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On May 30, 8:02 pm, kwikius <a...@servocomm.freeserve.co.uk> wrote:
> On May 30, 10:18 am, James Kanze <james.ka...@gmail.com> wrote:

> > On May 30, 6:00 am, "kwikius" <a...@servocomm.freeserve.co.uk> wrote:

> > > quan
> > >http://tinyurl.com/5lxb3s
> > > std
> > >http://tinyurl.com/6k9b7f
> > > hmm... something smells a bit whiffy ..

> > Sorry, but I don't follow you. What's the relationship
> > between the two?

> The duration type is pretty much of an exact replica of the quan
> quantity.

The duration type is pretty much a simple example of a classical
"units" type. The first time I saw something along those lines
was at least 15 years ago. It's hardly a new idea. (I actually
suspect that it's been "invented" independently many times.)

> From the text the impression one gets is that the design is
> basically that of Jeff Garland boost date time lib, with
> some vague reference to Walter Brown, presumably SI units
> library and implementation by Howard Hinnant.

The actual design did start out with something from Boost. I'm
pretty sure of that. Where the author of Boost got his ideas, I
don't know, but I don't see any reason to think that they come
from some library no one has basically heard of. (The
references in the Boost documentation cite some 10 or 15
different libraries. Presumably if quan had played a role, it
would be cited there as well.)

> I believe Walter Brown used compile time rational numbers [1]
> in SIUnits, as did Barton & Nackman, but they only used
> compile time rationals for dimensional analysis, not
> conversion factors (meter to millimeters etc).

As I said, I have been aware of this possibility for at least 15
years. And while I don't know of its relationship with Walter's
SIUnits, I do know that a class with this name was available
publicly over ten years ago. (But Walter could just as easily
have come up with the same thing---and the name is rather
obvious.)

> The original use of compile time rationals for the units was
> AFAIK my pqs library, the forerunner of my quan library in the
> above link. (Originally pqs used 2 separate compile time
> integers, but it was Brandon Forehand that pointed out that
> they were in fact acting as a rational number, and pqs was
> subsequently modified accordingly).

I'm not too sure what you mean by "compile time rationals", but
libraries which would support assigning meters to millimeters,
for example, with automatic scaling, are not particularly new.

> In fact Mr Garland did use conversion factors in his boost
> date time lib, but used runtime scaling (in an explicit ctor
> at least in boost_1.33.0), all values were kept internally in
> milliseconds in a base class.

I've seen both techniques, both many years ago. I think both
date back to the early days of Algol.

--
James Kanze (GABI Software) email:
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On 2008-05-31 10:49, James Kanze wrote:
> On May 30, 8:02 pm, kwikius <a...@servocomm.freeserve.co.uk> wrote:
>> On May 30, 10:18 am, James Kanze <james.ka...@gmail.com> wrote:
>
>> > On May 30, 6:00 am, "kwikius" <a...@servocomm.freeserve.co.uk> wrote:
>
>> > > quan
>> > >http://tinyurl.com/5lxb3s
>> > > std
>> > >http://tinyurl.com/6k9b7f
>> > > hmm... something smells a bit whiffy ..
>
>> > Sorry, but I don't follow you. What's the relationship
>> > between the two?
>
>> The duration type is pretty much of an exact replica of the quan
>> quantity.
>
>> From the text the impression one gets is that the design is
>> basically that of Jeff Garland boost date time lib, with
>> some vague reference to Walter Brown, presumably SI units
>> library and implementation by Howard Hinnant.
>
>> I believe Walter Brown used compile time rational numbers [1]
>> in SIUnits, as did Barton & Nackman, but they only used
>> compile time rationals for dimensional analysis, not
>> conversion factors (meter to millimeters etc).
>
>> In fact Mr Garland did use conversion factors in his boost
>> date time lib, but used runtime scaling (in an explicit ctor
>> at least in boost_1.33.0), all values were kept internally in
>> milliseconds in a base class.

Ok, so according to you at least two of the authors have some previous
experiences with writing unit libraries, and a quick search reveals that
at least one more (Marc Paterno) uses C++ for physics simulation. And
you somehow find it strange that together they manage to slightly evolve
some of their previous work? I mean, the step from run-time scaling to
compile-time is not that large.

--
Erik Wikström

On May 31, 10:20*am, Erik Wikström <Erik-wikst...@telia.com> wrote:


> I mean, the step from run-time scaling to
> compile-time is not that large.

Yep Its a tiny step, but (though I say so myself) ... brilliant and
renders the old technique redundant because its both faster and more
accurate.

SIUnits ( fermilab --> Walter Brown, hence Marc Patterno <--fermilab)
has been around for many years and they didnt figure it out, their
approach loses precision and is slow.

Makes em look pretty stupid don't it... ?

Of course when you explain the technique everybody says... well thats
obvious..I could have thought of that...

Difference is ... I Did think of that.

Now it seesm there is a lot of other people running around trying to
slyly imply that They thought of it.



regards
Andy Little

On May 31, 9:49*am, James Kanze <james.ka...@gmail.com> wrote:

> I'm not too sure what you mean by "compile time rationals", but
> libraries which would support assigning meters to millimeters,
> for example, with automatic scaling, are not particularly new.

No offence intended Mr Kanze, but if you don't know what a "compile
time rational" is then you really arent qualified to say that the
technique is "particularly new" or not.

regards
Andy Little

On May 31, 3:13 pm, kwikius <a...@servocomm.freeserve.co.uk> wrote:
> On May 31, 9:49 am, James Kanze <james.ka...@gmail.com> wrote:

> > I'm not too sure what you mean by "compile time rationals",
> > but libraries which would support assigning meters to
> > millimeters, for example, with automatic scaling, are not
> > particularly new.

> No offence intended Mr Kanze, but if you don't know what a
> "compile time rational" is then you really arent qualified to
> say that the technique is "particularly new" or not.

I'm willing to believe that you may have invented the term, but
all of the techniques described in the standard document you
cited have been known for at least fifteen years. As I said,
from what I've read, I gather that they were being considered
when the original Algol standard was proposed, and I've
definitely discussed them with people in email some ten or
fifteen years ago. I also believe that they are "obvious"
enough that they have probably been independently reinvented
many times.

--
James Kanze (GABI Software) email:
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
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On Jun 1, 1:10*am, James Kanze <james.ka...@gmail.com> wrote:
> On May 31, 3:13 pm, kwikius <a...@servocomm.freeserve.co.uk> wrote:
>
> > On May 31, 9:49 am, James Kanze <james.ka...@gmail.com> wrote:
> > > I'm not too sure what you mean by "compile time rationals",
> > > but libraries which would support assigning meters to
> > > millimeters, for example, with automatic scaling, are not
> > > particularly new.
> > No offence intended Mr Kanze, but if you don't know what a
> > "compile time rational" is then you really arent qualified to
> > say that the technique is "particularly new" or not.
>
> I'm willing to believe that you may have invented the term,

...

I didnt invent the term, nor claim to have "invented" the compile time
rational.

<...>

> *I also believe that they are "obvious"
> enough that they have probably been independently reinvented
> many times.

Oh Yes.. there's certainly been a fair amount of "reinvention" going
on



Your animation is quite understandable. After all you inhabit the same
brotherhood as the people that wrote the paper.

I actually now just find this whole business very amusing, well ...
and somewhat sad. The truth is the truth and well documented over a
period of some yers for any one that cares to look. What I find
fascinating now is the amount of FUD that has been shoved around.

I wrote pqs, the forerunner to quan to solve a simple problem, because
I spent a long time looking for a physical quantities library but none
met my needs. No one had written a library with the "obvious"
solution, which I found surprising as it is indeed obvious as you
say...

well OTOH everything is obvious once it has been demonstrated aint
it

regards
Andy Little

On Jun 1, 4:40 am, kwikius <a...@servocomm.freeserve.co.uk> wrote:
> On Jun 1, 1:10 am, James Kanze <james.ka...@gmail.com> wrote:

> <...>

> > I also believe that they are "obvious" enough that they have
> > probably been independently reinvented many times.

> Oh Yes.. there's certainly been a fair amount of "reinvention"
> going on

>

> Your animation is quite understandable. After all you inhabit
> the same brotherhood as the people that wrote the paper.

What brotherhood is that? I'm certainly not involved in any way
with Boost (although I like a lot---but not everything---of what
they do). And in the standards committee, my activity is mostly
in the language section, and except for threading and garbage
collection, exclusively involved with improving existing
elements. Of the authors, I've meant Howard once, Walter and I
are old sparring partners (because I rather think that D is a
waste of time), and I've never even heard of the other two.

> I actually now just find this whole business very amusing,
> well ... and somewhat sad. The truth is the truth and well
> documented over a period of some years for any one that cares
> to look.

You mean like the proposals for Units in Algol.

--
James Kanze (GABI Software) email:
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
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On Jun 1, 10:34*am, James Kanze <james.ka...@gmail.com> wrote:
> On Jun 1, 4:40 am, kwikius <a...@servocomm.freeserve.co.uk> wrote:

<...>

> What brotherhood is that? *I'm certainly not involved in any way
> with Boost (although I like a lot---but not everything---of what
> they do). *And in the standards committee, my activity is mostly
> in the language section, and except for threading and garbage
> collection, exclusively involved with improving existing
> elements. *Of the authors, I've meant Howard once, Walter and I
> are old sparring partners (because I rather think that D is a
> waste of time), and I've never even heard of the other two.

err.. hmm... Walter E. Brown, Fermilab, author of SIUnits ... not
Walter Bright, C++ innovator and author of D, nor even Walter Banks..
extender of C, Bytecraft.

> > I actually now just find this whole business very amusing,
> > well ... *and somewhat sad. The truth is the truth and well
> > documented over a period of some years for any one that cares
> > to look.
>
> You mean like the proposals for Units in Algol.

That sounds like a lot of fun ... but Without a link to the
details its FUD and handwaving, so... Care to provide a link to these
proposals?

And BTW If anyone can provide good evidence of prior art ( solid
evidence, not handwaving) in relation to the mechanisms of Units
conversion in Quan, please don't hold back... I have spent a fair
amount of time researching this subject and so far havent found
anything similar prior to pqs the predecessor to quan, despite the
fact that After I published it everybody seems to say how obvious it
is...

Obvious ? Sure.. except that that no one actually seems to have done
it ... before I did.

Now there seem to be peple trying to slyly give the impression that
its all their idea, without actually making a definitive statement
(funnily enough some of the same people coincidentally having dished a
lot of dirt out in relation to me and my work.).

Essentially theres a lot of people trying to pretend I and Quan don't
exist, and that is downright offensive.

regards
Andy Little

On Jun 1, 4:01 pm, kwikius <a...@servocomm.freeserve.co.uk> wrote:
> On Jun 1, 10:34 am, James Kanze <james.ka...@gmail.com> wrote:

> > On Jun 1, 4:40 am, kwikius <a...@servocomm.freeserve.co.uk> wrote:

> <...>

> > What brotherhood is that? I'm certainly not involved in any way
> > with Boost (although I like a lot---but not everything---of what
> > they do). And in the standards committee, my activity is mostly
> > in the language section, and except for threading and garbage
> > collection, exclusively involved with improving existing
> > elements. Of the authors, I've meant Howard once, Walter and I
> > are old sparring partners (because I rather think that D is a
> > waste of time), and I've never even heard of the other two.

> err.. hmm... Walter E. Brown, Fermilab, author of SIUnits ...
> not Walter Bright, C++ innovator and author of D, nor even
> Walter Banks.. extender of C, Bytecraft.

Oops.

> > > I actually now just find this whole business very amusing,
> > > well ... and somewhat sad. The truth is the truth and well
> > > documented over a period of some years for any one that cares
> > > to look.

> > You mean like the proposals for Units in Algol.

> That sounds like a lot of fun ... but Without a link to
> the details its FUD and handwaving, so... Care to provide a
> link to these proposals?

I'm afraid the Web wasn't used much back in the early days of
Algol.

[...]
> Now there seem to be peple trying to slyly give the impression
> that its all their idea,

Actually, you seem to be the only one claiming its their idea.
All of the others seem to consider it as more or less usual
practice.

--
James Kanze (GABI Software) email:
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
9 place Sémard, 78210 St.-Cyr-l'École, France, +33 (0)1 30 23 00 34

On Jun 1, 9:24*pm, James Kanze <james.ka...@gmail.com> wrote:

> Actually, you seem to be the only one claiming its their idea.

Thats because it is my idea.

regards
Andy Little