(25C) Sampling without repetition

[Thomas Klemm]

Here's a translation of your program for the HP-42S:

Code:

00 { 41-Byte Prgm }
01▸LBL "SAMPLE"
02 RCL 00
03 STO 02
04 RCL 01
05 STO 03
06▸LBL 00
07 RCL 03
08 RCL 02
09 ÷
10 RAN
11 X≥Y?
12 GTO 01
13 RCL 02
14 STOP
15 DSE 03
16 GTO 01
17 GTO 02
18▸LBL 01
19 DSE 02
20 GTO 00
21▸LBL 02
22 -1
23 END

However, I reversed the order so I could use DSE.
Thus the generated samples appear in descending order.

Example:

100
STO 00
10
STO 01
XEQ "SAMPLE"
85
R/S
64
R/S
62
R/S
59
R/S
55
R/S
53
R/S
39
R/S
32
R/S
30
R/S
11
R/S
-1

(04-27-2017 04:07 AM)nsg Wrote:  I wonder if it is possible to improve on the algorithm and generate a sample of modest k for arbitrary N, for example, a sample of 30 out of 10000000.

In this case we might simply generate them at random and hope there's no collision.

Kind regards
Thomas