20 Mar
2020
20 Mar
'20
3:03 p.m.
From: Paul Guertin
I teach math in college ... Sometimes, during an exam,
a student who
forgot to bring their calculator will ask if they can borrow mine I
always say "sure, but you'll regret it" and hand them the calculator
After wasting one or two minutes, they give it back
Maybe I'm being clueless/over-asking, but to me it's appalling that any
college student (at least all who have _any_ math requirement at all; not sure
how many that is) doesn't know how an RPN calculator works. It's not exactly
rocket science, and any reasonably intelligent high-schooler should get it
extremely quickly; just tell them it's just a representational thing, number
number operator instead of number operator number. I know it's not a key
intellectual skill, but it does seem to me to be part of comon intellectual
heritage that everyone should know, like musical scales or poetry
rhyming. Have you ever considered taking two minutes (literally!) to cover it
briefly, just 'someone tried to borrow my RPN calculator, here's the basic
idea of how they work'?
Noel
20 Mar
20 Mar
3:08 p.m.
New subject: The most surprising Unix programs
A cool thing about tools is that you never know how it will be used.
Bach's prelude in C major from Well-Tempered Clavier book I, written in
pure (GNU) sed: https://github.com/laserbat/bach.sed
3:52 p.m.
New subject: The most surprising Unix programs
On Fri, Mar 20, 2020 at 10:08:50AM -0400, Richard Salz wrote:
A cool thing about tools is that you never know how it
will be used.
Bach's prelude in C major from Well-Tempered Clavier book I, written in
pure (GNU) sed: https://github.com/laserbat/bach.sed
If someone understands how this all works, my less capable brain would
love an explanation. My dad and my kid have told me that classical
music is math but I've never seen it. Seems like this is probably
the example I need.
3:58 p.m.
New subject: The most surprising Unix programs
Hi Larry,
Am 20.03.2020 um 15:52 schrieb Larry McVoy <lm(a)mcvoy.com>:
If someone understands how this all works, my less
capable brain would
love an explanation. My dad and my kid have told me that classical
music is math but I've never seen it. Seems like this is probably
the example I need.
For this topic I’d recommend the excellent book "Gödel, Escher, Bach:
An Eternal Golden Braid“ from Douglas R. Hofstadter which discusses
the relationship especially between Bach and math and also gives a
nice introduction into logic and philosopy.
Best regards — Dago
--
"You don't become great by trying to be great, you become great by wanting to do
something,
and then doing it so hard that you become great in the process." - xkcd #896
4:05 p.m.
New subject: The most surprising Unix programs
It reads a text stream and outputs commands to drive a MIDI player.
11:09 p.m.
New subject: The most surprising Unix programs
I quoted Hofstadter's sage words in my dissertation intro:
Hofstadter’s Law: It always takes longer than
you expect, even when you take into account
Hofstadter’s Law.
Mike Markowski
On 3/20/20 10:58 AM, Dagobert Michelsen wrote:
...For this topic I’d recommend the excellent book
"Gödel, Escher, Bach:
An Eternal Golden Braid“ from Douglas R. Hofstadter which discusses
the relationship especially between Bach and math and also gives a
nice introduction into logic and philosopy.
Best regards — Dago
4:03 p.m.
New subject: The most surprising Unix programs
Hello!
Actually it is. Some years ago a chap wrote a book comparing Bach,
(who has a birth anniversary tomorrow), and that artist who draws
illusions and another mathematician as well.It caused an even bigger
upset then the OS we discuss here.
-----
Gregg C Levine gregg.drwho8(a)gmail.com
"This signature fought the Time Wars, time and again."
On Fri, Mar 20, 2020 at 10:53 AM Larry McVoy <lm(a)mcvoy.com> wrote:
On Fri, Mar 20, 2020 at 10:08:50AM -0400, Richard Salz wrote:
A cool thing about tools is that you never know
how it will be used.
Bach's prelude in C major from Well-Tempered Clavier book I, written in
pure (GNU) sed: https://github.com/laserbat/bach.sed
If someone understands how this all works, my less capable brain would
love an explanation. My dad and my kid have told me that classical
music is math but I've never seen it. Seems like this is probably
the example I need. 
4:05 p.m.
New subject: The most surprising Unix programs
On 3/20/20 11:03 AM, Gregg Levine wrote:
Hello!
Actually it is. Some years ago a chap wrote a book comparing Bach,
(who has a birth anniversary tomorrow), and that artist who draws
illusions and another mathematician as well.It caused an even bigger
upset then the OS we discuss here.
One of the best books I read in high school. I loved it.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU chet(a)case.edu http://tiswww.cwru.edu/~chet/
11:06 p.m.
New subject: The most surprising Unix programs
On Fri, 20 Mar 2020, Larry McVoy wrote:
"Gödel, Escher, Bach: An Eternal Golden Braid" by Douglas Hofstadter would
be a good introduction too.
-- Dave
Bach's
prelude in C major from Well-Tempered Clavier book I, written in
pure (GNU) sed: https://github.com/laserbat/bach.sed
If someone understands how this all works, my less capable brain would
love an explanation. My dad and my kid have told me that classical
music is math but I've never seen it. Seems like this is probably
the example I need. 
21 Mar
21 Mar
5:59 a.m.
New subject: The most surprising Unix programs
In a word: ratios. Each note is in a ratio to each other note being
played, either after, while, or after it is being played. It's called
the harmonic or overtone series, and if you've ever looked at a
half-way decent brass instrument method/tutor, you'll have seen it in
all its glory. The nicer-sounding ratios are the ones usually used -
the octaves, the fifths, the fourths and the thirds. The others, the
sixths, the sevenths and the seconds, tend to clash more and/or add a
mournful tone to the music.
https://www.howmusicreallyworks.com/Pages_Chapter_3/3_2.html
Chapter 3:
How Tones and Overtones REALLY Work
gives a non-technical but mathematically sound description: table 4 is
worth its weight in platinum.
Wesley Parish
On 3/21/20, Larry McVoy <lm(a)mcvoy.com> wrote:
On Fri, Mar 20, 2020 at 10:08:50AM -0400, Richard Salz
wrote:
A cool thing about tools is that you never know
how it will be used.
Bach's prelude in C major from Well-Tempered Clavier book I, written in
pure (GNU) sed: https://github.com/laserbat/bach.sed
If someone understands how this all works, my less capable brain would
love an explanation. My dad and my kid have told me that classical
music is math but I've never seen it. Seems like this is probably
the example I need.
20 Mar
20 Mar
10:57 p.m.
New subject: The most surprising Unix programs
On Fri, 20 Mar 2020, Richard Salz wrote:
A cool thing about tools is that you never know how it
will be used.
Indeed. I once wrote a shell script that basically acted as an n-way
"cut" i.e. you specify the columns you wanted to extract and they ended up
on the corresponding file descriptors. Ran into all sorts of bugs, as the
"obvious" solution didn't work.
Bach's prelude in C major from Well-Tempered
Clavier book I, written in pure
(GNU) sed: https://github.com/laserbat/bach.sed
I have the Towers of Hanoi written in sendmail.cf, meaning that Sendmail
is Turing-complete :-) I can't remember who wrote it.
-- Dave
22 Mar
22 Mar
7:05 p.m.
New subject: The most surprising Unix programs
Dave Horsfall <dave(a)horsfall.org> wrote:
I have the Towers of Hanoi written in sendmail.cf, meaning that Sendmail is
Turing-complete :-) I can't remember who wrote it.
Jonathan Chin: http://www.jhnc.org/hanoi/sendmail-cf.html
It's really easy to fall into the Turing tar-pit, if you have a loop
around regex-based rewriting - and unix mailers often have routing logic
that includes features for rewriting an address and re-routing it.
Tony.
--
f.anthony.n.finch <dot(a)dotat.at> http://dotat.at/
Thames, Dover: East or southeast 5 to 7, occasionally 4 later. Slight or
moderate. Fair. Good.
20 Mar
20 Mar
4:07 p.m.
New subject: The most surprising Unix programs
On 20/03/2020, Noel Chiappa <jnc(a)mercury.lcs.mit.edu> wrote:
From: Paul
Guertin
I teach math in college ... Sometimes, during an
exam, a student who
forgot to bring their calculator will ask if they can borrow mine I
always say "sure, but you'll regret it" and hand them the calculator
After wasting one or two minutes, they give it back
[,,,] [...] and any reasonably intelligent high-schooler
should get it
extremely quickly; just tell them it's just a representational thing,
number number operator instead of number operator number.
A former colleague -- electronics engineer, to boot -- told me that he
refuses to use RPN calculators because one will not always be
available and he does not want to become "dependent" on it.
Offsetting that, my wife -- who does not work in a technical field --
swears by her 32S (and still has her 35 somewhere). I have my
caculators on my Macs all set to RPN.
Perhaps a bit mean of me, but when people were befuddled, I used to
say that my calculators used "natural" input.
N.
8:03 p.m.
New subject: The most surprising Unix programs
On Mar 20, 2020, at 8:07 AM, Nemo
<cym224(a)gmail.com> wrote:
Offsetting that, my wife -- who does not work in a technical field --
swears by her 32S (and still has her 35 somewhere). I have my
caculators on my Macs all set to RPN.
You can have my HP-28S when you pry it from my cold dead hands.
Adam
5:07 p.m.
New subject: The most surprising Unix programs
+COFF
On 3/20/20 8:03 AM, Noel Chiappa wrote:
Maybe I'm being clueless/over-asking, but to me
it's appalling that
any college student (at least all who have _any_ math requirement at
all; not sure how many that is) doesn't know how an RPN calculator
works.
I'm sure that there are some people, maybe not the corpus you mention,
that have zero clue how an RPN calculator works. But I would expect
anybody with a little gumption to be able to poke a few buttons and
probably figure out the basic operation, or, ask if they are genuinely
confused.
It's not exactly rocket science, and any
reasonably intelligent
high-schooler should get it extremely quickly; just tell them it's
just a representational thing, number number operator instead of
number operator number.
I agree that RPN is not rocket science. And for basic single operation
equations, I think that it's largely interchangeable with infix notation.
However, my experience is, as the number of operations goes up, RPN can
become more difficult to use. This is likely a mental shortcoming on my
part. But it is something that does take tractable mental effort for me
to do.
For example, let's start with Pythagorean Theorem
a² + b² = c²
This is relatively easy to enter in infix notation on a typical
scientific calculator.
However, I have to stop and think about how to enter this on an RPN
calculator. I'll take a swing at this, but I might get it wrong, and I
don't have anything handy to test at the moment.
[a] [enter]
[a] [enter]
[multiply]
[b] [enter]
[b] [enter]
[multiply]
[add]
[square root] # to solve for c
(12 keys)
Conversely infix notation for comparison.
[a]
[square]
[plus]
[b]
[square]
[square root]
(6 keys)
As I type this, I realize that I'm using higher order operations
(square) in infix than I am in RPN. But that probably speaks to my
ignorance of RPN.
I also realize that this equation does a poor job at demonstrating what
I'm trying to convey. — Or perhaps what I'm trying to convey is
incorrect. — I had to arrange sub-different parts of the equation so
that their results ended up together on the stack for them to be the
targets of the operation. I believe this (re)arrangement of the
equation is where most of my mental load / objection comes from with
RPN. I feel like I have to process the equation before I can tell the
calculator to compute the result for me. I don't feel like I have this
burden with infix notation.
Aside: I firmly believe that computers are supposed to do our bidding,
not the other way around. s/computers/calculators/
I know it's not a key intellectual skill, but it
does seem to me to
be part of comon intellectual heritage that everyone should know,
like musical scales or poetry rhyming. Have you ever considered
taking two minutes (literally!) to cover it briefly, just 'someone
tried to borrow my RPN calculator, here's the basic idea of how they
work'?
I'm confident that 80% of people, more of the corpus you describe, could
use an RPN calculator to do simple equations. But I would not be
surprised if many found that the re-arrangement of equations to being
RPN friendly would simply forego the RPN calculator for simpler
arithmetic operations.
I think some of it is a mental question: Which has more mental load,
doing the annoying arithmetic or re-arranging to use RPN.
I believe that for the simpler of the arithmetic operations, RPN is
going to be more difficult.
All of this being said, I'd love to have someone lay out points and / or
counterpoints to my understanding.
--
Grant. . . .
unix || die
13 Sep
13 Sep
5:44 p.m.
New subject: The most surprising Unix programs
Grant Taylor via TUHS <tuhs(a)minnie.tuhs.org> writes:
For example, let's start with Pythagorean
Theorem
a² + b² = c²
[...]
[a] [enter]
[a] [enter]
[multiply]
[b] [enter]
[b] [enter]
[multiply]
[add]
[square root] # to solve for c
I do
[a] [square]
[b] [square]
[plus]
[square root]
6 keys. (Many operations push the entered value into the x register
without needing the enter key. Also, like with infix calculators,
usually there is a [x^2] key -- in postfix notation on both!)
[a]
[square]
[plus]
[b]
[square]
[square root]
That would give you the value of [b] and leave some rest of the
operation in the (hidden) registers. Actually you need
[a] [square]
[plus]
[b] [square]
[=]
[square root]
7 keys.
Although I started with infix calculators, I find it easier to work
my way out of more complex nested formulas with RPN than to track
the level of parentheses in my mind. Consider something like this:
3y * x / (z + 4k)^2 2w + v! \
------ * | ---------- + ---------- |
5b + z \ 3b * 4x ln(x + 2y) /
Now this is a PITA either way, but it comes easier for me with RPN.
[Sorry for the late reply -- I subscribed to TUHS earlier this year
and am only now making my way through it.]
--
Kein Wunder, wenn bei Leuten, die tagaus, tagein Zugriff auf alles
haben, was die Welt im Internet anbietet, die Fantasie-Sicherungen
durchbrennen. -- Karl Notter
1514
days inactive
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15 comments
14 participants
participants (14)
-
Adam Thornton -
Chet Ramey -
Dagobert Michelsen -
Dave Horsfall -
Grant Taylor -
Gregg Levine -
jnc＠mercury.lcs.mit.edu -
Juergen Nickelsen -
Larry McVoy -
Mike Markowski -
Nemo -
Richard Salz -
Tony Finch -
Wesley Parish