• #### Whither Lee Dickey (or APL Archivist)?

From Doug White@21:1/5 to All on Tue Dec 15 21:52:08 2020
Prof. Paul Penfield and I have a website of APL material based on his
circuit analysis extensions to APL called MARTHA
(http://www.marthallama.org/). Paul & I aren't getting any younger, and
(as far as I know) visits to the website are now very few & far between.
I was thinking it would be good to find a more permanent home for the
material.

I tried to contact Prof. Lee Dickey at the email address provided at the
APL Archive website he maintained at the University of Waterloo. After
several days, I just got an email delivery failure notice.

Does anyone know if Prof. Dickey is still maintaining the archives? If
so, any idea how best to get in touch with him?

If the Waterloo archives are no longer being supported, is there another repository we can consider?

Thanks!

Doug White

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• From Stefano Lanzavecchia@21:1/5 to Doug White on Wed Dec 16 06:27:10 2020
On Tuesday, 15 December 2020 at 22:52:10 UTC+1, Doug White wrote:
Prof. Paul Penfield and I have a website of APL material based on his circuit analysis extensions to APL called MARTHA (http://www.marthallama.org/).

I read in the brochure: "What kinds of circuits does MARTHA handle? Linear circuits..."

Since I studied very little electronic in my life and even that was more than 25 years ago, I had to ask wikipedia for help (https://en.wikipedia.org/wiki/Linear_circuit) from which I quote: "
A linear circuit is an electronic circuit which obeys the superposition principle.[1][2][3] This means that the output of the circuit F(x) when a linear combination of signals ax1(t) + bx2(t) is applied to it is equal to the linear combination of the
outputs due to the signals x1(t) and x2(t) applied separately:

{\displaystyle F(ax_{1}+bx_{2})=aF(x_{1})+bF(x_{2})\,}F(ax_{1}+bx_{2})=aF(x_{1})+bF(x_{2})\,
It is called a linear circuit because the output of such a circuit is a linear function of its inputs.[1][2][3]
"

Right. That's a definition which I like because, as a physicist, I was thoroughly drilled on linear functions.

Then I read in the brochure: "MARTHA includes, besides R, L, and C, sixteen controlled sources; operational amplifiers; mutual inductance; three transistor models and the possibility of easily creating others; ideal transformers; several composite pi and
tee structures; and a few exotic elements such as gyrators."

Hold on a second: I thought that transistors were non-linear components. And, in fact, Wikipedia says:
"
A linear circuit is one that has no nonlinear electronic components in it.[1][2][3] Examples of linear circuits are amplifiers, differentiators, and integrators, linear electronic filters, or any circuit composed exclusively of ideal resistors,
capacitors, inductors, op-amps (in the "non-saturated" region), and other "linear" circuit elements.

Some examples of nonlinear electronic components are: diodes, transistors, and iron core inductors and transformers when the core is saturated. Some examples of circuits that operate in a nonlinear way are mixers, modulators, rectifiers, radio receiver
detectors and digital logic circuits.
"

Maybe the apparent contradiction comes from the fact that the models available in Martha are only considered in their linear region? Also, it is possible that the full documentation goes to major length about the actual definitions. If so, forgive my
laziness.

All the best,
--
Stefano

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• From Kerry Liles@21:1/5 to Doug White on Wed Dec 16 15:49:10 2020
Doug White wrote:

Prof. Paul Penfield and I have a website of APL material based on his
circuit analysis extensions to APL called MARTHA (http://www.marthallama.org/). Paul & I aren't getting any younger, and
(as far as I know) visits to the website are now very few & far between.
I was thinking it would be good to find a more permanent home for the material.

I tried to contact Prof. Lee Dickey at the email address provided at the
APL Archive website he maintained at the University of Waterloo. After several days, I just got an email delivery failure notice.

Does anyone know if Prof. Dickey is still maintaining the archives? If
so, any idea how best to get in touch with him?

If the Waterloo archives are no longer being supported, is there another repository we can consider?

Thanks!

Doug White

No idea about Prof. Dickey but perhaps this would be an opportunity for Dyalog to step up and offer an archival site? Of course, it is easy for me to suggest other people do things for free, but Dyalog seems to be the largest company to offer APL related software etc.

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• From Kerry Liles@21:1/5 to Doug White on Wed Dec 16 16:10:43 2020
Doug White wrote:

Prof. Paul Penfield and I have a website of APL material based on his
circuit analysis extensions to APL called MARTHA (http://www.marthallama.org/). Paul & I aren't getting any younger, and
(as far as I know) visits to the website are now very few & far between.
I was thinking it would be good to find a more permanent home for the material.

I tried to contact Prof. Lee Dickey at the email address provided at the
APL Archive website he maintained at the University of Waterloo. After several days, I just got an email delivery failure notice.

Does anyone know if Prof. Dickey is still maintaining the archives? If
so, any idea how best to get in touch with him?

If the Waterloo archives are no longer being supported, is there another repository we can consider?

Thanks!

Doug White

Searching the Uwaterloo.ca website revealed this:

https://uwaterloo.ca/pure-mathematics/people-profiles/leroy-j-dickey

http://www.math.uwaterloo.ca/~ljdickey/

HTH

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• From Doug White@21:1/5 to Stefano Lanzavecchia on Thu Dec 17 21:51:33 2020
Yes, in the case of transistors, they are simulated with a "small
signal" linear model. The transistor parameters are calcualted at a
specific bias condition ("operating point").

There was a more advanced workspace developed later that can deal with non-linear problems using Volterra series. I think that work was done
as a thesis by one of Prof. Penfield's students. I never worked with
it, and only have a dim recollection of the details.

Doug White

Stefano Lanzavecchia <stefano.lanzavecchia@gmail.com> wrote in news:c9eee738-1f52-49cd-8e59-519e5c553289n@googlegroups.com:

On Tuesday, 15 December 2020 at 22:52:10 UTC+1, Doug White wrote:
Prof. Paul Penfield and I have a website of APL material based on his
circuit analysis extensions to APL called MARTHA
(http://www.marthallama.org/).

about Prof. Dickey, but I have a curiosity about the project itself.
I read in the brochure: "What kinds of circuits does MARTHA handle?
Linear circuits..."

Since I studied very little electronic in my life and even that was
more than 25 years ago, I had to ask wikipedia for help (https://en.wikipedia.org/wiki/Linear_circuit) from which I quote: "
A linear circuit is an electronic circuit which obeys the
superposition principle.[1][2][3] This means that the output of the
circuit F(x) when a linear combination of signals ax1(t) + bx2(t) is
applied to it is equal to the linear combination of the outputs due to
the signals x1(t) and x2(t) applied separately:

{\displaystyle F(ax_{1}+bx_{2})=aF(x_{1})+bF(x_{2})\,}F(ax_{1}+bx_{2})=aF(x_{1})+bF
(x_
{2})\, It is called a linear circuit because the output of such a
circuit is a linear function of its inputs.[1][2][3] "

Right. That's a definition which I like because, as a physicist, I was thoroughly drilled on linear functions.

Then I read in the brochure: "MARTHA includes, besides R, L, and C,
sixteen controlled sources; operational amplifiers; mutual inductance;
three transistor models and the possibility of easily creating others;
ideal transformers; several composite pi and tee structures; and a few
exotic elements such as gyrators."

Hold on a second: I thought that transistors were non-linear
components. And, in fact, Wikipedia says: "
A linear circuit is one that has no nonlinear electronic components in it.[1][2][3] Examples of linear circuits are amplifiers,
differentiators, and integrators, linear electronic filters, or any
circuit composed exclusively of ideal resistors, capacitors,
inductors, op-amps (in the "non-saturated" region), and other "linear" circuit elements.

Some examples of nonlinear electronic components are: diodes,
transistors, and iron core inductors and transformers when the core is saturated. Some examples of circuits that operate in a nonlinear way
digital logic circuits. "

Maybe the apparent contradiction comes from the fact that the models available in Martha are only considered in their linear region? Also,
it is possible that the full documentation goes to major length about
the actual definitions. If so, forgive my laziness.

All the best,
--
Stefano

--
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• From Doug White@21:1/5 to Kerry Liles on Thu Dec 17 21:56:14 2020
Thanks for the links. The email address they give is the same one I
tired. Between COVID, the Holidays and being emeriitus, he may not be
checkign his email that often.

If I don't hear anything in a while, I can try calling his office.

Doug White

"Kerry Liles" <kerry.liles@gmail.com> wrote in
news:rrdbi3\$q8q\$1@dont-email.me:

Doug White wrote:

Prof. Paul Penfield and I have a website of APL material based on his
circuit analysis extensions to APL called MARTHA
(http://www.marthallama.org/). Paul & I aren't getting any younger,
and (as far as I know) visits to the website are now very few & far
between. I was thinking it would be good to find a more permanent
home for the material.

I tried to contact Prof. Lee Dickey at the email address provided at
the APL Archive website he maintained at the University of Waterloo.
After several days, I just got an email delivery failure notice.

Does anyone know if Prof. Dickey is still maintaining the archives?
If so, any idea how best to get in touch with him?

If the Waterloo archives are no longer being supported, is there
another repository we can consider?

Thanks!

Doug White

Searching the Uwaterloo.ca website revealed this:

https://uwaterloo.ca/pure-mathematics/people-profiles/leroy-j-dickey

http://www.math.uwaterloo.ca/~ljdickey/

HTH

--
This email has been checked for viruses by AVG.
https://www.avg.com

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• From Doug White@21:1/5 to Kerry Liles on Thu Dec 17 22:09:32 2020
That would be exceedingly generous of Dyalog, especially given that none
of the workspaces have been tested in their APL. Prof. Penfield was
very thorough in his developement of MARTHA, and he had test workspaces
to put all the core functions through their paces and verify their
outputs. I went through the conversion process from an IBM maninframe environment to an STSC mainframe system, and then to STSC PC APL,
APL*PLUS III, as well as MicroAPL on a Mac. The process is never
seamless, especially where graphics are involved.

I did document all the conversion issues I ran into. They are included
in the MARTHA/LLAMA web site documents for anyone attempting a new port,
or wrestling with similar coinversion issues with unrelated workspaces.

Doug White

"Kerry Liles" <kerry.liles@gmail.com> wrote in
news:rrda9m\$g09\$1@dont-email.me:

Doug White wrote:

Prof. Paul Penfield and I have a website of APL material based on his
circuit analysis extensions to APL called MARTHA
(http://www.marthallama.org/). Paul & I aren't getting any younger,
and (as far as I know) visits to the website are now very few & far
between. I was thinking it would be good to find a more permanent
home for the material.

I tried to contact Prof. Lee Dickey at the email address provided at
the APL Archive website he maintained at the University of Waterloo.
After several days, I just got an email delivery failure notice.

Does anyone know if Prof. Dickey is still maintaining the archives?
If so, any idea how best to get in touch with him?

If the Waterloo archives are no longer being supported, is there
another repository we can consider?

Thanks!

Doug White

No idea about Prof. Dickey but perhaps this would be an opportunity
for Dyalog to step up and offer an archival site? Of course, it is
easy for me to suggest other people do things for free, but Dyalog
seems to be the largest company to offer APL related software etc.

--
This email has been checked for viruses by AVG.
https://www.avg.com

--- SoupGate-Win32 v1.05
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• From Guy Larocque@21:1/5 to Doug White on Mon Jan 4 14:22:05 2021
On Thursday, December 17, 2020 at 5:09:36 PM UTC-5, Doug White wrote:
That would be exceedingly generous of Dyalog, especially given that none
of the workspaces have been tested in their APL. Prof. Penfield was
very thorough in his developement of MARTHA, and he had test workspaces
to put all the core functions through their paces and verify their
outputs. I went through the conversion process from an IBM maninframe environment to an STSC mainframe system, and then to STSC PC APL,
APL*PLUS III, as well as MicroAPL on a Mac. The process is never
seamless, especially where graphics are involved.

I did document all the conversion issues I ran into. They are included
in the MARTHA/LLAMA web site documents for anyone attempting a new port,
or wrestling with similar coinversion issues with unrelated workspaces.
Doug White

"Kerry Liles" <kerry...@gmail.com> wrote in news:rrda9m\$g09\$1...@dont-email.me:
Doug White wrote:

Prof. Paul Penfield and I have a website of APL material based on his
circuit analysis extensions to APL called MARTHA
(http://www.marthallama.org/). Paul & I aren't getting any younger,
and (as far as I know) visits to the website are now very few & far
between. I was thinking it would be good to find a more permanent
home for the material.

I tried to contact Prof. Lee Dickey at the email address provided at
the APL Archive website he maintained at the University of Waterloo.
After several days, I just got an email delivery failure notice.

Does anyone know if Prof. Dickey is still maintaining the archives?
If so, any idea how best to get in touch with him?

If the Waterloo archives are no longer being supported, is there
another repository we can consider?

Thanks!

Doug White

No idea about Prof. Dickey but perhaps this would be an opportunity
for Dyalog to step up and offer an archival site? Of course, it is
easy for me to suggest other people do things for free, but Dyalog
seems to be the largest company to offer APL related software etc.
--
This email has been checked for viruses by AVG.
https://www.avg.com

Dear Doug,

Dyalog APL has a github site: https://github.com/Dyalog
You could also try to archive on the sigapl web site: http://www.sigapl.org/

There is a page where you can send an email.

Guy L.

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• From Doug White@21:1/5 to All on Sat Jan 9 22:35:58 2021
Guy Larocque <guy.larocque097@gmail.com> wrote in news:24ca40d3-87cd-4d99-8a8d-bf3deb24e819n@googlegroups.com:
<snip>
Doug White wrote:

Prof. Paul Penfield and I have a website of APL material based on
his circuit analysis extensions to APL called MARTHA
(http://www.marthallama.org/). Paul & I aren't getting any
younger, and (as far as I know) visits to the website are now very
few & far between. I was thinking it would be good to find a more
permanent home for the material.

I tried to contact Prof. Lee Dickey at the email address provided
at the APL Archive website he maintained at the University of
Waterloo. After several days, I just got an email delivery failure
notice.

Does anyone know if Prof. Dickey is still maintaining the
archives? If so, any idea how best to get in touch with him?

If the Waterloo archives are no longer being supported, is there
another repository we can consider?

Thanks!

Doug White
<snip>

Dear Doug,

Dyalog APL has a github site: https://github.com/Dyalog
You could also try to archive on the sigapl web site:
http://www.sigapl.org/

There is a page where you can send an email.

Guy L.

Guy,

Thanks! I'll investigate sigapl for starters.

Doug White

--
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• From Beau Webber@21:1/5 to Doug White on Sun Jan 10 08:19:16 2021
On Thursday, 17 December 2020 at 21:51:37 UTC, Doug White wrote:
Yes, in the case of transistors, they are simulated with a "small
signal" linear model. The transistor parameters are calcualted at a
specific bias condition ("operating point").
Yes commonly it is the "linear over a range of operating parameters" that these transistor parameters are quoted for.
However it is often far simpler and yet more accurate to treat the base-emitter as a forward biased diode, calculate the current for a particular base-emitter current, and then obtain the collector-emitter current by multiplying that by the linearised
gain h_fe for that operating current.

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• From Beau Webber@21:1/5 to All on Sun Jan 10 09:56:46 2021
"calculate the current for a particular base-emitter current" => "calculate the current for a particular base-emitter voltage"

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