mirror of
https://git.planet-casio.com/Lephenixnoir/OpenLibm.git
synced 2025-01-01 06:23:39 +01:00
41 lines
1.2 KiB
Fortran
41 lines
1.2 KiB
Fortran
*DECK ZABS
|
|
DOUBLE PRECISION FUNCTION ZABS (ZR, ZI)
|
|
C***BEGIN PROLOGUE ZABS
|
|
C***SUBSIDIARY
|
|
C***PURPOSE Subsidiary to ZBESH, ZBESI, ZBESJ, ZBESK, ZBESY, ZAIRY and
|
|
C ZBIRY
|
|
C***LIBRARY SLATEC
|
|
C***TYPE ALL (ZABS-A)
|
|
C***AUTHOR Amos, D. E., (SNL)
|
|
C***DESCRIPTION
|
|
C
|
|
C ZABS COMPUTES THE ABSOLUTE VALUE OR MAGNITUDE OF A DOUBLE
|
|
C PRECISION COMPLEX VARIABLE CMPLX(ZR,ZI)
|
|
C
|
|
C***SEE ALSO ZAIRY, ZBESH, ZBESI, ZBESJ, ZBESK, ZBESY, ZBIRY
|
|
C***ROUTINES CALLED (NONE)
|
|
C***REVISION HISTORY (YYMMDD)
|
|
C 830501 DATE WRITTEN
|
|
C 910415 Prologue converted to Version 4.0 format. (BAB)
|
|
C***END PROLOGUE ZABS
|
|
DOUBLE PRECISION ZR, ZI, U, V, Q, S
|
|
C***FIRST EXECUTABLE STATEMENT ZABS
|
|
U = ABS(ZR)
|
|
V = ABS(ZI)
|
|
S = U + V
|
|
C-----------------------------------------------------------------------
|
|
C S*1.0D0 MAKES AN UNNORMALIZED UNDERFLOW ON CDC MACHINES INTO A
|
|
C TRUE FLOATING ZERO
|
|
C-----------------------------------------------------------------------
|
|
S = S*1.0D+0
|
|
IF (S.EQ.0.0D+0) GO TO 20
|
|
IF (U.GT.V) GO TO 10
|
|
Q = U/V
|
|
ZABS = V*SQRT(1.D+0+Q*Q)
|
|
RETURN
|
|
10 Q = V/U
|
|
ZABS = U*SQRT(1.D+0+Q*Q)
|
|
RETURN
|
|
20 ZABS = 0.0D+0
|
|
RETURN
|
|
END
|