amos/zbinu.f

   1       SUBROUTINE ZBINU(ZR, ZI, FNU, KODE, N, CYR, CYI, NZ, RL, FNUL,
   2      * TOL, ELIM, ALIM)
   3 C***BEGIN PROLOGUE  ZBINU
   4 C***REFER TO  ZBESH,ZBESI,ZBESJ,ZBESK,ZAIRY,ZBIRY
   5 C
   6 C     ZBINU COMPUTES THE I FUNCTION IN THE RIGHT HALF Z PLANE
   7 C
   8 C***ROUTINES CALLED  AZABS,ZASYI,ZBUNI,ZMLRI,ZSERI,ZUOIK,ZWRSK
   9 C***END PROLOGUE  ZBINU
  10       DOUBLE PRECISION ALIM, AZ, CWI, CWR, CYI, CYR, DFNU, ELIM, FNU,
  11      * FNUL, RL, TOL, ZEROI, ZEROR, ZI, ZR, AZABS
  12       INTEGER I, INW, KODE, N, NLAST, NN, NUI, NW, NZ
  13       DIMENSION CYR(N), CYI(N), CWR(2), CWI(2)
  14       DATA ZEROR,ZEROI / 0.0D0, 0.0D0 /
  15 C
  16       NZ = 0
  17       AZ = AZABS(ZR,ZI)
  18       NN = N
  19       DFNU = FNU + DBLE(FLOAT(N-1))
  20       IF (AZ.LE.2.0D0) GO TO 10
  21       IF (AZ*AZ*0.25D0.GT.DFNU+1.0D0) GO TO 20
  22    10 CONTINUE
  23 C-----------------------------------------------------------------------
  24 C     POWER SERIES
  25 C-----------------------------------------------------------------------
  26       CALL ZSERI(ZR, ZI, FNU, KODE, NN, CYR, CYI, NW, TOL, ELIM, ALIM)
  27       INW = IABS(NW)
  28       NZ = NZ + INW
  29       NN = NN - INW
  30       IF (NN.EQ.0) RETURN
  31       IF (NW.GE.0) GO TO 120
  32       DFNU = FNU + DBLE(FLOAT(NN-1))
  33    20 CONTINUE
  34       IF (AZ.LT.RL) GO TO 40
  35       IF (DFNU.LE.1.0D0) GO TO 30
  36       IF (AZ+AZ.LT.DFNU*DFNU) GO TO 50
  37 C-----------------------------------------------------------------------
  38 C     ASYMPTOTIC EXPANSION FOR LARGE Z
  39 C-----------------------------------------------------------------------
  40    30 CONTINUE
  41       CALL ZASYI(ZR, ZI, FNU, KODE, NN, CYR, CYI, NW, RL, TOL, ELIM,
  42      * ALIM)
  43       IF (NW.LT.0) GO TO 130
  44       GO TO 120
  45    40 CONTINUE
  46       IF (DFNU.LE.1.0D0) GO TO 70
  47    50 CONTINUE
  48 C-----------------------------------------------------------------------
  49 C     OVERFLOW AND UNDERFLOW TEST ON I SEQUENCE FOR MILLER ALGORITHM
  50 C-----------------------------------------------------------------------
  51       CALL ZUOIK(ZR, ZI, FNU, KODE, 1, NN, CYR, CYI, NW, TOL, ELIM,
  52      * ALIM)
  53       IF (NW.LT.0) GO TO 130
  54       NZ = NZ + NW
  55       NN = NN - NW
  56       IF (NN.EQ.0) RETURN
  57       DFNU = FNU+DBLE(FLOAT(NN-1))
  58       IF (DFNU.GT.FNUL) GO TO 110
  59       IF (AZ.GT.FNUL) GO TO 110
  60    60 CONTINUE
  61       IF (AZ.GT.RL) GO TO 80
  62    70 CONTINUE
  63 C-----------------------------------------------------------------------
  64 C     MILLER ALGORITHM NORMALIZED BY THE SERIES
  65 C-----------------------------------------------------------------------
  66       CALL ZMLRI(ZR, ZI, FNU, KODE, NN, CYR, CYI, NW, TOL)
  67       IF(NW.LT.0) GO TO 130
  68       GO TO 120
  69    80 CONTINUE
  70 C-----------------------------------------------------------------------
  71 C     MILLER ALGORITHM NORMALIZED BY THE WRONSKIAN
  72 C-----------------------------------------------------------------------
  73 C-----------------------------------------------------------------------
  74 C     OVERFLOW TEST ON K FUNCTIONS USED IN WRONSKIAN
  75 C-----------------------------------------------------------------------
  76       CALL ZUOIK(ZR, ZI, FNU, KODE, 2, 2, CWR, CWI, NW, TOL, ELIM,
  77      * ALIM)
  78       IF (NW.GE.0) GO TO 100
  79       NZ = NN
  80       DO 90 I=1,NN
  81         CYR(I) = ZEROR
  82         CYI(I) = ZEROI
  83    90 CONTINUE
  84       RETURN
  85   100 CONTINUE
  86       IF (NW.GT.0) GO TO 130
  87       CALL ZWRSK(ZR, ZI, FNU, KODE, NN, CYR, CYI, NW, CWR, CWI, TOL,
  88      * ELIM, ALIM)
  89       IF (NW.LT.0) GO TO 130
  90       GO TO 120
  91   110 CONTINUE
  92 C-----------------------------------------------------------------------
  93 C     INCREMENT FNU+NN-1 UP TO FNUL, COMPUTE AND RECUR BACKWARD
  94 C-----------------------------------------------------------------------
  95       NUI = INT(SNGL(FNUL-DFNU)) + 1
  96       NUI = MAX0(NUI,0)
  97       CALL ZBUNI(ZR, ZI, FNU, KODE, NN, CYR, CYI, NW, NUI, NLAST, FNUL,
  98      * TOL, ELIM, ALIM)
  99       IF (NW.LT.0) GO TO 130
 100       NZ = NZ + NW
 101       IF (NLAST.EQ.0) GO TO 120
 102       NN = NLAST
 103       GO TO 60
 104   120 CONTINUE
 105       RETURN
 106   130 CONTINUE
 107       NZ = -1
 108       IF(NW.EQ.(-2)) NZ=-2
 109       RETURN
 110       END