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HP-12C program


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Post: #7
02-21-2012, 05:43 PM
Gerson W. Barbosa Offline
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001-	1		016-	+

002-	0		017-	1/x

003-	x<>y		018-	STO 1

004-	y^x		019-	RCL 0

005-	STO 0		020-	3

006-	ENTER		021-	CHS

007-	*		022-	y^x

008-  g LSTx		023-	STO+ 1

009-	2		024-	1

010-	*		025-	STO- 0

011-	1		026-	RCL 0

012-	+		027-  g x=0

013-	x<>y		028-  g GTO 30

014-	2		029-  g GTO 19

015-	*		030-	RCL 1

                        031-  g GTO 00

Given the proper argument this small HP-12C program will give a meaningful result in about 2 minutes on the classic HP-12C (under a couple of seconds on the HP-12C+).

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Post: #8
02-21-2012, 06:07 PM
Paul Dale Offline
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Very nice!

Not having a 12C to hand, I converted this for the 34S:

    01:  LBL A

    02:  10[^x]

    03:  STO 00

    04:  x[^2]

    05:  RCL L

    06:  RCL+ X

    07:  INC X

    08:  x[<->] Y

    09:  RCL+ X

    10:  +

    11:  1/x

    12:  STO 01

    13:  LBL 00

    14:  RCL 00

    15:  3

    16:  +/-

    17:  y[^x]

    18:  STO+ 01

    19:  DSZ 00

    20:  GTO 00

    21:  RCL 01

    22:  RTN

However, there is an alternative WP 34S program that produces the same limit using four steps including the LBL at the start and the RTN at the end -- so two steps of working code.


- Pauli

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Post: #9
02-21-2012, 06:10 PM
Paul Dale Offline
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Drat, missed some optimisation in the above code. Change line 18 to + and delete lines 21 and 12.


- Pauli

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Post: #10
02-21-2012, 06:22 PM
Gerson W. Barbosa Offline
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I thought of including "optimization of the code is left as an exercise to the reader", but then I realized figuring out what the program did was good exercise enough. That was my first attempt after I noticed it this afternoon. Without the trick, about 50k terms would have to be computed in order to get the same result.

Gerson.

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Post: #11
02-21-2012, 06:12 PM
Gerson W. Barbosa Offline
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Quote:
However, there is an alternative WP 34S program that produces the same limit using four steps including the LBL at the start and the RTN at the end -- so two steps of working code.

Actually, I've tested my results upon the WP 34S function :-)

Gerson.

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Post: #12
02-22-2012, 04:12 AM
Gerson W. Barbosa Offline
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While we're at it, here's another one for another constant:

001-	1		019-	CHS	

002-	0		020-	STO+ 0	

003-	x<>y		021-	STO* 2	

004-	y^x		022-	RCL 0	

005-	STO 0		023-	2	

006-	ENTER		024-	*	

007-	*		025-	+	

008-	8		026-	ENTER	

009-	*		027-	*	

010-	6		028-	1/x	

011-	+		029-	RCL 2	

012-	1/x		030-	*	

013-	STO 1		031-	STO+ 1	

014-	1		032-	RCL 0	

015-	STO+ 0		033-	g x=0	

016-	STO+ 1		034-	g GTO 36	

017-	STO 2		035-	g GTO 18	

018-	1		036-	RCL 1	

			037-	g GTO 00

Checking the archives, I found an old mini-challenge of Valentin's which is worth mentioning. Crawl's program in Message #52 appears to explore the same idea. I certainly read the thread at the time, but I'd completely forgotten about his particular program. It's worth reading Valentin's original solutions and other therein:

http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv016.cgi?read=95861

I've come up with a slightly faster series. I've started to implement it on the HP-15C LE, but the initialization alone takes up 37 steps. If I manage to optimize it a bit, I'll present it later.

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