d3/dc3/dgamlm_8f_source.html

 *DECK DGAMLM

       SUBROUTINE dgamlm (XMIN, XMAX)

 C***BEGIN PROLOGUE  DGAMLM

 C***PURPOSE  Compute the minimum and maximum bounds for the argument in

 C            the Gamma function.

 C***LIBRARY   SLATEC (FNLIB)

 C***CATEGORY  C7A, R2

 C***TYPE      DOUBLE PRECISION (GAMLIM-S, DGAMLM-D)

 C***KEYWORDS  COMPLETE GAMMA FUNCTION, FNLIB, LIMITS, SPECIAL FUNCTIONS

 C***AUTHOR  Fullerton, W., (LANL)

 C***DESCRIPTION

 C

 C Calculate the minimum and maximum legal bounds for X in gamma(X).

 C XMIN and XMAX are not the only bounds, but they are the only non-

 C trivial ones to calculate.

 C

 C             Output Arguments --

 C XMIN   double precision minimum legal value of X in gamma(X).  Any

 C        smaller value of X might result in underflow.

 C XMAX   double precision maximum legal value of X in gamma(X).  Any

 C        larger value of X might cause overflow.

 C

 C***REFERENCES  (NONE)

 C***ROUTINES CALLED  D1MACH, XERMSG

 C***REVISION HISTORY  (YYMMDD)

 C   770601  DATE WRITTEN

 C   890531  Changed all specific intrinsics to generic.  (WRB)

 C   890531  REVISION DATE from Version 3.2

 C   891214  Prologue converted to Version 4.0 format.  (BAB)

 C   900315  CALLs to XERROR changed to CALLs to XERMSG.  (THJ)

 C***END PROLOGUE  DGAMLM

       DOUBLE PRECISION XMIN, XMAX, ALNBIG, ALNSML, XLN, XOLD, D1MACH

 C***FIRST EXECUTABLE STATEMENT  DGAMLM

       alnsml = log(d1mach(1))

       xmin = -alnsml

       DO 10 i=1,10

         xold = xmin

         xln = log(xmin)

         xmin = xmin - xmin*((xmin+0.5d0)*xln - xmin - 0.2258d0 + alnsml)

      1    / (xmin*xln+0.5d0)

         IF (abs(xmin-xold).LT.0.005d0) go to 20

  10   CONTINUE

       CALL xermsg('SLATEC', 'DGAMLM', 'UNABLE TO FIND XMIN', 1, 2)

 C

  20   xmin = -xmin + 0.01d0

 C

       alnbig = log(d1mach(2))

       xmax = alnbig

       DO 30 i=1,10

         xold = xmax

         xln = log(xmax)

         xmax = xmax - xmax*((xmax-0.5d0)*xln - xmax + 0.9189d0 - alnbig)

      1    / (xmax*xln-0.5d0)

         IF (abs(xmax-xold).LT.0.005d0) go to 40

  30   CONTINUE

       CALL xermsg('SLATEC', 'DGAMLM', 'UNABLE TO FIND XMAX', 2, 2)

 C

  40   xmax = xmax - 0.01d0

       xmin = max(xmin, -xmax+1.d0)

 C

       RETURN

       END

log
OCTAVE_EXPORT octave_value_list or N dimensional array whose elements are all equal to the base of natural logarithms The constant ex $e satisfies the equation log(e)

dgamlm
subroutine dgamlm(XMIN, XMAX)
Definition: dgamlm.f:2

to
may be zero for pure relative error test tem the relative tolerance must be greater than or equal to
Definition: Quad-opts.cc:233

max
charNDArray max(char d, const charNDArray &m)
Definition: chNDArray.cc:228

xermsg
subroutine xermsg(LIBRAR, SUBROU, MESSG, NERR, LEVEL)
Definition: xermsg.f:2

abs
OCTAVE_EXPORT octave_value_list return the value of the option it must match the dimension of the state and the relative tolerance must also be a vector of the same length tem it must match the dimension of the state and the absolute tolerance must also be a vector of the same length The local error test applied at each integration step is xample roup abs(local error in x(i))<