12-18-2013, 12:55 AM

Gamma Function using Spouge's method.

Memory Map

R00 = x and = x-1

R01 = a

R02 = CHS

R03 = Sum

R04 = I

R05 = sqrt(2*pi)

R06 = integer part of I

Implementation

Memory Map

R00 = x and = x-1

R01 = a

R02 = CHS

R03 = Sum

R04 = I

R05 = sqrt(2*pi)

R06 = integer part of I

Implementation

Code:

`1 LBL "GAMMA"`

2 LBL A

3 "X?"

4 PROMPT

5 1

6 -

7 STO 00

8 12.5

9 STO 01 # a = 12.5

10 1

11 STO 02 # CHS = 1

12 STO 03 # Sum = 1

13 2

14 PI

15 *

16 SQRT

17 STO 05 # sqrt(2*pi)

18 1.012

19 STO 04 # set up loop control variable

20 LBL 00 # start the loop

21 RCL 02

22 RCL 05

23 /

24 RCL 04

25 INT

26 STO 06

27 1

28 -

29 FACT

30 /

31 RCL 01

32 RCL 06

33 -

34 RCL 06

35 0.5

36 -

37 Y^X

38 *

39 RCL 01

40 RCL 07

41 -

42 EXP

43 *

44 RCL 06

45 RCL 00

46 +

47 /

48 STO+ 03 # Sum = Sum + C/(X+I)

49 RCL 02

50 CHS

51 STO 02 # CHS = -CHS

52 ISG 04 # end of loop

53 GTO 00

54 RCL 00

55 RCL 01

56 +

57 STO 06

58 RCL 00

59 0.5

60 +

61 Y^X

62 RCL 06

63 EXP

64 /

65 RCL 05

66 *

67 RCL 03

68 *

69 "GAMA="

70 ARCL X

71 PROMPT

72 GTO A