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OpenLibm/slatec/cuni2.f
Viral B. Shah c977aa998f Add Makefile.extras to build libopenlibm-extras. 
Replace amos with slatec
2012-12-31 16:37:05 -05:00

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Fortran
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*DECK CUNI2
SUBROUTINE CUNI2 (Z, FNU, KODE, N, Y, NZ, NLAST, FNUL, TOL, ELIM,
+ ALIM)
C***BEGIN PROLOGUE CUNI2
C***SUBSIDIARY
C***PURPOSE Subsidiary to CBESI and CBESK
C***LIBRARY SLATEC
C***TYPE ALL (CUNI2-A, ZUNI2-A)
C***AUTHOR Amos, D. E., (SNL)
C***DESCRIPTION
C
C CUNI2 COMPUTES I(FNU,Z) IN THE RIGHT HALF PLANE BY MEANS OF
C UNIFORM ASYMPTOTIC EXPANSION FOR J(FNU,ZN) WHERE ZN IS Z*I
C OR -Z*I AND ZN IS IN THE RIGHT HALF PLANE ALSO.
C
C FNUL IS THE SMALLEST ORDER PERMITTED FOR THE ASYMPTOTIC
C EXPANSION. NLAST=0 MEANS ALL OF THE Y VALUES WERE SET.
C NLAST.NE.0 IS THE NUMBER LEFT TO BE COMPUTED BY ANOTHER
C FORMULA FOR ORDERS FNU TO FNU+NLAST-1 BECAUSE FNU+NLAST-1.LT.FNUL.
C Y(I)=CZERO FOR I=NLAST+1,N
C
C***SEE ALSO CBESI, CBESK
C***ROUTINES CALLED CAIRY, CUCHK, CUNHJ, CUOIK, R1MACH
C***REVISION HISTORY (YYMMDD)
C 830501 DATE WRITTEN
C 910415 Prologue converted to Version 4.0 format. (BAB)
C***END PROLOGUE CUNI2
COMPLEX AI, ARG, ASUM, BSUM, CFN, CI, CID, CIP, CONE, CRSC, CSCL,
* CSR, CSS, CY, CZERO, C1, C2, DAI, PHI, RZ, S1, S2, Y, Z, ZB,
* ZETA1, ZETA2, ZN, ZAR
REAL AARG, AIC, ALIM, ANG, APHI, ASCLE, AY, BRY, CAR, C2I, C2M,
* C2R, ELIM, FN, FNU, FNUL, HPI, RS1, SAR, TOL, YY, R1MACH
INTEGER I, IFLAG, IN, INU, J, K, KODE, N, NAI, ND, NDAI, NLAST,
* NN, NUF, NW, NZ, IDUM
DIMENSION BRY(3), Y(N), CIP(4), CSS(3), CSR(3), CY(2)
DATA CZERO,CONE,CI/(0.0E0,0.0E0),(1.0E0,0.0E0),(0.0E0,1.0E0)/
DATA CIP(1),CIP(2),CIP(3),CIP(4)/
1 (1.0E0,0.0E0), (0.0E0,1.0E0), (-1.0E0,0.0E0), (0.0E0,-1.0E0)/
DATA HPI, AIC /
1 1.57079632679489662E+00, 1.265512123484645396E+00/
C***FIRST EXECUTABLE STATEMENT CUNI2
NZ = 0
ND = N
NLAST = 0
C-----------------------------------------------------------------------
C COMPUTED VALUES WITH EXPONENTS BETWEEN ALIM AND ELIM IN MAG-
C NITUDE ARE SCALED TO KEEP INTERMEDIATE ARITHMETIC ON SCALE,
C EXP(ALIM)=EXP(ELIM)*TOL
C-----------------------------------------------------------------------
CSCL = CMPLX(1.0E0/TOL,0.0E0)
CRSC = CMPLX(TOL,0.0E0)
CSS(1) = CSCL
CSS(2) = CONE
CSS(3) = CRSC
CSR(1) = CRSC
CSR(2) = CONE
CSR(3) = CSCL
BRY(1) = 1.0E+3*R1MACH(1)/TOL
YY = AIMAG(Z)
C-----------------------------------------------------------------------
C ZN IS IN THE RIGHT HALF PLANE AFTER ROTATION BY CI OR -CI
C-----------------------------------------------------------------------
ZN = -Z*CI
ZB = Z
CID = -CI
INU = FNU
ANG = HPI*(FNU-INU)
CAR = COS(ANG)
SAR = SIN(ANG)
C2 = CMPLX(CAR,SAR)
ZAR = C2
IN = INU + N - 1
IN = MOD(IN,4)
C2 = C2*CIP(IN+1)
IF (YY.GT.0.0E0) GO TO 10
ZN = CONJG(-ZN)
ZB = CONJG(ZB)
CID = -CID
C2 = CONJG(C2)
10 CONTINUE
C-----------------------------------------------------------------------
C CHECK FOR UNDERFLOW AND OVERFLOW ON FIRST MEMBER
C-----------------------------------------------------------------------
FN = MAX(FNU,1.0E0)
CALL CUNHJ(ZN, FN, 1, TOL, PHI, ARG, ZETA1, ZETA2, ASUM, BSUM)
IF (KODE.EQ.1) GO TO 20
CFN = CMPLX(FNU,0.0E0)
S1 = -ZETA1 + CFN*(CFN/(ZB+ZETA2))
GO TO 30
20 CONTINUE
S1 = -ZETA1 + ZETA2
30 CONTINUE
RS1 = REAL(S1)
IF (ABS(RS1).GT.ELIM) GO TO 150
40 CONTINUE
NN = MIN(2,ND)
DO 90 I=1,NN
FN = FNU + (ND-I)
CALL CUNHJ(ZN, FN, 0, TOL, PHI, ARG, ZETA1, ZETA2, ASUM, BSUM)
IF (KODE.EQ.1) GO TO 50
CFN = CMPLX(FN,0.0E0)
AY = ABS(YY)
S1 = -ZETA1 + CFN*(CFN/(ZB+ZETA2)) + CMPLX(0.0E0,AY)
GO TO 60
50 CONTINUE
S1 = -ZETA1 + ZETA2
60 CONTINUE
C-----------------------------------------------------------------------
C TEST FOR UNDERFLOW AND OVERFLOW
C-----------------------------------------------------------------------
RS1 = REAL(S1)
IF (ABS(RS1).GT.ELIM) GO TO 120
IF (I.EQ.1) IFLAG = 2
IF (ABS(RS1).LT.ALIM) GO TO 70
C-----------------------------------------------------------------------
C REFINE TEST AND SCALE
C-----------------------------------------------------------------------
C-----------------------------------------------------------------------
APHI = ABS(PHI)
AARG = ABS(ARG)
RS1 = RS1 + ALOG(APHI) - 0.25E0*ALOG(AARG) - AIC
IF (ABS(RS1).GT.ELIM) GO TO 120
IF (I.EQ.1) IFLAG = 1
IF (RS1.LT.0.0E0) GO TO 70
IF (I.EQ.1) IFLAG = 3
70 CONTINUE
C-----------------------------------------------------------------------
C SCALE S1 TO KEEP INTERMEDIATE ARITHMETIC ON SCALE NEAR
C EXPONENT EXTREMES
C-----------------------------------------------------------------------
CALL CAIRY(ARG, 0, 2, AI, NAI, IDUM)
CALL CAIRY(ARG, 1, 2, DAI, NDAI, IDUM)
S2 = PHI*(AI*ASUM+DAI*BSUM)
C2R = REAL(S1)
C2I = AIMAG(S1)
C2M = EXP(C2R)*REAL(CSS(IFLAG))
S1 = CMPLX(C2M,0.0E0)*CMPLX(COS(C2I),SIN(C2I))
S2 = S2*S1
IF (IFLAG.NE.1) GO TO 80
CALL CUCHK(S2, NW, BRY(1), TOL)
IF (NW.NE.0) GO TO 120
80 CONTINUE
IF (YY.LE.0.0E0) S2 = CONJG(S2)
J = ND - I + 1
S2 = S2*C2
CY(I) = S2
Y(J) = S2*CSR(IFLAG)
C2 = C2*CID
90 CONTINUE
IF (ND.LE.2) GO TO 110
RZ = CMPLX(2.0E0,0.0E0)/Z
BRY(2) = 1.0E0/BRY(1)
BRY(3) = R1MACH(2)
S1 = CY(1)
S2 = CY(2)
C1 = CSR(IFLAG)
ASCLE = BRY(IFLAG)
K = ND - 2
FN = K
DO 100 I=3,ND
C2 = S2
S2 = S1 + CMPLX(FNU+FN,0.0E0)*RZ*S2
S1 = C2
C2 = S2*C1
Y(K) = C2
K = K - 1
FN = FN - 1.0E0
IF (IFLAG.GE.3) GO TO 100
C2R = REAL(C2)
C2I = AIMAG(C2)
C2R = ABS(C2R)
C2I = ABS(C2I)
C2M = MAX(C2R,C2I)
IF (C2M.LE.ASCLE) GO TO 100
IFLAG = IFLAG + 1
ASCLE = BRY(IFLAG)
S1 = S1*C1
S2 = C2
S1 = S1*CSS(IFLAG)
S2 = S2*CSS(IFLAG)
C1 = CSR(IFLAG)
100 CONTINUE
110 CONTINUE
RETURN
120 CONTINUE
IF (RS1.GT.0.0E0) GO TO 140
C-----------------------------------------------------------------------
C SET UNDERFLOW AND UPDATE PARAMETERS
C-----------------------------------------------------------------------
Y(ND) = CZERO
NZ = NZ + 1
ND = ND - 1
IF (ND.EQ.0) GO TO 110
CALL CUOIK(Z, FNU, KODE, 1, ND, Y, NUF, TOL, ELIM, ALIM)
IF (NUF.LT.0) GO TO 140
ND = ND - NUF
NZ = NZ + NUF
IF (ND.EQ.0) GO TO 110
FN = FNU + (ND-1)
IF (FN.LT.FNUL) GO TO 130
C FN = AIMAG(CID)
C J = NUF + 1
C K = MOD(J,4) + 1
C S1 = CIP(K)
C IF (FN.LT.0.0E0) S1 = CONJG(S1)
C C2 = C2*S1
IN = INU + ND - 1
IN = MOD(IN,4) + 1
C2 = ZAR*CIP(IN)
IF (YY.LE.0.0E0)C2=CONJG(C2)
GO TO 40
130 CONTINUE
NLAST = ND
RETURN
140 CONTINUE
NZ = -1
RETURN
150 CONTINUE
IF (RS1.GT.0.0E0) GO TO 140
NZ = N
DO 160 I=1,N
Y(I) = CZERO
160 CONTINUE
RETURN
END
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