mini-challenge from UH contest
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From: Virgil on 2 Dec 2009 02:07 In article <0dde68ee-7733-4500-9b55-34098bb88f5d(a)g12g2000yqa.googlegroups.com>, Yann <kdo4973(a)gmail.com> wrote: > Virgil's version with trivial speed-oriented modifications : > down to 25.69 sec (90.5 bytes, #D361h) > > \<< > 1 DUPDUP 4 ROLL > START > NEXTPRIME SWAP OVER * SWAP > NEXT > 0 SWAP NEXTPRIME 4 ROLL > FOR X > X PICK3 GCD 1 == + > 2 STEP NIP > \>> I cannot get the above to work at all. Are you sure that you didn't mean \<< 1 DUPDUP 4 ROLL START NEXTPRIME SWAP OVER * SWAP NEXT DROP 0 1 4 ROLL FOR X X PICK3 GCD 1 == + 2 STEP NIP \>> in which the only change is to replace my "NEXT" with "2 STEP"?
From: Wes on 2 Dec 2009 12:50 On Dec 2, 10:07 am, Virgil <Vir...(a)home.esc> wrote: > I cannot get the above to work at all. > 0 SWAP NEXTPRIME 4 ROLL Perhaps he meant 1 SWAP NEXTPRIME 4 ROLL Besides "2 NEXT", here are a couple of more small tweaks: If you don't mind using LASTARG, you can save a 2.5 byte instruction if you replace NEXTPRIME SWAP OVER * SWAP with NEXTPRIME * LASTARG NIP and if you don't mind putting the 2.5 bytes back, 1 DUPDUP 4 ROLL can be replace with 1 2 DUP 4 ROLL for a tiny speedup. This leaves 2 out of your product, but if you're using "2 STEP" then you're not checking even numbers anyway, and I figure GCD might be slightly faster with a smaller value. Here's a summary of what I think are the best combinations of code. Hats off to Virgil for his clever algorithm. @ best size*runtime: 85 bytes, 30.0192 seconds = 2.49 KB*sec \<< 1 DUPDUP 4 ROLL START NEXTPRIME * LASTARG NIP NEXT DROP 0 1 4 ROLL FOR X X PICK3 GCD 1 == + 2 STEP NIP \>> @ fastest: 90.5 bytes, 29.8118 seconds = 2.63 KB*sec \<< 1 2 DUP 4 ROLL START NEXTPRIME * LASTARG NIP NEXT 1 SWAP NEXTPRIME 4 ROLL FOR X X PICK3 GCD 1 == + 2 STEP NIP \>> @ smallest: 79.5 bytes, 187.9637 sec = 14.59 KB*sec \<< 2. 2. PICK3 START SWAP OVER NEXTPRIME NEXT SWAP \->LIST 0. 1. 4. ROLL FOR I I PICK3 MOD 0. POS NOT + NEXT NIP \>> -wes
From: Wes on 3 Dec 2009 10:46
On Dec 2, 8:50 pm, Wes <wjltemp...(a)yahoo.com> wrote: > @ best size*runtime: 85 bytes, 30.0192 seconds = 2.49 KB*sec > @ fastest: 90.5 bytes, 29.8118 seconds = 2.63 KB*sec > @ smallest: 79.5 bytes, 187.9637 sec = 14.59 KB*sec Hang on, I see another improvement on two of these. Use Virgil's GCD idea, but instead of using a FOR loop in the 2nd half of the program, use SEQ and process the list. For really large values, this list might take up a lot of memory, but it seems to run pretty well with the test values. @ best size*runtime: 82.5 bytes(#929Eh), 28.1229 seconds = 2.27 KB*sec \<< 1 DUPDUP 4 ROLL START NEXTPRIME * LASTARG NIP NEXT DROP RCLVX DUP 1 5 ROLL 2 SEQ GCD 1 - NOT \GSLIST \>> @ fastest: 93 bytes(#18B7h), 27.7733 seconds = 2.52 KB*sec \<< 1 2 DUP 4 ROLL START NEXTPRIME * LASTARG NIP NEXT NEXTPRIME RCLVX DUP ROT 5 ROLL 2 SEQ GCD 1 - NOT \GSLIST 1 + \>> -wes |