Mercurial > octave
view liboctave/external/amos/cwrsk.f @ 23434:f4d4d83f15c5
maint: rename cruft/ directory to external/
* liboctave/external: Renamed from liboctave/cruft.
*
* configure.ac: Rename XTRA_CRUFT_SH_LDFLAGS to XTRA_EXTERNAL_SH_LDFLAGS.
Rename CRUFT_DLL_DEFS to EXTERNAL_DLL_DEFS.
* install.txi: Update documentation to refer to liboctave/external.
* HACKING: Update explanation of directory tree.
* liboctave/module.mk: Update build system to include liboctave/external
* liboctave/numeric/module.mk: Update CPPFLAGS to find Faddeeva in external/
directory.
* lo-blas-proto.h, lo-lapack-proto.h: Update comments which referred to cruft
directory.
author | Rik <rik@octave.org> |
---|---|
date | Mon, 24 Apr 2017 21:03:38 -0700 |
parents | liboctave/cruft/amos/cwrsk.f@648dabbb4c6b |
children |
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SUBROUTINE CWRSK(ZR, FNU, KODE, N, Y, NZ, CW, TOL, ELIM, ALIM) C***BEGIN PROLOGUE CWRSK C***REFER TO CBESI,CBESK C C CWRSK COMPUTES THE I BESSEL FUNCTION FOR RE(Z).GE.0.0 BY C NORMALIZING THE I FUNCTION RATIOS FROM CRATI BY THE WRONSKIAN C C***ROUTINES CALLED CBKNU,CRATI,R1MACH C***END PROLOGUE CWRSK COMPLEX CINU, CSCL, CT, CW, C1, C2, RCT, ST, Y, ZR REAL ACT, ACW, ALIM, ASCLE, ELIM, FNU, S1, S2, TOL, YY INTEGER I, KODE, N, NW, NZ DIMENSION Y(N), CW(2) C----------------------------------------------------------------------- C I(FNU+I-1,Z) BY BACKWARD RECURRENCE FOR RATIOS C Y(I)=I(FNU+I,Z)/I(FNU+I-1,Z) FROM CRATI NORMALIZED BY THE C WRONSKIAN WITH K(FNU,Z) AND K(FNU+1,Z) FROM CBKNU. C----------------------------------------------------------------------- NZ = 0 CALL CBKNU(ZR, FNU, KODE, 2, CW, NW, TOL, ELIM, ALIM) IF (NW.NE.0) GO TO 50 CALL CRATI(ZR, FNU, N, Y, TOL) C----------------------------------------------------------------------- C RECUR FORWARD ON I(FNU+1,Z) = R(FNU,Z)*I(FNU,Z), C R(FNU+J-1,Z)=Y(J), J=1,...,N C----------------------------------------------------------------------- CINU = CMPLX(1.0E0,0.0E0) IF (KODE.EQ.1) GO TO 10 YY = AIMAG(ZR) S1 = COS(YY) S2 = SIN(YY) CINU = CMPLX(S1,S2) 10 CONTINUE C----------------------------------------------------------------------- C ON LOW EXPONENT MACHINES THE K FUNCTIONS CAN BE CLOSE TO BOTH C THE UNDER AND OVERFLOW LIMITS AND THE NORMALIZATION MUST BE C SCALED TO PREVENT OVER OR UNDERFLOW. CUOIK HAS DETERMINED THAT C THE RESULT IS ON SCALE. C----------------------------------------------------------------------- ACW = CABS(CW(2)) ASCLE = 1.0E+3*R1MACH(1)/TOL CSCL = CMPLX(1.0E0,0.0E0) IF (ACW.GT.ASCLE) GO TO 20 CSCL = CMPLX(1.0E0/TOL,0.0E0) GO TO 30 20 CONTINUE ASCLE = 1.0E0/ASCLE IF (ACW.LT.ASCLE) GO TO 30 CSCL = CMPLX(TOL,0.0E0) 30 CONTINUE C1 = CW(1)*CSCL C2 = CW(2)*CSCL ST = Y(1) C----------------------------------------------------------------------- C CINU=CINU*(CONJG(CT)/CABS(CT))*(1.0E0/CABS(CT) PREVENTS C UNDER- OR OVERFLOW PREMATURELY BY SQUARING CABS(CT) C----------------------------------------------------------------------- CT = ZR*(C2+ST*C1) ACT = CABS(CT) RCT = CMPLX(1.0E0/ACT,0.0E0) CT = CONJG(CT)*RCT CINU = CINU*RCT*CT Y(1) = CINU*CSCL IF (N.EQ.1) RETURN DO 40 I=2,N CINU = ST*CINU ST = Y(I) Y(I) = CINU*CSCL 40 CONTINUE RETURN 50 CONTINUE NZ = -1 IF(NW.EQ.(-2)) NZ=-2 RETURN END