src/numerical/slatec/fortran/dqwgts.f

   1 *DECK DQWGTS
   2       DOUBLE PRECISION FUNCTION DQWGTS (X, A, B, ALFA, BETA, INTEGR)
   3 C***BEGIN PROLOGUE  DQWGTS
   4 C***SUBSIDIARY
   5 C***PURPOSE  This function subprogram is used together with the
   6 C            routine DQAWS and defines the WEIGHT function.
   7 C***LIBRARY   SLATEC
   8 C***TYPE      DOUBLE PRECISION (QWGTS-S, DQWGTS-D)
   9 C***KEYWORDS  ALGEBRAICO-LOGARITHMIC, END POINT SINGULARITIES,
  10 C             WEIGHT FUNCTION
  11 C***AUTHOR  Piessens, Robert
  12 C             Applied Mathematics and Programming Division
  13 C             K. U. Leuven
  14 C           de Doncker, Elise
  15 C             Applied Mathematics and Programming Division
  16 C             K. U. Leuven
  17 C***SEE ALSO  DQK15W
  18 C***ROUTINES CALLED  (NONE)
  19 C***REVISION HISTORY  (YYMMDD)
  20 C   810101  DATE WRITTEN
  21 C   890531  Changed all specific intrinsics to generic.  (WRB)
  22 C   890531  REVISION DATE from Version 3.2
  23 C   891214  Prologue converted to Version 4.0 format.  (BAB)
  24 C   900328  Added TYPE section.  (WRB)
  25 C***END PROLOGUE  DQWGTS
  26 C
  27       DOUBLE PRECISION A,ALFA,B,BETA,BMX,X,XMA
  28       INTEGER INTEGR
  29 C***FIRST EXECUTABLE STATEMENT  DQWGTS
  30       XMA = X-A
  31       BMX = B-X
  32       DQWGTS = XMA**ALFA*BMX**BETA
  33       GO TO (40,10,20,30),INTEGR
  34    10 DQWGTS = DQWGTS*LOG(XMA)
  35       GO TO 40
  36    20 DQWGTS = DQWGTS*LOG(BMX)
  37       GO TO 40
  38    30 DQWGTS = DQWGTS*LOG(XMA)*LOG(BMX)
  39    40 RETURN
  40       END