mtxmg_c |

Table of contents## Proceduremtxmg_c ( Matrix transpose times matrix, general dimension ) void mtxmg_c ( const void * m1, const void * m2, SpiceInt nc1, SpiceInt nr1r2, SpiceInt nc2, void * mout ) ## AbstractMultiply the transpose of a matrix with another matrix, both of arbitrary size. (The dimensions of the matrices must be compatible with this multiplication.) ## Required_ReadingNone. ## KeywordsMATRIX ## Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- m1 I nr1r2 X nc1 double precision matrix. m2 I nr1r2 X nc2 double precision matrix. nc1 I Column dimension of `m1' and row dimension of `mout'. nr1r2 I Row dimension of `m1' and `m2'. nc2 I Column dimension of `m2' (and also `mout'). mout O Transpose of `m1' times `m2'. ## Detailed_Inputm1 is any double precision matrix of arbitrary size. m2 is any double precision matrix of arbitrary size. The number of rows in `m2' must match the number of rows in `m1'. nc1 is the number of columns in `m1' and the number of rows of `mout'. nr1r2 is the number of rows in both `m1' and (by necessity) `m2'. nc2 is the number of columns in both `m2' and `mout'. ## Detailed_Outputmout is the product matrix defined as the transpose of `m1' times `m2', that is t mout = (m1) x (m2) where the superscript `t' denotes the transpose of `m1'. `mout' is a double precision matrix of dimension nc1 x nc2. `mout' may overwrite `m1' or `m2'. ## ParametersNone. ## Exceptions1) If nr1r2 < 0, the elements of the matrix `mout' are set equal to zero. 2) If memory cannot be allocated to create the temporary matrix required for the execution of the routine, the error SPICE(MALLOCFAILED) is signaled. ## FilesNone. ## ParticularsThe code reflects precisely the following mathematical expression For each value of the subscript `i' from 1 to `nc1', and `j' from 1 to `nc2': mout(i,j) = Summation from k=1 to nr1r2 of m1(k,i) * m2(k,j) ## ExamplesThe numerical results shown for this example may differ across platforms. The results depend on the SPICE kernels used as input, the compiler and supporting libraries, and the machine specific arithmetic implementation. 1) Given a 2x4 and a 2x3 matrices, multiply the transpose of the first matrix by the second one. Example code begins here. /. Program mtxmg_ex1 ./ #include <stdio.h> #include "SpiceUsr.h" int main( ) { /. Local variables. ./ SpiceDouble mout [4][3]; SpiceInt i; /. Define `m1' and `m2'. ./ SpiceDouble m1 [2][4] = { { 1.0, 2.0, 3.0, 0.0 }, { 1.0, 1.0, 1.0, 0.0 } }; SpiceDouble m2 [2][3] = { { 1.0, 2.0, 3.0 }, { 0.0, 0.0, 0.0 } }; /. Multiply the transpose of `m1' by `m2'. ./ ## Restrictions1) No error checking is performed to prevent numeric overflow or underflow. 2) No error checking performed to determine if the input and output matrices have, in fact, been correctly dimensioned. ## Literature_ReferencesNone. ## Author_and_InstitutionN.J. Bachman (JPL) J. Diaz del Rio (ODC Space) W.M. Owen (JPL) E.D. Wright (JPL) ## Version-CSPICE Version 1.3.0, 10-AUG-2021 (JDR) Changed the input argument names "ncol1" and "ncol2" to "nc1" and "nc2" for consistency with other routines. Updated short error message for consistency within CSPICE wrapper interface: MEMALLOCFAILED -> MALLOCFAILED. Edited the header to comply with NAIF standard. Added complete code example based on the existing example. Added entry #1 to -Exceptions section. -CSPICE Version 1.2.2, 16-JAN-2008 (EDW) Corrected typos in header titles: Detailed Input to -Detailed_Input Detailed Output to -Detailed_Output -CSPICE Version 1.2.1, 10-NOV-2006 (EDW) Added -Parameters section header. -CSPICE Version 1.2.0, 28-AUG-2001 (NJB) Const-qualified input arrays. -CSPICE Version 1.0.0, 16-APR-1999 (NJB) (WMO) ## Index_Entriesmatrix transpose times matrix n-dimensional_case |

Fri Dec 31 18:41:09 2021