensional vectors |

Fri Dec 31 18:41:15 2021