[petsc-dev] [petsc-users] new book introducing PETSc for PDEs

[Ed Bueler]

Junchao--

> I was wondering if it is feasible to add your example programs to PETSc
tests so that readers will always be able to run your code.

Thanks for asking.  There was a deliberate idea here, which I want
to explain, and the petsc-dev list is the right spot.  (Sorry if this is
more than you want to know.)

First, the example programs are in a completely public spot:
    https://github.com/bueler/p4pdes
No one needs to own the book to run the codes, for example.  I welcome
corrections/feedback/improvements through the issues interface at that
repo, whether or not connected they are connected to the book text.

In fact, here are things one may observe about the petsc tutorial
src/XX/tutorials/exN.c) examples:

1.  They may or may not point to a clear document(s) which can help a
beginner know how they are designed.
2.  They don't have a uniform style because of different authorship.
3.  They are not ordered by difficulty in any clear way.  (E.g. ex1.c may
not be the best example to start with, and the beginner would not be able
to grep to find "easy" even if they can find some function from the API
that way.)
4.  Their features evolve over time as developers work with the examples as
regression/feature tests.  (See src/snes/tutorials/ex5.c.)

Note that all of these facts are exactly what petsc devs would want!  That
is, the way the set of examples in the petsc tree are structured helps with
fast development by a diverse dev team.

However the same facts make the examples less friendly to those who don't
already know petsc.  Thus my opinion about the book's example codes is that
a single source of stable examples, ordered by difficulty, closely tied to
beginner documentation, of uniform style, and kinda boring to most petsc
devs, is something I can supply and maintain.  So I'll be acting as editor
to preserve the intent and simplicity of the examples.

Does that make sense?

Needless to say, fork my repo all you want!  The MIT license is nice and
permissive.

Ed



On Fri, Oct 30, 2020 at 4:50 PM Junchao Zhang <junchao.zhang at gmail.com>
wrote:

> Prof. Ed Bueler,
>    Congratulations on your book. I am eager to read it.
>    I was wondering if it is feasible to add your example programs to PETSc
> tests so that readers will always be able to run your code.
> --Junchao Zhang
>
>
> On Thu, Oct 29, 2020 at 8:29 PM Ed Bueler <elbueler at alaska.edu> wrote:
>
>> All --
>>
>> SIAM Press just published my new book "PETSc for Partial Differential
>> Equations: Numerical Solutions in C and Python":
>>
>>   https://my.siam.org/Store/Product/viewproduct/?ProductId=32850137
>>
>> The book is available both as a paperback and an e-book with working
>> links.  A SIAM member discount is available, of course.
>>
>> This book is a genuine introduction which does not assume you have used
>> PETSc before, and which should make sense even if your differential
>> equations knowledge is basic.  The prerequisites are a bit of programming
>> in C and a bit of numerical linear algebra, roughly like the main ideas of
>> Trefethen and Bau, but even that is reviewed and summarized.  I've made an
>> effort to introduce discretizations from the beginning, especially finite
>> differences and elements.
>>
>> The book is based on a collection of example programs at
>> https://github.com/bueler/p4pdes.  Most of these codes call PETSc
>> directly through the C API, but the last two chapters have Python codes
>> using UFL and Firedrake.  Nonetheless the book contains ideas, mathematical
>> and computational; it complements, but does not replace, the PETSc User's
>> Manual and the tutorial examples in the PETSc source.  Concepts are
>> explained and illustrated, with sufficient context to facilitate further
>> development. Performance (optimality) and parallel scalability are the
>> primary goals, so preconditioners including multigrid are central threads,
>> and run-time solver options are explored in both the text and the exercises.
>>
>> Here is the place to appreciate the usual PETSc suspects for their
>> comments on drafts, and help in writing this book: Barry, Jed, Matt, Dave,
>> Rich, Lois, Patrick, Mark, Satish, David K., and many others.  Also let me
>> say that SIAM Press has nothing but professionals who are nice to work with
>> too; send them your book idea!
>>
>> Ed
>>
>> --
>> Ed Bueler
>> Dept of Mathematics and Statistics
>> University of Alaska Fairbanks
>> Fairbanks, AK 99775-6660
>> 306C Chapman
>>
>

-- 
Ed Bueler
Dept of Mathematics and Statistics
University of Alaska Fairbanks
Fairbanks, AK 99775-6660
306C Chapman
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