OpenLibm/slatec/dprvec.f
Viral B. Shah c977aa998f Add Makefile.extras to build libopenlibm-extras.
Replace amos with slatec
2012-12-31 16:37:05 -05:00

34 lines
1,011 B
Fortran

*DECK DPRVEC
DOUBLE PRECISION FUNCTION DPRVEC (M, U, V)
C***BEGIN PROLOGUE DPRVEC
C***SUBSIDIARY
C***PURPOSE Subsidiary to DBVSUP
C***LIBRARY SLATEC
C***TYPE DOUBLE PRECISION (PRVEC-S, DPRVEC-D)
C***AUTHOR Watts, H. A., (SNLA)
C***DESCRIPTION
C
C This subroutine computes the inner product of a vector U
C with the imaginary product or mate vector corresponding to V.
C
C***SEE ALSO DBVSUP
C***ROUTINES CALLED DDOT
C***REVISION HISTORY (YYMMDD)
C 750601 DATE WRITTEN
C 890831 Modified array declarations. (WRB)
C 890831 REVISION DATE from Version 3.2
C 891214 Prologue converted to Version 4.0 format. (BAB)
C 900328 Added TYPE section. (WRB)
C 910722 Updated AUTHOR section. (ALS)
C***END PROLOGUE DPRVEC
C
DOUBLE PRECISION DDOT
INTEGER M, N, NP
DOUBLE PRECISION U(*), V(*), VP
C***FIRST EXECUTABLE STATEMENT DPRVEC
N = M/2
NP = N + 1
VP = DDOT(N,U(1),1,V(NP),1)
DPRVEC = DDOT(N,U(NP),1,V(1),1) - VP
RETURN
END