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Double factorial [wp34s]
02-12-2016, 12:03 AM
Post: #1
Double factorial [wp34s]
Code:

// Opcode map source: wp34s.op (local directory)
// Opcode SVN version: -- unknown --
// wp34s_asm.exe: Source file(s): wp34s.dat
0001 **LBL A
0002 ENTER[^]
0003 1
0004 +/-
0005 ACOS
0006 RCL[times] Y
0007 COS
0008 DEC X
0009 4
0010 /
0011 x[<->] Y
0012 2
0013 /
0014 RCL- Y
0015 RCL L
0016 x!
0017 x[<->] Y
0018 2[^x]
0019 [times]
0020 x[<->] Y
0021 # [pi]
0022 x[<->] Y
0023 y[^x]
0024 [times]
0025 RTN
0026 **LBL B
0027 RCL+ X
0028 DEC X
0029 DEC X
0030 STO+ Y
0031 x[<->] L
0032 XEQ C
0033 RTN
0034 **LBL C
0035 STO+ X
0036 RCL- Y
0037 +/-
0038 x[<->] Y
0039 XEQ 001
0040 x[<->] Y
0041 XEQ 001
0042 /
0043 RTN
0044 **LBL 001
0045 # 1/2
0046 x[<->] Y
0047 RCL[times] Y
0048 x!
0049 x[<->] Y
0050 RCL+ L
0051 2[^x]
0052 [times]
0053 # [pi]
0054 [sqrt]
0055 /
0056 RTN
0057 **LBL D
0058 ENTER[^]
0059 INC X
0060 # 002
0061 IDIV
0062 XEQ C
0063 RTN
0064 END
// 64 total instructions used.
// 64 total words used.
// 64 single word instructions.
// 0 double word instructions.

Program A: double factorial. This uses the formula used by Wolfram Alpha:

\[x!!=2^{\frac{x}{2}-\frac{\cos \left ( \pi x \right )-1}{4}}\times \pi ^{\frac{\cos \left ( \pi x \right )-1}{4}}\times\left ( \frac{x}{2} \right )!\]

4 A --> 8
6 A --> 48
7.77 A --> 290.3223156096666
8.88 +/- A --> 0.01106808239125682
3.33 +/- A --> -1,065802995433050
5 +/- A --> 0.3333333333333334

Program B: rising double factorial.

9.8 ENTER 3 B --> 1595.832000000000 ; 9.8 * 11.8 * 13.8 = 1595.832
8.1 ENTER 4 B --> 13957.60410000001 ; 8.1 * 10.1 * 12.1 * 14.1 = 13957.6041

Program C: falling double factorial.

7.7 ENTER 2 C --> 43.88999999999996 ; 7.7 * 5.7 = 43.89
6.6 ENTER 3 C --> 78.93600000000006 ; 6.6 * 4.6 * 2.6 = 78.936

Program D: double factorial (integer arguments). This and programs B and C uses a more simple formula found at Wikipedia.

5 +/- D --> 0.3333333333333334
3 +/- D --> -1
4 D --> 8.000000000000001
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Messages In This Thread
Double factorial [wp34s] - Gerson W. Barbosa - 02-12-2016 12:03 AM
RE: Double factorial [wp34s] - Paul Dale - 02-12-2016, 06:27 AM
RE: Double factorial [wp34s] - Dieter - 02-12-2016, 07:49 AM
RE: Double factorial [wp34s] - Dieter - 02-12-2016, 07:54 PM
RE: Double factorial [wp34s] - Paul Dale - 02-13-2016, 12:14 AM
RE: Double factorial [wp34s] - Paul Dale - 02-12-2016, 10:45 AM
RE: Double factorial [wp34s] - Paul Dale - 02-12-2016, 10:33 PM
RE: Double factorial [wp34s] - Paul Dale - 02-13-2016, 10:41 PM
RE: Double factorial [wp34s] - Dieter - 02-15-2016, 07:03 AM
RE: Double factorial [wp34s] - emece67 - 02-13-2016, 12:57 AM
RE: Double factorial [wp34s] - Paul Dale - 02-13-2016, 04:46 AM
RE: Double factorial [wp34s] - Dieter - 02-13-2016, 06:53 AM
RE: Double factorial [wp34s] - Paul Dale - 02-13-2016, 07:05 AM
RE: Double factorial [wp34s] - Dieter - 02-13-2016, 07:00 PM
RE: Double factorial [wp34s] - emece67 - 02-13-2016, 09:15 AM
RE: Double factorial [wp34s] - John Keith - 02-14-2016, 03:24 PM



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