void mtxmg_c ( const void * m1,
const void * m2,
void * mout )
Multiply the transpose of a matrix with another matrix,
both of arbitrary size. (The dimensions of the matrices must be
compatible with this multiplication.)
VARIABLE I/O DESCRIPTION
-------- --- --------------------------------------------------
m1 I nr1r2 X ncol1 double precision matrix.
m2 I nr1r2 X ncol2 double precision matrix.
ncol1 I Column dimension of m1 and row dimension of mout.
nr1r2 I Row dimension of m1 and m2.
ncol2 I Column dimension of m2 (and also mout).
mout O Transpose of m1 times m2.
m1 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.
ncol1 is the number of columns in m1 and the number of rows of
nr1r2 is the number of rows in both m1 and (by necessity) m2.
ncol2 is the number of columns in both m2 and mout.
mout mout is the product matrix defined as the transpose of
m1 times m2, that is
mout = (m1) x (m2)
where the superscript t denotes the transpose of m1.
mout is a double precision matrix of dimension ncol1 x
mout may overwrite m1 or m2. Note that this capability
does not exist in the Fortran version of SPICELIB; in the
Fortran version, the output must not overwrite either
1) If dynamic allocation of memory fails, the error
SPICE(MEMALLOCFAILED) is signalled.
The code reflects precisely the following mathematical expression
For each value of the subscript i from 1 to ncol1, and j from 1
mout(i,j) = Summation from k=1 to nr1r2 of m1(k,i) * m2(k,j)
1) Suppose that m1 = | 1 2 3 0 |
| 1 1 1 1 |
and that m2 = | 1 2 3 |
| 0 0 0 |
Then calling mtxmg_c as shown
mtxmg_c ( m1, m2, 4, 2, 3, mout )
will yield the following value for mout:
| 1 2 3 |
mout = | 2 4 6 |
| 3 6 9 |
| 0 0 0 |
1) No error checking is performed to prevent numeric overflow or
2) No error checking performed to determine if the input and
output matrices have, in fact, been correctly dimensioned.
N.J. Bachman (JPL)
W.M. Owen (JPL)
-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)
matrix transpose times matrix n-dimensional_case