BTW Edwin, I have been away on a trip to Chicago, that is why I am just getting back to you now. I realised a bug
exists in the diff rules on that trip but I am back now and can start to fix it probably tomorrow. It is a pretty
serious bug but it may go unnoticed so it is important to let the list know there is a problem. I just did.
Rich
----- Original Message -----
From: "Edwin Woollett" <woollett at charter.net>
To: "Richard Hennessy" <rvh2007 at comcast.net>
Sent: Wednesday, October 29, 2008 2:06 PM
Subject: Re: pw.mac
Hi Richard,
I like your idea of extending the capability of more Maxima functions in
dealing
with piecewise defined functions, also expressions which used abs(x), etc.
I notice that the fourie.mac package does a pretty good job with dealing
with
abs(x) expressions which I am coming to appreciate more as I finish ch. 7:
symbolic integration.
I think that contributing a preliminary version of pw.mac to the
"source/contrib" section of the
software that one downloads with Maxima would be useful. Much of the code in
"share/contrib"
are "works in progress", and some are being improved gradually by those
interested or the
original contributors.
If you have clear message at the top of your code about your email address
and your
plans for future additions, and an invitation for users to suggest
improvements and/or
additions, this could be a long term benefit to the project.
Use by users gradually could move the concepts into the compiled version,
although
ultimately this would probably involve translations into lisp and maybe
writing some
lisp code from scratch.
The whole concept may not be feasible because of problems of implementing
the
concepts in practice - technical problems no one has thought of yet. But
this is
another argument for gradually seeing what the problems mights be as pw.mac
or other code attempts to make Maxima more user friendly.
As for your negative feedback from some family members, it is never easy to
actively disagree with people who basically have closed minds and think they
have "all the answers". I certainly have experienced some pain from my own
family because of my own gradual departure from a very strict religious and
even "fanatic" environment experienced in my childhood. We can't choose our
parents or other relatives, but we can choose to follow a path of reason,
and
employ the scientific principle of constant skepticism and testing of reason
itself as well
as the enormous number of unfounded assertions floating around in the
culture we find ourselves in.
Ted
----- Original Message -----
From: "Richard Hennessy" <rvh2007 at comcast.net>
To: "'Edwin Woollett'" <woollett at charter.net>
Sent: Tuesday, October 28, 2008 7:06 PM
Subject: pw.mac
Hi Edwin,
If you have time I would like your input on this. I was thinking about
releasing another version of the piecewise functions using unit_step but I
don't think there is a point to that now. There are other things people
will want to do with piecewise functions besides integrating and
differentiating them. Also I am thinking instead of increasing the scope of
the project to include piecewise functions defined with abs(x) instead of
unit_step(x). Or maybe using ceiling() and floor() or min() and max()
functions. Or even signum and plain "if then else" versions. And various
combinations of the above. Also a piecewise solve would be useful, so would
a piecewise transformation to change from abs(x) to unit_step() and visa
versa. And then then is ode2 and odelin. There is a lot here that could be
done. This is just a little bit of it. I am not sure what to do next, but
I may not be happy until I have pw.mac working with many more features than
it has now. If I released anything now I think it would be perceived as so
incomplete as to be not very useful. The opposite extreme is such that it
could take a long time to integrate all of these features. I would like all
Maxima functions to recognize and know what to do with all piecewise
functions, but that may not be reasonable. I am not sure where the right
trade off is. More features later or incremental improvements with periodic
releases as it matures and morphs into something better than what it is now.
It's a hard decision, any ideas are welcome.
Rich
----- Original Message -----
From: Richard Hennessy
To: fateman at cs.berkeley.edu
Sent: Tuesday, October 28, 2008 11:32 AM
Subject: Re: Answering questions
Don't worry about it, I am getting plenty of help from professionals now. I
have been in need of talking about this and bringing it out in the open.
But not on this list, let's not go there.
Rich
----- Original Message -----
From: Richard Fateman
To: 'Richard Hennessy'
Sent: Tuesday, October 28, 2008 11:21 AM
Subject: RE: Answering questions
I suppose there are people with some training in this area who may have some
useful
suggestions. Family counselors.
My own thoughts in this area are more formed from reading novels than
experience or training.
RJF
------------------------------------------------------------------------------
From: Richard Hennessy [mailto:rvh2007 at comcast.net]
Sent: Tuesday, October 28, 2008 7:56 AM
To: fateman at EECS.Berkeley.EDU
Subject: Re: Answering questions
My mothers family was highly religious and they practice shunning. I am
no longer on good terms with them and have had no contact with any member of
her family in over 20 years (basically since my mothers death). My mother
was more educated than the rest of them but even she could not break with
the family religion/tradition completely. I was the first to succeed. My
parent were not as bad as their parents...
Rich
----- Original Message -----
From: Richard Fateman
To: 'Richard Hennessy'
Cc: fateman at cs.berkeley.edu
Sent: Tuesday, October 28, 2008 10:34 AM
Subject: RE: Answering questions
I do not know what motivates your family to feel the way they do. Perhaps
religion.
This kind of attitude is extremely rare among educated people, and I
doubt that
you will find anyone (else?) using sci.math.symbolic for whom this is an
issue.
You can read about the uses and mis-uses of technology, but the idea that
someone who spreads
knowledge of any sort should be shunned is kind of foreign to anyone
exposed to a
normal education.
Good luck
RJF
----------------------------------------------------------------------------
From: Richard Hennessy [mailto:rvh2007 at comcast.net]
Sent: Tuesday, October 28, 2008 6:31 AM
To: Barton Willis; 'Edwin Woollett'; Andrej Vodopivec;
fateman at EECS.Berkeley.EDU; Mario Rodriguez; Robert Dodier
Subject: Re: Answering questions
Also please let me know your thoughts on this privately, some stuff I
don't want to share.
Rich
----- Original Message -----
From: Richard Hennessy
To: Barton Willis ; 'Edwin Woollett' ; Andrej Vodopivec ;
fateman at cs.berkeley.edu ; Mario Rodriguez ; Robert Dodier
Sent: Tuesday, October 28, 2008 9:27 AM
Subject: Answering questions
Hi Guys,
I had to think a lot about this email I am now writing to you but I
think I need to say this. Sometimes when I post to this group I feel like I
am posting my thoughts to the whole world scientific community, or at least
a significant subset of it anyway. One thing I don't like is making enemies
but we in the US have some anyway. Helping them do their homework by doing
it for them or helping with advanced topics makes me nervous.
This is not because I believe Osama Bin Laden is reading these emails
but is instead because many members of my family unfortunately do not like
to spread knowledge _of _any_ _kind_ to our potential enemies and will shun
me if they even _suspect_ that I might be doing that. In actuality my
family members, in general, have no idea what my emails are about and don't
have the faintest idea what I am talking about in my posts. Suffice it to
say that I have had to accept that I will be shunned for the things that I
have done so far. I am not talking about just posts to this group but other
content provided to other people at other times via various media. In
effect I am shunned for life now.
That is not okay with me, but it took a long time to get used to. I am
not complaining now because I got over it. Do you ever get that feeling
making posts to the whole member body? I don't know any top secret stuff so
I am not in the wrong but I do live in a dangerous world and come from a
family that lived though WW 2 and they don't like it. My Uncle has
practically disowned me by now. My dad would too if he was still alive as
would my mom and my brother :(. I am the only one who breaks this rule or
code of conduct in my family. Does this kind of stuff bother anyone else on
this list maybe? I think that people need to open their minds.
In any case I try not to let anyone influence my communications.
Sincerely,
Rich