MXYTF

Multiplies a matrix A by the transpose of a matrix B, ABT.

Required Arguments

A — Real NRA by NCA rectangular matrix. (Input)

B — Real NRB by NCB rectangular matrix. (Input)

C — Real NRC by NCC rectangular matrix containing the transpose product ABT. (Output)

Optional Arguments

NRA — Number of rows in A. (Input)
Default: NRA = SIZE (A,1).

NCA — Number of columns in A. (Input)
Default: NCA = SIZE (A,2).

LDA — Leading dimension of A exactly as specified in the dimension statement of the calling program. (Input)
Default: LDA = SIZE (A,1).

NRB — Number of rows in B. (Input)
Default: NRB = SIZE (B,1).

NCB — Number of columns in B. (Input)
NCB must be the same as NCA.
Default: NCB = SIZE (B,2).

LDB — Leading dimension of B exactly as specified in the dimension statement of the calling program. (Input)
Default: LDB = SIZE (B,1).

NRC — Number of rows of C. (Input)
NRC must be equal to NRA.
Default: NRC = SIZE (C,1).

NCC — Number of columns of C. (Input)
NCC must be equal to NRB.
Default: NCC = SIZE (C,2).

LDC — Leading dimension of C exactly as specified in the dimension statement of the calling program. (Input)
Default: LDC = SIZE (C,1).

FORTRAN 90 Interface

Generic: CALL MXYTF (A, B, C [, …])

Specific: The specific interface names are S_MXYTF and D_MXYTF.

FORTRAN 77 Interface

Single: CALL MXYTF (NRA, NCA, A, LDA, NRB, NCB, B, LDB, NRC, NCC, C, LDC)

Double: The double precision name is DMXYTF.

Description

The routine MXYTF computes the real general matrix C = ABT given the real rectangular matrices A and B.

Example

Multiply a 3 × 4 real matrix by the transpose of a 3 × 4 real matrix. The output matrix will be a 3 × 3 real matrix.

 

USE MXYTF_INT

USE WRRRN_INT

 

IMPLICIT NONE

! Declare variables

INTEGER NCA, NCB, NCC, NRA, NRB, NRC

PARAMETER (NCA=4, NCB=4, NCC=3, NRA=3, NRB=3, NRC=3)

!

REAL A(NRA,NCA), B(NRB,NCB), C(NRC,NCC)

! Set values for A

! A = ( 1.0 0.0 2.0 0.0 )

! ( 3.0 4.0 -1.0 0.0 )

! ( 2.0 1.0 2.0 1.0 )

!

! Set values for B

! B = ( -1.0 2.0 0.0 2.0 )

! ( 3.0 0.0 -1.0 -1.0 )

! ( 0.0 5.0 2.0 5.0 )

!

DATA A/1.0, 3.0, 2.0, 0.0, 4.0, 1.0, 2.0, -1.0, 2.0, 0.0, 0.0, &

1.0/

DATA B/-1.0, 3.0, 0.0, 2.0, 0.0, 5.0, 0.0, -1.0, 2.0, 2.0, -1.0, &

5.0/

! Compute C = A*trans(B)

CALL MXYTF (A, B, C)

! Print results

CALL WRRRN ('C = A*trans(B)', C)

END

Output

 

C = A*trans(B)

1 2 3

1 -1.00 1.00 4.00

2 5.00 10.00 18.00

3 2.00 3.00 14.00