gonum.org/v1/gonum@v0.14.0/mathext/internal/amos/amoslib/zbknu.f (about)

     1        SUBROUTINE ZBKNU(ZR, ZI, FNU, KODE, N, YR, YI, NZ, TOL, ELIM,
     2       * ALIM)
     3  C***BEGIN PROLOGUE  ZBKNU
     4  C***REFER TO  ZBESI,ZBESK,ZAIRY,ZBESH
     5  C
     6  C     ZBKNU COMPUTES THE K BESSEL FUNCTION IN THE RIGHT HALF Z PLANE.
     7  C
     8  C***ROUTINES CALLED  DGAMLN,I1MACH,D1MACH,ZKSCL,ZSHCH,ZUCHK,ZABS,ZDIV,
     9  C                    ZEXP,ZLOG,ZMLT,ZSQRT
    10  C***END PROLOGUE  ZBKNU
    11  C
    12        DOUBLE PRECISION AA, AK, ALIM, ASCLE, A1, A2, BB, BK, BRY, CAZ,
    13       * CBI, CBR, CC, CCHI, CCHR, CKI, CKR, COEFI, COEFR, CONEI, CONER,
    14       * CRSCR, CSCLR, CSHI, CSHR, CSI, CSR, CSRR, CSSR, CTWOR,
    15       * CZEROI, CZEROR, CZI, CZR, DNU, DNU2, DPI, ELIM, ETEST, FC, FHS,
    16       * FI, FK, FKS, FMUI, FMUR, FNU, FPI, FR, G1, G2, HPI, PI, PR, PTI,
    17       * PTR, P1I, P1R, P2I, P2M, P2R, QI, QR, RAK, RCAZ, RTHPI, RZI,
    18       * RZR, R1, S, SMUI, SMUR, SPI, STI, STR, S1I, S1R, S2I, S2R, TM,
    19       * TOL, TTH, T1, T2, YI, YR, ZI, ZR, DGAMLN, D1MACH, ZABS, ELM,
    20       * CELMR, ZDR, ZDI, AS, ALAS, HELIM, CYR, CYI
    21        INTEGER I, IFLAG, INU, K, KFLAG, KK, KMAX, KODE, KODED, N, NZ,
    22       * IDUM, I1MACH, J, IC, INUB, NW
    23        DIMENSION YR(N), YI(N), CC(8), CSSR(3), CSRR(3), BRY(3), CYR(2),
    24       * CYI(2)
    25  C     COMPLEX Z,Y,A,B,RZ,SMU,FU,FMU,F,FLRZ,CZ,S1,S2,CSH,CCH
    26  C     COMPLEX CK,P,Q,COEF,P1,P2,CBK,PT,CZERO,CONE,CTWO,ST,EZ,CS,DK
    27  C
    28        DATA KMAX / 30 /
    29        DATA CZEROR,CZEROI,CONER,CONEI,CTWOR,R1/
    30       1  0.0D0 , 0.0D0 , 1.0D0 , 0.0D0 , 2.0D0 , 2.0D0 /
    31        DATA DPI, RTHPI, SPI ,HPI, FPI, TTH /
    32       1     3.14159265358979324D0,       1.25331413731550025D0,
    33       2     1.90985931710274403D0,       1.57079632679489662D0,
    34       3     1.89769999331517738D0,       6.66666666666666666D-01/
    35        DATA CC(1), CC(2), CC(3), CC(4), CC(5), CC(6), CC(7), CC(8)/
    36       1     5.77215664901532861D-01,    -4.20026350340952355D-02,
    37       2    -4.21977345555443367D-02,     7.21894324666309954D-03,
    38       3    -2.15241674114950973D-04,    -2.01348547807882387D-05,
    39       4     1.13302723198169588D-06,     6.11609510448141582D-09/
    40  C
    41        CAZ = ZABS(CMPLX(ZR,ZI,kind=KIND(1.0D0)))
    42        CSCLR = 1.0D0/TOL
    43        CRSCR = TOL
    44        CSSR(1) = CSCLR
    45        CSSR(2) = 1.0D0
    46        CSSR(3) = CRSCR
    47        CSRR(1) = CRSCR
    48        CSRR(2) = 1.0D0
    49        CSRR(3) = CSCLR
    50        BRY(1) = 1.0D+3*D1MACH(1)/TOL
    51        BRY(2) = 1.0D0/BRY(1)
    52        BRY(3) = D1MACH(2)
    53        NZ = 0
    54        IFLAG = 0
    55        KODED = KODE
    56        RCAZ = 1.0D0/CAZ
    57        STR = ZR*RCAZ
    58        STI = -ZI*RCAZ
    59        RZR = (STR+STR)*RCAZ
    60        RZI = (STI+STI)*RCAZ
    61        INU = INT(SNGL(FNU+0.5D0))
    62        DNU = FNU - DBLE(FLOAT(INU))
    63        IF (DABS(DNU).EQ.0.5D0) GO TO 110
    64        DNU2 = 0.0D0
    65        IF (DABS(DNU).GT.TOL) DNU2 = DNU*DNU
    66        IF (CAZ.GT.R1) GO TO 110
    67  C-----------------------------------------------------------------------
    68  C     SERIES FOR CABS(Z).LE.R1
    69  C-----------------------------------------------------------------------
    70        FC = 1.0D0
    71        CALL ZLOG(RZR, RZI, SMUR, SMUI, IDUM)
    72        FMUR = SMUR*DNU
    73        FMUI = SMUI*DNU
    74        CALL ZSHCH(FMUR, FMUI, CSHR, CSHI, CCHR, CCHI)
    75        IF (DNU.EQ.0.0D0) GO TO 10
    76        FC = DNU*DPI
    77        FC = FC/DSIN(FC)
    78        SMUR = CSHR/DNU
    79        SMUI = CSHI/DNU
    80     10 CONTINUE
    81        A2 = 1.0D0 + DNU
    82  C-----------------------------------------------------------------------
    83  C     GAM(1-Z)*GAM(1+Z)=PI*Z/SIN(PI*Z), T1=1/GAM(1-DNU), T2=1/GAM(1+DNU)
    84  C-----------------------------------------------------------------------
    85        T2 = DEXP(-DGAMLN(A2,IDUM))
    86        T1 = 1.0D0/(T2*FC)
    87        IF (DABS(DNU).GT.0.1D0) GO TO 40
    88  C-----------------------------------------------------------------------
    89  C     SERIES FOR F0 TO RESOLVE INDETERMINACY FOR SMALL ABS(DNU)
    90  C-----------------------------------------------------------------------
    91        AK = 1.0D0
    92        S = CC(1)
    93        DO 20 K=2,8
    94          AK = AK*DNU2
    95          TM = CC(K)*AK
    96          S = S + TM
    97          IF (DABS(TM).LT.TOL) GO TO 30
    98     20 CONTINUE
    99     30 G1 = -S
   100        GO TO 50
   101     40 CONTINUE
   102        G1 = (T1-T2)/(DNU+DNU)
   103     50 CONTINUE
   104        G2 = (T1+T2)*0.5D0
   105        FR = FC*(CCHR*G1+SMUR*G2)
   106        FI = FC*(CCHI*G1+SMUI*G2)
   107        CALL ZEXP(FMUR, FMUI, STR, STI)
   108        PR = 0.5D0*STR/T2
   109        PI = 0.5D0*STI/T2
   110        CALL ZDIV(0.5D0, 0.0D0, STR, STI, PTR, PTI)
   111        QR = PTR/T1
   112        QI = PTI/T1
   113        S1R = FR
   114        S1I = FI
   115        S2R = PR
   116        S2I = PI
   117        AK = 1.0D0
   118        A1 = 1.0D0
   119        CKR = CONER
   120        CKI = CONEI
   121        BK = 1.0D0 - DNU2
   122        IF (INU.GT.0 .OR. N.GT.1) GO TO 80
   123  C-----------------------------------------------------------------------
   124  C     GENERATE K(FNU,Z), 0.0D0 .LE. FNU .LT. 0.5D0 AND N=1
   125  C-----------------------------------------------------------------------
   126        IF (CAZ.LT.TOL) GO TO 70
   127        CALL ZMLT(ZR, ZI, ZR, ZI, CZR, CZI)
   128        CZR = 0.25D0*CZR
   129        CZI = 0.25D0*CZI
   130        T1 = 0.25D0*CAZ*CAZ
   131     60 CONTINUE
   132        FR = (FR*AK+PR+QR)/BK
   133        FI = (FI*AK+PI+QI)/BK
   134        STR = 1.0D0/(AK-DNU)
   135        PR = PR*STR
   136        PI = PI*STR
   137        STR = 1.0D0/(AK+DNU)
   138        QR = QR*STR
   139        QI = QI*STR
   140        STR = CKR*CZR - CKI*CZI
   141        RAK = 1.0D0/AK
   142        CKI = (CKR*CZI+CKI*CZR)*RAK
   143        CKR = STR*RAK
   144        S1R = CKR*FR - CKI*FI + S1R
   145        S1I = CKR*FI + CKI*FR + S1I
   146        A1 = A1*T1*RAK
   147        BK = BK + AK + AK + 1.0D0
   148        AK = AK + 1.0D0
   149        IF (A1.GT.TOL) GO TO 60
   150     70 CONTINUE
   151        YR(1) = S1R
   152        YI(1) = S1I
   153        IF (KODED.EQ.1) RETURN
   154        CALL ZEXP(ZR, ZI, STR, STI)
   155        CALL ZMLT(S1R, S1I, STR, STI, YR(1), YI(1))
   156        RETURN
   157  C-----------------------------------------------------------------------
   158  C     GENERATE K(DNU,Z) AND K(DNU+1,Z) FOR FORWARD RECURRENCE
   159  C-----------------------------------------------------------------------
   160     80 CONTINUE
   161        IF (CAZ.LT.TOL) GO TO 100
   162        CALL ZMLT(ZR, ZI, ZR, ZI, CZR, CZI)
   163        CZR = 0.25D0*CZR
   164        CZI = 0.25D0*CZI
   165        T1 = 0.25D0*CAZ*CAZ
   166     90 CONTINUE
   167        FR = (FR*AK+PR+QR)/BK
   168        FI = (FI*AK+PI+QI)/BK
   169        STR = 1.0D0/(AK-DNU)
   170        PR = PR*STR
   171        PI = PI*STR
   172        STR = 1.0D0/(AK+DNU)
   173        QR = QR*STR
   174        QI = QI*STR
   175        STR = CKR*CZR - CKI*CZI
   176        RAK = 1.0D0/AK
   177        CKI = (CKR*CZI+CKI*CZR)*RAK
   178        CKR = STR*RAK
   179        S1R = CKR*FR - CKI*FI + S1R
   180        S1I = CKR*FI + CKI*FR + S1I
   181        STR = PR - FR*AK
   182        STI = PI - FI*AK
   183        S2R = CKR*STR - CKI*STI + S2R
   184        S2I = CKR*STI + CKI*STR + S2I
   185        A1 = A1*T1*RAK
   186        BK = BK + AK + AK + 1.0D0
   187        AK = AK + 1.0D0
   188        IF (A1.GT.TOL) GO TO 90
   189    100 CONTINUE
   190        KFLAG = 2
   191        A1 = FNU + 1.0D0
   192        AK = A1*DABS(SMUR)
   193        IF (AK.GT.ALIM) KFLAG = 3
   194        STR = CSSR(KFLAG)
   195        P2R = S2R*STR
   196        P2I = S2I*STR
   197        CALL ZMLT(P2R, P2I, RZR, RZI, S2R, S2I)
   198        S1R = S1R*STR
   199        S1I = S1I*STR
   200        IF (KODED.EQ.1) GO TO 210
   201        CALL ZEXP(ZR, ZI, FR, FI)
   202        CALL ZMLT(S1R, S1I, FR, FI, S1R, S1I)
   203        CALL ZMLT(S2R, S2I, FR, FI, S2R, S2I)
   204        GO TO 210
   205  C-----------------------------------------------------------------------
   206  C     IFLAG=0 MEANS NO UNDERFLOW OCCURRED
   207  C     IFLAG=1 MEANS AN UNDERFLOW OCCURRED- COMPUTATION PROCEEDS WITH
   208  C     KODED=2 AND A TEST FOR ON SCALE VALUES IS MADE DURING FORWARD
   209  C     RECURSION
   210  C-----------------------------------------------------------------------
   211    110 CONTINUE
   212        CALL ZSQRT(ZR, ZI, STR, STI)
   213        CALL ZDIV(RTHPI, CZEROI, STR, STI, COEFR, COEFI)
   214        KFLAG = 2
   215        IF (KODED.EQ.2) GO TO 120
   216        IF (ZR.GT.ALIM) GO TO 290
   217  C     BLANK LINE
   218        STR = DEXP(-ZR)*CSSR(KFLAG)
   219        STI = -STR*DSIN(ZI)
   220        STR = STR*DCOS(ZI)
   221        CALL ZMLT(COEFR, COEFI, STR, STI, COEFR, COEFI)
   222    120 CONTINUE
   223        IF (DABS(DNU).EQ.0.5D0) GO TO 300
   224  C-----------------------------------------------------------------------
   225  C     MILLER ALGORITHM FOR CABS(Z).GT.R1
   226  C-----------------------------------------------------------------------
   227        AK = DCOS(DPI*DNU)
   228        AK = DABS(AK)
   229        IF (AK.EQ.CZEROR) GO TO 300
   230        FHS = DABS(0.25D0-DNU2)
   231        IF (FHS.EQ.CZEROR) GO TO 300
   232  C-----------------------------------------------------------------------
   233  C     COMPUTE R2=F(E). IF CABS(Z).GE.R2, USE FORWARD RECURRENCE TO
   234  C     DETERMINE THE BACKWARD INDEX K. R2=F(E) IS A STRAIGHT LINE ON
   235  C     12.LE.E.LE.60. E IS COMPUTED FROM 2**(-E)=B**(1-I1MACH(14))=
   236  C     TOL WHERE B IS THE BASE OF THE ARITHMETIC.
   237  C-----------------------------------------------------------------------
   238        T1 = DBLE(FLOAT(I1MACH(14)-1))
   239        T1 = T1*D1MACH(5)*3.321928094D0
   240        T1 = DMAX1(T1,12.0D0)
   241        T1 = DMIN1(T1,60.0D0)
   242        T2 = TTH*T1 - 6.0D0
   243        IF (ZR.NE.0.0D0) GO TO 130
   244        T1 = HPI
   245        GO TO 140
   246    130 CONTINUE
   247        T1 = DATAN(ZI/ZR)
   248        T1 = DABS(T1)
   249    140 CONTINUE
   250        IF (T2.GT.CAZ) GO TO 170
   251  C-----------------------------------------------------------------------
   252  C     FORWARD RECURRENCE LOOP WHEN CABS(Z).GE.R2
   253  C-----------------------------------------------------------------------
   254        ETEST = AK/(DPI*CAZ*TOL)
   255        FK = CONER
   256        IF (ETEST.LT.CONER) GO TO 180
   257        FKS = CTWOR
   258        CKR = CAZ + CAZ + CTWOR
   259        P1R = CZEROR
   260        P2R = CONER
   261        DO 150 I=1,KMAX
   262          AK = FHS/FKS
   263          CBR = CKR/(FK+CONER)
   264          PTR = P2R
   265          P2R = CBR*P2R - P1R*AK
   266          P1R = PTR
   267          CKR = CKR + CTWOR
   268          FKS = FKS + FK + FK + CTWOR
   269          FHS = FHS + FK + FK
   270          FK = FK + CONER
   271          STR = DABS(P2R)*FK
   272          IF (ETEST.LT.STR) GO TO 160
   273    150 CONTINUE
   274        GO TO 310
   275    160 CONTINUE
   276        FK = FK + SPI*T1*DSQRT(T2/CAZ)
   277        FHS = DABS(0.25D0-DNU2)
   278        GO TO 180
   279    170 CONTINUE
   280  C-----------------------------------------------------------------------
   281  C     COMPUTE BACKWARD INDEX K FOR CABS(Z).LT.R2
   282  C-----------------------------------------------------------------------
   283        A2 = DSQRT(CAZ)
   284        AK = FPI*AK/(TOL*DSQRT(A2))
   285        AA = 3.0D0*T1/(1.0D0+CAZ)
   286        BB = 14.7D0*T1/(28.0D0+CAZ)
   287        AK = (DLOG(AK)+CAZ*DCOS(AA)/(1.0D0+0.008D0*CAZ))/DCOS(BB)
   288        FK = 0.12125D0*AK*AK/CAZ + 1.5D0
   289    180 CONTINUE
   290  C-----------------------------------------------------------------------
   291  C     BACKWARD RECURRENCE LOOP FOR MILLER ALGORITHM
   292  C-----------------------------------------------------------------------
   293        K = INT(SNGL(FK))
   294        FK = DBLE(FLOAT(K))
   295        FKS = FK*FK
   296        P1R = CZEROR
   297        P1I = CZEROI
   298        P2R = TOL
   299        P2I = CZEROI
   300        CSR = P2R
   301        CSI = P2I
   302        DO 190 I=1,K
   303          A1 = FKS - FK
   304          AK = (FKS+FK)/(A1+FHS)
   305          RAK = 2.0D0/(FK+CONER)
   306          CBR = (FK+ZR)*RAK
   307          CBI = ZI*RAK
   308          PTR = P2R
   309          PTI = P2I
   310          P2R = (PTR*CBR-PTI*CBI-P1R)*AK
   311          P2I = (PTI*CBR+PTR*CBI-P1I)*AK
   312          P1R = PTR
   313          P1I = PTI
   314          CSR = CSR + P2R
   315          CSI = CSI + P2I
   316          FKS = A1 - FK + CONER
   317          FK = FK - CONER
   318    190 CONTINUE
   319  C-----------------------------------------------------------------------
   320  C     COMPUTE (P2/CS)=(P2/CABS(CS))*(CONJG(CS)/CABS(CS)) FOR BETTER
   321  C     SCALING
   322  C-----------------------------------------------------------------------
   323        TM = ZABS(CMPLX(CSR,CSI,kind=KIND(1.0D0)))
   324        PTR = 1.0D0/TM
   325        S1R = P2R*PTR
   326        S1I = P2I*PTR
   327        CSR = CSR*PTR
   328        CSI = -CSI*PTR
   329        CALL ZMLT(COEFR, COEFI, S1R, S1I, STR, STI)
   330        CALL ZMLT(STR, STI, CSR, CSI, S1R, S1I)
   331        IF (INU.GT.0 .OR. N.GT.1) GO TO 200
   332        ZDR = ZR
   333        ZDI = ZI
   334        IF(IFLAG.EQ.1) GO TO 270
   335        GO TO 240
   336    200 CONTINUE
   337  C-----------------------------------------------------------------------
   338  C     COMPUTE P1/P2=(P1/CABS(P2)*CONJG(P2)/CABS(P2) FOR SCALING
   339  C-----------------------------------------------------------------------
   340        TM = ZABS(CMPLX(P2R,P2I,kind=KIND(1.0D0)))
   341        PTR = 1.0D0/TM
   342        P1R = P1R*PTR
   343        P1I = P1I*PTR
   344        P2R = P2R*PTR
   345        P2I = -P2I*PTR
   346        CALL ZMLT(P1R, P1I, P2R, P2I, PTR, PTI)
   347        STR = DNU + 0.5D0 - PTR
   348        STI = -PTI
   349        CALL ZDIV(STR, STI, ZR, ZI, STR, STI)
   350        STR = STR + 1.0D0
   351        CALL ZMLT(STR, STI, S1R, S1I, S2R, S2I)
   352  C-----------------------------------------------------------------------
   353  C     FORWARD RECURSION ON THE THREE TERM RECURSION WITH RELATION WITH
   354  C     SCALING NEAR EXPONENT EXTREMES ON KFLAG=1 OR KFLAG=3
   355  C-----------------------------------------------------------------------
   356    210 CONTINUE
   357        STR = DNU + 1.0D0
   358        CKR = STR*RZR
   359        CKI = STR*RZI
   360        IF (N.EQ.1) INU = INU - 1
   361        IF (INU.GT.0) GO TO 220
   362        IF (N.GT.1) GO TO 215
   363        S1R = S2R
   364        S1I = S2I
   365    215 CONTINUE
   366        ZDR = ZR
   367        ZDI = ZI
   368        IF(IFLAG.EQ.1) GO TO 270
   369        GO TO 240
   370    220 CONTINUE
   371        INUB = 1
   372        IF(IFLAG.EQ.1) GO TO 261
   373    225 CONTINUE
   374        P1R = CSRR(KFLAG)
   375        ASCLE = BRY(KFLAG)
   376        DO 230 I=INUB,INU
   377          STR = S2R
   378          STI = S2I
   379          S2R = CKR*STR - CKI*STI + S1R
   380          S2I = CKR*STI + CKI*STR + S1I
   381          S1R = STR
   382          S1I = STI
   383          CKR = CKR + RZR
   384          CKI = CKI + RZI
   385          IF (KFLAG.GE.3) GO TO 230
   386          P2R = S2R*P1R
   387          P2I = S2I*P1R
   388          STR = DABS(P2R)
   389          STI = DABS(P2I)
   390          P2M = DMAX1(STR,STI)
   391          IF (P2M.LE.ASCLE) GO TO 230
   392          KFLAG = KFLAG + 1
   393          ASCLE = BRY(KFLAG)
   394          S1R = S1R*P1R
   395          S1I = S1I*P1R
   396          S2R = P2R
   397          S2I = P2I
   398          STR = CSSR(KFLAG)
   399          S1R = S1R*STR
   400          S1I = S1I*STR
   401          S2R = S2R*STR
   402          S2I = S2I*STR
   403          P1R = CSRR(KFLAG)
   404    230 CONTINUE
   405        IF (N.NE.1) GO TO 240
   406        S1R = S2R
   407        S1I = S2I
   408    240 CONTINUE
   409        STR = CSRR(KFLAG)
   410        YR(1) = S1R*STR
   411        YI(1) = S1I*STR
   412        IF (N.EQ.1) RETURN
   413        YR(2) = S2R*STR
   414        YI(2) = S2I*STR
   415        IF (N.EQ.2) RETURN
   416        KK = 2
   417    250 CONTINUE
   418        KK = KK + 1
   419        IF (KK.GT.N) RETURN
   420        P1R = CSRR(KFLAG)
   421        ASCLE = BRY(KFLAG)
   422        DO 260 I=KK,N
   423          P2R = S2R
   424          P2I = S2I
   425          S2R = CKR*P2R - CKI*P2I + S1R
   426          S2I = CKI*P2R + CKR*P2I + S1I
   427          S1R = P2R
   428          S1I = P2I
   429          CKR = CKR + RZR
   430          CKI = CKI + RZI
   431          P2R = S2R*P1R
   432          P2I = S2I*P1R
   433          YR(I) = P2R
   434          YI(I) = P2I
   435          IF (KFLAG.GE.3) GO TO 260
   436          STR = DABS(P2R)
   437          STI = DABS(P2I)
   438          P2M = DMAX1(STR,STI)
   439          IF (P2M.LE.ASCLE) GO TO 260
   440          KFLAG = KFLAG + 1
   441          ASCLE = BRY(KFLAG)
   442          S1R = S1R*P1R
   443          S1I = S1I*P1R
   444          S2R = P2R
   445          S2I = P2I
   446          STR = CSSR(KFLAG)
   447          S1R = S1R*STR
   448          S1I = S1I*STR
   449          S2R = S2R*STR
   450          S2I = S2I*STR
   451          P1R = CSRR(KFLAG)
   452    260 CONTINUE
   453        RETURN
   454  C-----------------------------------------------------------------------
   455  C     IFLAG=1 CASES, FORWARD RECURRENCE ON SCALED VALUES ON UNDERFLOW
   456  C-----------------------------------------------------------------------
   457    261 CONTINUE
   458        HELIM = 0.5D0*ELIM
   459        ELM = DEXP(-ELIM)
   460        CELMR = ELM
   461        ASCLE = BRY(1)
   462        ZDR = ZR
   463        ZDI = ZI
   464        IC = -1
   465        J = 2
   466        DO 262 I=1,INU
   467          STR = S2R
   468          STI = S2I
   469          S2R = STR*CKR-STI*CKI+S1R
   470          S2I = STI*CKR+STR*CKI+S1I
   471          S1R = STR
   472          S1I = STI
   473          CKR = CKR+RZR
   474          CKI = CKI+RZI
   475          AS = ZABS(CMPLX(S2R,S2I,kind=KIND(1.0D0)))
   476          ALAS = DLOG(AS)
   477          P2R = -ZDR+ALAS
   478          IF(P2R.LT.(-ELIM)) GO TO 263
   479          CALL ZLOG(S2R,S2I,STR,STI,IDUM)
   480          P2R = -ZDR+STR
   481          P2I = -ZDI+STI
   482          P2M = DEXP(P2R)/TOL
   483          P1R = P2M*DCOS(P2I)
   484          P1I = P2M*DSIN(P2I)
   485          CALL ZUCHK(P1R,P1I,NW,ASCLE,TOL)
   486          IF(NW.NE.0) GO TO 263
   487          J = 3 - J
   488          CYR(J) = P1R
   489          CYI(J) = P1I
   490          IF(IC.EQ.(I-1)) GO TO 264
   491          IC = I
   492          GO TO 262
   493    263   CONTINUE
   494          IF(ALAS.LT.HELIM) GO TO 262
   495          ZDR = ZDR-ELIM
   496          S1R = S1R*CELMR
   497          S1I = S1I*CELMR
   498          S2R = S2R*CELMR
   499          S2I = S2I*CELMR
   500    262 CONTINUE
   501        IF(N.NE.1) GO TO 270
   502        S1R = S2R
   503        S1I = S2I
   504        GO TO 270
   505    264 CONTINUE
   506        KFLAG = 1
   507        INUB = I+1
   508        S2R = CYR(J)
   509        S2I = CYI(J)
   510        J = 3 - J
   511        S1R = CYR(J)
   512        S1I = CYI(J)
   513        IF(INUB.LE.INU) GO TO 225
   514        IF(N.NE.1) GO TO 240
   515        S1R = S2R
   516        S1I = S2I
   517        GO TO 240
   518    270 CONTINUE
   519        YR(1) = S1R
   520        YI(1) = S1I
   521        IF(N.EQ.1) GO TO 280
   522        YR(2) = S2R
   523        YI(2) = S2I
   524    280 CONTINUE
   525        ASCLE = BRY(1)
   526        CALL ZKSCL(ZDR,ZDI,FNU,N,YR,YI,NZ,RZR,RZI,ASCLE,TOL,ELIM)
   527        INU = N - NZ
   528        IF (INU.LE.0) RETURN
   529        KK = NZ + 1
   530        S1R = YR(KK)
   531        S1I = YI(KK)
   532        YR(KK) = S1R*CSRR(1)
   533        YI(KK) = S1I*CSRR(1)
   534        IF (INU.EQ.1) RETURN
   535        KK = NZ + 2
   536        S2R = YR(KK)
   537        S2I = YI(KK)
   538        YR(KK) = S2R*CSRR(1)
   539        YI(KK) = S2I*CSRR(1)
   540        IF (INU.EQ.2) RETURN
   541        T2 = FNU + DBLE(FLOAT(KK-1))
   542        CKR = T2*RZR
   543        CKI = T2*RZI
   544        KFLAG = 1
   545        GO TO 250
   546    290 CONTINUE
   547  C-----------------------------------------------------------------------
   548  C     SCALE BY DEXP(Z), IFLAG = 1 CASES
   549  C-----------------------------------------------------------------------
   550        KODED = 2
   551        IFLAG = 1
   552        KFLAG = 2
   553        GO TO 120
   554  C-----------------------------------------------------------------------
   555  C     FNU=HALF ODD INTEGER CASE, DNU=-0.5
   556  C-----------------------------------------------------------------------
   557    300 CONTINUE
   558        S1R = COEFR
   559        S1I = COEFI
   560        S2R = COEFR
   561        S2I = COEFI
   562        GO TO 210
   563  C
   564  C
   565    310 CONTINUE
   566        NZ=-2
   567        RETURN
   568        END