Greetings and more



#2

Hi, all:

Just returned from Xmas vacations, first thing I do is have a look at this Forum and see the regular mail, where I notice the latest issue of Datafile (V23N6) is waiting for me, and lo and behold, my latest article ("Long Live the HP42S!") is included.

Just in case you're interested, and as a kind of past-due Xmas 'present', I'll send copies of my former Datafile
articles (in PDF format) to anyone requesting them.
Briefly, the articles you may request are:

  • HP-11C: Long Live the HP-11C!

    5-page article, includes an 84-step program which will quickly and accurately find the limit sum of any user-defined infinite alternating series, no matter how slowly it does converge (if at all).

  • HP-12C: Long Live the HP-12C!

    6-page article, includes a 72-step program which will play a challenging game of Bridge-It! against the user.

  • HP-12C: Tried & Tricky Trigonometrics

    10-page article, includes a 99-step program which evaluates all six trigonometric functions (sin, cos, tan and their inverses) very quickly and with full accuracy over an extended range of arguments.

  • HP-12C: Serendipitous Solver

    8-page article, includes a 37-step program which makes use of the built-in machine code solver and a number of financial functions to find a real root of polynomials up to 14th-degree (up to 1480th-degree or more if there are
    groups of repeated coefficients). The program can also evaluate the polynomial for given arguments. Both root
    finding and evaluation are implemented using built-in financial functions. without user-code loops or branching.

  • Time Voyager

    An HP-related short story (11 pages), specifically written to commemorate Sir Isaac Newton.

  • HP-15C: Long Live the HP-15C!

    6-page article, includes a 64-step program which will compute and store the value of Euler's constant e
    (=2.71828+) up to 208 decimal digits, using matrix operations.

  • HP-15C: Nth-degree Polynomial Fitting

    7-page article, includes a 42-step program which will compute explicitly the coefficients of a polynomial of degree
    N (for 2 <= N <= 6), which exactly fits (passes through) a given set of data points (x,y).

  • HP-41C: Long Live the Advantage ROM!

    8-page article, includes the 62-step HP-41C/Advantage ROM version of the HP-15C program featured in HP-15C: Nth-degree Polynomial Fitting, extended to handle degrees much higher than 6, limited only by available RAM.

  • HP-71B: Modest Mater

    12-page article featuring a program that recursively solves arbitrary Mate-in-N chess problems. Fully commented and annotated listing plus examples included.

You can see all of them in HTML format at my web site (except "Modest Mater"), if you wish, but should you want PDF copies of them (identical facsimile to the published article) for storage in a binder or CD-R compilation for example, just send me an e-mail specifying which articles do you want to this address:

and I'll send them attached to my answer to your e-mail (absolutely free, of course !). Keep in mind that each article is some 100-150Kb in size, so you should make sure that your e-mail account has capacity enough to receive them and further, your e-mail server does not remove PDF attachments. The Subject of your e-mail must be "HP CALCS: DATAFILE ARTICLES". This offer is valid till next Monday (2005-01-17)

By the way, I've recently submitted a new batch of articles to Datafile, so you can see them published right now in the very next issues, or else when I eventually make them available at my web site as well, within six months or so.

Best regards from V.


#3

Great website! I like the artciles on the classic HP calculators.


#4

Thank you. I only regret not having enough time (and probably web space) to revamp the ultra-primitive structure of the site and include the tons of pictures and scanned printed materials I have.

Just pictures, I should have several hundreds, of similar quality to the ones featured, and the number of printed pages (program listings, articles, HP brochures, misc) should be in the thousands ... :-(

Perhaps when I retire ...

Best regards from V.


#5

That comment makes me feel very young. I wish I started convincing my parents to buy me more calcualtors when I was a kid (I was born in 1977). But I've been collecting (on and off and on) since 1991.

Believe me, I will be enjoying the ones you put up and look forward to more.

#6

do you know if the pc-1475 can do all its scientific functions to 20 digits, out of interest?

thanks.


#7

Hi, Hugh:

Excuse me but for whatever the reason I completely
missed your post, hence the rather long delay in posting
an answer.

Hugh posted: "do you know if the pc-1475 can do all its scientific functions to 20 digits, out of interest?"

It's been some time since I used this model, which is now
kept sealed and battery-less in my collection,
but I do remember perfectly that at least all arithmetic functions and square roots did produce 20-digit results.

I have the less defined idea that I also did trigs and logs and exponentials with it, and all of them also worked with 20-digit accuracy, else I would have noticed it at once, which I don't remember was ever the case, so I am 90% sure that yes, all standard elementary functions do work to 20-digit precision as well.

On the negative side, I also extensively tried the built-in matrix functions, and though they were very fast, accurate, and easy to use, they did not work with double precision, 20-digit variables, just 10-digit ones, which is a real pity.

When I take this machine out of its sealed envelope for its periodic check, I'll test all of this much more thoroughly.

Best regards from V.

#8

Back in July 2004 you wrote that you were writing programs which would solve "7x7 system of linear equations in an HP-67, a 12x12 tridiagonal system of equations, invert a 5x5 matrix in place, or do 4x4 matrix operations within a single program, ...". Are those programs in your latest submission to DATAFILE?


#9

Hi, Palmer:

Palmer posted: "Back in July 2004 you wrote that you were writing programs which would solve "7x7 system of linear equations in an HP-67, a
12x12 tridiagonal system of equations, invert a 5x5 matrix in place, or do 4x4 matrix operations within a single program, ...". Are
those programs in your latest submission to DATAFILE?"

Matter of fact, no, the three latest articles I've sent are focused on other HP models, not the HP-67, but the ones you mention can indeed be sent for eventual publication in a near future issue.

To set the record straight, I weren't writing those programs back in July 2004, said programs were written, debugged and documented some 20+ years ago, but as far as I recall they haven't been published anywhere, with the possible exception of the 7x7 system which might haven been (though I can't remember where or when). Also, the 7x7 program was written by my friend Fernando del Rey, the 4x4 and 5x5 programs were written by me, and I can't remember who wrote the 12x12 program, whether he or me. Both could be the author, our
programming styles are quite similar. :-)

Thanks for your interest and best regards from V.


#10

Palmer has done quite a bit of work with matrix solving routines for accuracy.

So far, it appears that the TI-59 is still quite a bit ahead of most of the competition. :-)


Forum Jump: