OpenLibm/slatec/c1merg.f
Viral B. Shah c977aa998f Add Makefile.extras to build libopenlibm-extras.
Replace amos with slatec
2012-12-31 16:37:05 -05:00

68 lines
2 KiB
Fortran

*DECK C1MERG
SUBROUTINE C1MERG (TCOS, I1, M1, I2, M2, I3)
C***BEGIN PROLOGUE C1MERG
C***SUBSIDIARY
C***PURPOSE Merge two strings of complex numbers. Each string is
C ascending by the real part.
C***LIBRARY SLATEC
C***TYPE COMPLEX (S1MERG-S, D1MERG-D, C1MERG-C, I1MERG-I)
C***AUTHOR (UNKNOWN)
C***DESCRIPTION
C
C This subroutine merges two ascending strings of numbers in the
C array TCOS. The first string is of length M1 and starts at
C TCOS(I1+1). The second string is of length M2 and starts at
C TCOS(I2+1). The merged string goes into TCOS(I3+1). The ordering
C is on the real part.
C
C***SEE ALSO CMGNBN
C***ROUTINES CALLED CCOPY
C***REVISION HISTORY (YYMMDD)
C 801001 DATE WRITTEN
C 891214 Prologue converted to Version 4.0 format. (BAB)
C 900402 Added TYPE section. (WRB)
C 910408 Modified to use IF-THEN-ELSE. Make it look like MERGE
C which was modified earlier due to compiler problems on
C the IBM RS6000. (RWC)
C 920130 Code name changed from CMPMRG to C1MERG. (WRB)
C***END PROLOGUE C1MERG
INTEGER I1, I2, I3, M1, M2
COMPLEX TCOS(*)
C
INTEGER J1, J2, J3
C
C***FIRST EXECUTABLE STATEMENT C1MERG
IF (M1.EQ.0 .AND. M2.EQ.0) RETURN
C
IF (M1.EQ.0 .AND. M2.NE.0) THEN
CALL CCOPY (M2, TCOS(I2+1), 1, TCOS(I3+1), 1)
RETURN
ENDIF
C
IF (M1.NE.0 .AND. M2.EQ.0) THEN
CALL CCOPY (M1, TCOS(I1+1), 1, TCOS(I3+1), 1)
RETURN
ENDIF
C
J1 = 1
J2 = 1
J3 = 1
C
10 IF (REAL(TCOS(J1+I1)) .LE. REAL(TCOS(I2+J2))) THEN
TCOS(I3+J3) = TCOS(I1+J1)
J1 = J1+1
IF (J1 .GT. M1) THEN
CALL CCOPY (M2-J2+1, TCOS(I2+J2), 1, TCOS(I3+J3+1), 1)
RETURN
ENDIF
ELSE
TCOS(I3+J3) = TCOS(I2+J2)
J2 = J2+1
IF (J2 .GT. M2) THEN
CALL CCOPY (M1-J1+1, TCOS(I1+J1), 1, TCOS(I3+J3+1), 1)
RETURN
ENDIF
ENDIF
J3 = J3+1
GO TO 10
END