Closure in RPL

[Thomas Klemm]

I was goofing around with a filter I could use with DOSUBS to remove all multiples of a number n.
So I tried to write a program that creates it based on that number as input.

Since that didn't work, I moved this part into a program that does it:

Code:

\<< \-> p n
  \<< p
    \<< \-> k
      \<<
        IF k n == k n MOD OR
        THEN k
        END
      \>>
    \>> DOSUBS
  \>>
\>>

Let's say we call this program SIEVE.
Then we start with a list of numbers:

K ENTER
ENTER
2 887 1 SEQ

{ 2 3 4 5 6 7 8 9 10 … 887 }

Now we can remove all multiples of primes with:

2 SIEVE
{ 2 3 5 7 9 11 13 15 17 … 887 }

3 SIEVE
{ 2 3 5 7 11 13 17 19 23 … 887 }

5 SIEVE
{ 2 3 5 7 11 13 17 19 23 … 887 }

Just continue with the next prime in the list.
…
We can stop at \(31\) since \(31^2 > 887\).

31 SIEVE
{ 2 3 5 7 11 13 17 19 23 … 887 }

This list of primes can then be reversed and transformed into an array:

[ 887 883 881 877 … 7 5 3 2 ]

It is the input for the following program:

Code:

\<< PROOT OBJ\-> OBJ\-> DROP \->LIST
  ABS
  :: MIN DTAG STREAM
\>>

.806513599261

---

Thanks for your reply and your suggestions.
As you can see I could still solve the problem.
I was just wondering if maybe I missed an obvious solution.