TUgammaFn TCL UTILITIES USER MANUAL TUgammaFn
SYNOPSIS
Compute Γ(X) and ln(Γ(X))
PACKAGE
TCLUTILS
NAME
TUgammaFn
USAGE
set rV  [TUgammaFn  X FmT]
INPUT DEFINITIONS
X - Input to the gamma function. Must be > 0.0.
FmT - The format of the returned value
GAMMA : Return Γ(X)
LGAMMA : Return ln(Γ(X))
RETURN DEFINITION
rV - If X <= 0.0 the string BaD is returned. If X > 0.0 either Γ(X) or ln(Γ(X)) is returned depending on FmT.
DESCRIPTION
TUgammaFn computes either the gamma function or natural log of the gamma function of X depending on how FmT is set. X must be > 0.0 otherwise an error is returned in rV.
ERRORS
None Generated
C BACKING
No
EXAMPLE(S) 
# COMPUTE GAMMA and LN(GAMMA) FUNCTION

set A [TUgammaFn 0.50 GAMMA]
set B [TUgammaFn 0.50 LGAMMA]
set C [TUgammaFn 1.29 GAMMA]
set D [TUgammaFn 1.29 LGAMMA]
set E [TUgammaFn 6.70 GAMMA]
set F [TUgammaFn 6.70 LGAMMA]

# PRINT results

puts stderr "GAMMA(0.5)   : [format "%.5f" $A]"
puts stderr "LGAMMA(0.5)  : [format "%.5f" $B]"
puts stderr "GAMMA(1.29)  : [format "%.5f" $C]"
puts stderr "LGAMMA(1.29) : [format "%.5f" $D]"
puts stderr "GAMMA(6.7)   : [format "%.5f" $E]"
puts stderr "LGAMMA(6.7)  : [format "%.5f" $F]"


> GAMMA(0.5)   : 1.77245
> LGAMMA(0.5)  : 0.57236
> GAMMA(1.29)  : 0.89904
> LGAMMA(1.29) : -0.10643
> GAMMA(6.7)   : 413.40752
> LGAMMA(6.7)  : 6.02443
Sept 19, 2006