 
      FUNCTION SPENC(X)
C***BEGIN PROLOGUE  SPENC
C***DATE WRITTEN   780201   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  C5
C***KEYWORDS  SPECIAL FUNCTION,SPENCE-S
C***AUTHOR  FULLERTON, W., (LANL)
C***PURPOSE  Compute Spence's function.
C***DESCRIPTION
C
C Evaluate a form of Spence's function defined by
C        integral from 0 to X of  -ALOG(1-Y)/Y  DY.
C For ABS(X) .LE. 1, the uniformly convergent expansion
C        SPENC = sum K=1,infinity  X**K / K**2     is valid.
C
C Spence's function can be used to evaluate much more general integral
C forms.  For example,
C        integral from 0 to Z of  ALOG(A*X+B)/(C*X+D)  DX  =
C             ALOG(ABS(B-A*D/C))*ALOG(ABS(A*(C*X+D)/(A*D-B*C)))/C
C             - SPENC (A*(C*Z+D)/(A*D-B*C)) / C.
C
C Ref -- K. Mitchell, Philosophical Magazine, 40, p. 351 (1949).
C        Stegun and Abromowitz, AMS 55, p. 1004.
C
C
C Series for SPEN       on the interval  0.          to  5.00000D-01
C                                        with weighted error   6.82E-17
C                                         log weighted error  16.17
C                               significant figures required  15.22
C                                    decimal places required  16.81
C***REFERENCES  (NONE)
C***ROUTINES CALLED  CSEVL,INITS,R1MACH
C***END PROLOGUE  SPENC
