SGEMV/DGEMV/CGEMV/ZGEMV | Matrix-vector multiply |
Example 1 Form the REAL*4 matrix-vector product y = Ax, where A is a 9-by-6 real matrix stored in an array A whose dimensions are 10-by-10, x is a real vector 6 elements long stored in an array X of dimension 10, and y is a real vector 9 elements long stored in an array Y, also of dimension 10.
CHARACTER*1 TRANS | | | | | |
INTEGER*4 | M,N,LDA,INCX,INCY | | | | | |
REAL*4 | ALPHA,BETA,A(10,10),X(10),Y(10) | | |
TRANS = ’N’ | | | | | | |
M = 9 | | | | | | |
N = 6 | | | | | | |
ALPHA = 1.0 | | | | | | |
BETA = 0.0 | | | | | | |
LDA = 10 | | | | | | |
INCX = 1 | | | | | | |
INCY = 1 | | | | | | |
CALL SGEMV (TRANS,M,N,ALPHA,A,LDA,X,INCX,BETA,Y,INCY) |
Example 2 Form the REAL*8 matrix-vector product y = | 1 | T | x , where | ρ | is a real |
-- y – ρ A | | |
| | 2 | | | | |
scalar, A is a 6-by-9 real matrix stored in an array A whose dimensions are
10-by-10, x is a real vector 6 elements long stored in an array X of dimension 10, and y is a real vector 9 elements long stored in an array Y, also of dimension 10.
INTEGER*4 | M,N,LDA |
REAL*8 | RHO,A(10,10),X(10),Y(10) |
M = 9 | |
N = | 6 | |
LDA | = 10 | |
CALL DGEMV (’TRANSPOSE’,M,N,-RHO,A,LDA,X,1,0.5D0,Y,1)
