[34S] Time diff. STO.00 vs. STO 00 ?

03142014, 03:28 AM
Post: #21




RE: [34S] Time diff. STO.00 vs. STO 00 ?
(03132014 09:53 PM)Paul Dale Wrote:(03132014 09:20 PM)Sikuq Wrote: However I always wondered just how the 34S actually calculates say a square root or the Gamma function. Does it use a power series, other basic functions, or say Fourier? And did you get those functions from somewhere else and just compiled them in there? Pauli, Despite Walter's possible consternation I allow myself to requote you fully. Your post is so profoundly interesting to me and I am sure most other 34S users that it would be a shame to truncate it. I wish I had had the knowledge and involvement at that time to experience what I can only describe and imagine as a transcontinental total brainstorming which at times lead to Nobel Prizes. I can vividly imagine your discussions as to size, accuracy, speed, convergence, etc. I never did know that you guys were so involved at that fundamental level. My interest in this topic has boosted and I must look into your sources and elsewhere. Years ago I did my own simple NewtonRaphson and secant method solve routine on my HP41C and I remember it was sometimes calculating overnight before it printed out on my small HP thermal printer. I did have two of the HP 41C ILLoop tape drives but I can't remember if I involved those. I was solving some huge complicated Gamma functions. One of my problems was to discern which of the multiple solutions were legitimate. I still have problems with those issues; I can never make up my mind as I have often been unable to establish a delimiting criteria for solution detection. Thus I often worry about the consequences of the solution I let go of coming home to roost. I'm going to have a sleepless night thinking about your exciting endeavors.  Sikuq 

03142014, 05:37 AM
Post: #22




RE: [34S] Time diff. STO.00 vs. STO 00 ?
Dear Sikuq,
You're right guessing is another hobby of me. But now  since it looks like you're a lonely offspring of a (not as lonely!) medieval Viking monk on a lonely island I can only congratulate to your location: Enjoy and keep it! ((Just some reasoning: regards copying as a value per se increasing the value of the copied text (compare e.g. Umberto Eco's "The Name of the Rose"), long distance given in nmi to a university, chosen forum name (sounds a bit Inuktitut to me), lack of grammatical knowledge (contact to Latin lost for long), etc. )) Seriously, I didn't want to offend you  your questions just sound sometimes that a little bit of own research would ... ummh ... help. But times have changed and are changing  nowadays the intelligence is in the web ... d;) I'll try to resist to comment on your future posts but can't promise to succeed 

03142014, 07:18 AM
Post: #23




RE: [34S] Time diff. STO.00 vs. STO 00 ?
The majority of the discussions about the numerical accuracy are stored in the old forum archives. There was surprisingly little discussion about this elsewhere.
 Pauli 

03142014, 02:47 PM
(This post was last modified: 03142014 07:16 PM by Sikuq.)
Post: #24




RE: [34S] Time diff. STO.00 vs. STO 00 ?
Walter,
I am not one bit offended, au contraire! I am in fact honored by the discussions going on here. Please keep commenting. It does force me to do some new research and the feedback by Marcus, yourself, Pauli, Franz, and others are always very informative. Your WP34S team is such an unusual group of such high intellect that at times I feel like a fool. You are this time amazingly correct in you assumptions except for the lonely offspring part. I did go west like Vikings do and I did snatch a cute little local girl like Vikings do...  Sikuq Edit 1,2. Walter, f.y.i., Sikuq= ice in my Eskimo variant. You are very observant indeed. 

03142014, 05:01 PM
(This post was last modified: 03142014 05:04 PM by Sikuq.)
Post: #25




RE: [34S] Time diff. STO.00 vs. STO 00 ?
(03142014 07:18 AM)Paul Dale Wrote: The majority of the discussions about the numerical accuracy are stored in the old forum archives. There was surprisingly little discussion about this elsewhere. Pauli, The story behind your 34S is astounding; yes, it certainly has not been exposed to the extent I would have guessed. I woke up several times over night thinking of the 34S team running around in Australia and Germany seeking algorithm books, and also recalling my own attempts to make my own Newton routine faster. Sometimes I would simplegraph the function on the HP41C loop printer and count the roots. Does the user FIX setting in any way affect the actual step length used?  Sikuq PS: Pauli, is there any way you can test how many loops it takes to calculate the squareroot of say 1234567 on the 34S? Is the step length fixed or does it reduce itself closer to convergence (i.e. sign change)? And how did it calculate the initial guess? 

03142014, 05:34 PM
Post: #26




RE: [34S] Time diff. STO.00 vs. STO 00 ?
(03142014 05:01 PM)Sikuq Wrote: PS: Pauli, is there any way you can test how many loops it takes to calculate the squareroot of say 1234567 on the 34S? Is the step length fixed or does it reduce itself closer to convergence (i.e. sign change)? And how did it calculate the initial guess? You might want to have a look at how to calculate the fast inverse square root. But I must admit that I have no idea whether this is used in the WP34s. The algorithm used in most HP calculators is similar to the digitbydigit method you might have learned at school but uses only addition and shifts. Thus just counting the amount of loops isn't enough if you are interested in performance. Kind regards Thomas 

03142014, 06:16 PM
Post: #27




RE: [34S] Time diff. STO.00 vs. STO 00 ?
(03142014 05:34 PM)Thomas Klemm Wrote: But I must admit that I have no idea whether this is used in the WP34s. Meanwhile I had a look at the source code. This comment is from the file wp34scode/decNumber/decNumber.c: Code: /*  */ 

03142014, 09:09 PM
Post: #28




RE: [34S] Time diff. STO.00 vs. STO 00 ?
(03142014 05:34 PM)Thomas Klemm Wrote:(03142014 05:01 PM)Sikuq Wrote: PS: Pauli, is there any way you can test how many loops it takes to calculate the squareroot of say 1234567 on the 34S? Is the step length fixed or does it reduce itself closer to convergence (i.e. sign change)? And how did it calculate the initial guess? Thomas, I thought I had posted a response to you earlier but it appears to have been previewed only  sorry. Thank you for your two posts and the code which I am studying. The inverse function was entirely new to me. I am curious as to just why the loopcycles are not a measure of efficiency given the same accuracy? As I wrote to Pauli I am astounded to learn that the 34S and other computers use the standard Newton tangent way to solve roots, a way I understand is prominent. Zurich I read was voted the most livable city, lucky you. Thanks.  Sikuq 

03172014, 05:12 PM
Post: #29




RE: [34S] Time diff. STO.00 vs. STO 00 ?
(03142014 07:18 AM)Paul Dale Wrote: The majority of the discussions about the numerical accuracy are stored in the old forum archives. There was surprisingly little discussion about this elsewhere. Pauli, I've looked through some of your earlier posts in regards to algorithms. That led me to the square root algorithm by William E. Egbert from HP while working on his HP67 project as described in the HP Journal issue from May 1977. Is that the one you use in the WP34S or is there a better one? It certainly looks like a fast way of getting to the result using only basic WP34S functions.  Sikuq 

03172014, 06:14 PM
Post: #30




RE: [34S] Time diff. STO.00 vs. STO 00 ?
(03172014 05:12 PM)Sikuq Wrote: Is that the one you use in the WP34S or is there a better one? They are not the same: Newton vs. digitbydigit Code: /* decNumberSquareRoot  square root operator */ Cheers Thomas 

03172014, 07:08 PM
Post: #31




RE: [34S] Time diff. STO.00 vs. STO 00 ?
(03172014 06:14 PM)Thomas Klemm Wrote:(03172014 05:12 PM)Sikuq Wrote: Is that the one you use in the WP34S or is there a better one? Thomas, Many thanks. This algorithm stuff gets huge quickly as size is at a premium on WP34S I'd suppose. I'm tempted to keyin the Egbert routines and check convergence times versus the Newton as indicated by you although I have a feeling I would be at a disadvantage using program lines versus precompiled ccode? Am I correct?  Sikuq 

03172014, 07:38 PM
Post: #32




RE: [34S] Time diff. STO.00 vs. STO 00 ?
(03142014 09:09 PM)Sikuq Wrote: I am curious as to just why the loopcycles are not a measure of efficiency given the same accuracy? In case of Newton's method you may not need many iterations but time consuming operations like a division are used. The digitbydigit method may use more cycles but the operations are simple and fast. Thus it really depends on what is going on within that loop. HTH Thomas 

03172014, 08:17 PM
Post: #33




RE: [34S] Time diff. STO.00 vs. STO 00 ?
(03172014 07:38 PM)Thomas Klemm Wrote:(03142014 09:09 PM)Sikuq Wrote: I am curious as to just why the loopcycles are not a measure of efficiency given the same accuracy? Thomas, Thanks for the headsup. It makes me appreciate just how much work they must have done when they stuffed all those algorithms into the WP34S.  Sikuq 

« Next Oldest  Next Newest »

User(s) browsing this thread: 1 Guest(s)