| C Derived from lapack |
| PROGRAM test |
| DOUBLE PRECISION DA |
| INTEGER I, N |
| DOUBLE PRECISION DX(9),DY(9) |
| |
| EXTERNAL DAXPY |
| N=5 |
| DA=1.0 |
| DATA DX/-2, -1, -3, -4, 1, 2, 10, 15, 14/ |
| DATA DY/0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0/ |
| CALL DAXPY (N,DA,DX,DY) |
| DO 10 I = 1, N |
| if (DX(I).ne.DY(I)) STOP 1 |
| 10 CONTINUE |
| STOP |
| END |
| |
| SUBROUTINE DAXPY(N,DA,DX,DY) |
| DOUBLE PRECISION DA |
| INTEGER N |
| DOUBLE PRECISION DX(*),DY(*) |
| INTEGER I,IX,IY,M,MP1 |
| INTRINSIC MOD |
| IF (N.LE.0) RETURN |
| 20 M = MOD(N,4) |
| IF (M.EQ.0) GO TO 40 |
| DO 30 I = 1,M |
| DY(I) = DY(I) + DA*DX(I) |
| 30 CONTINUE |
| IF (N.LT.4) RETURN |
| 40 MP1 = M + 1 |
| DO 50 I = MP1,N,4 |
| DY(I) = DY(I) + DA*DX(I) |
| DY(I+1) = DY(I+1) + DA*DX(I+1) |
| DY(I+2) = DY(I+2) + DA*DX(I+2) |
| DY(I+3) = DY(I+3) + DA*DX(I+3) |
| 50 CONTINUE |
| RETURN |
| END |
