field of three years experience

There is no rose without a thorn

Mathcad documents without Mathcad

Using computers
for engineering and technical calculations can be conceivably divided into
three historical stages:

- Work with machine codes;
- Using high level languages;
- Work with mathematical packages
(such as Mathcad, Maple, MatLab, Mathematica, MuPAD, Derive and
others).

This list
of packages doesn't contain electronic tables
which remain the most popular tool for accounting and even for technical
calculations. E-tables occupy a position between programming languages and
mathematical programs.

There are
no well-defined borders between listed technologies. For example, we can call
custom functions in Mathcad written in C the code of which contains Assembler
fragments. By the way, the machine codes remain nowadays in programmable
calculators used widely as before in scientific and technical calculations. In
this case we may rather speak about a certain tendency but not about separate
stages of computer tool development. In particular, this tendency results in
sharp time shortening for creation of calculation methods and mathematical
models; removal of a programmer, an additional link between a researcher and a
computer; openness of calculations, when we can see both a result and all
formulas, intermediate data in usual notation.

In
addition, we should note one important aspect of the problem
“researcher--programmer” (“man--computer”). Programming languages don’t support
“amateurish” researcher and demand deep knowledge and skills. To write a
program even for a small calculation often requires lots of time for learning.

Work with
mathematical packages shows another result. For example, we can put off Mathcad
for a long time, but basic skills remain and if necessary, we can solve a
problem quickly without help of a programmer.

We can mark
out three historical stages in a way of using computers to solve scientific and
engineering problems.

- Batch, when one computer works
with a group of users and their problems were entered on punch cards
- Local, work with personal
computers
- Network, when we have returned
in point of fact to batch stage but on another, higher level. Source data,
results are transferred not on the paper but on the Internet; the
calculations can be done simultaneously, if need be (clustered,
distributed calculation etc).

Using
Mathcad makes process of setting and solving a problem ten times quicker.
Change from machine codes to high level programming languages (Fortran, Pascal, BASIC, etc) made the same burst.

Substituting
Mathcad environment for work with these languages we remove a superfluous link,
a programmer.

Even if a
user knows programming languages, it is worthy of use Mathcad at least to set
mathematical model and check it for errors. The group of developers under the
guideline of the author created and successfully promotes certified package
WaterSteamPro® (www.wsp.ru) for calculation of
heat-transfer properties of heat carrier at power stations, municipal heat
supply systems. Final version was written and compiled on Visual C++ but it
could not be possible without previous analysis of the formulas and algorithms
in Mathcad with its handy visualization tools.

As a rule,
the main disadvantage of mathematical packages was impossibility to generate
executed files. That prevents such progressive phenomenon as dividing the
people working with computer into users and developers. Those who working with
mathematical packages usually keep “subsistence farming” – develop methods only
for private use or for colleagues' circle
knowing Mathcad. One could give his programs only to those who had installed
Mathcad. Such user would not buy the program but will try to reconstruct it. Of
course, I mean small calculation programs which require time for developing and
debugging comparable with that for searching for finished program, installation
and studying a new package.

A Mathcad
file could be given or sold only if a user had installed required version of
Mathcad package and knows its basics.

I should
note here that installation of a package may result in upgrade of operating
system and a computer itself.

Mathsoft
Company had begun to work with this problem. Eighth version of Mathcad included
free program Mathcad Explorer which allows Mathcad files to be opened and make
calculations without changes in source code. Moreover, Mathcad Explorer could
be free downloaded from the Internet.

That results
in intensive development of publication tools in local networks (corporative
and especially in university) and in the Internet. The main user of
mathematical packages is education sphere, where the result is not the most
important but the way to result, study of methods. Particularly, version
Mathcad 2001i, “i” means interactive, was aimed to
this.

As we can
see, both variants don’t improve situation completely. Solution has appeared
under the name Mathcad Application Server (MAS). MAS
technology allows running Mathcad documents on the servers and calling it
distantly on the Internet.

- We have not to buy and install
required version of Mathcad, check mcd-files for viruses and run them. We
only connect computers to the Internet, call MAS server using Internet
Explorer (version 5.5 and higher) or others. This looks like work with
Mathcad document. Calculation method and intermediate data can be visible
or hidden partially or completely in case of selling only the result of a
calculation, not a method.
- New methods of calculation
became available for all the users of the Internet instantly. We should
only give corresponding addresses to users.
- Any error, misprint,
imperfection and assumption in a calculation noted by an author or users
can be corrected easily. We can upgrade and extend the calculation, too.
- The MAS technology does not
exclude tradition capability to download Mathcad documents from a server
for its upgrading or extending. We only must make a corresponding
reference to the FTP server. There are two ways of using mcd-files. We can
transfer them only for calculations on the working station with installed
Mathcad and lock calculations with passwords. Another way is to give them
freely or sell for work without limitations.
- The MAS technology allows us to
cut down expenses for software. Mathcad package is needed now only for
those who develop documents. Others can use corporation or exterior
server.

Mathcad
Application Server package is not cheap but educational organizations have 50%
discount. The question can arise: to buy the same package copies as the number
of working stations or to buy one or two copies for the developer and editor of
worksheets and use Mathcad Application Server for others. Besides, it is possible
to store calculations on an exterior server and pay for the rent.

The author
server has allocated more than 10 000 different webcalculations
for last thee years (see >>>>>>>).
At the same time, the detailed guides were developed how to make a worksheet
well-suited for Application Server use.

The
following problems are opened in MAS-documents:

- To develop “live” plots, tables
and formulas from the reference books and manuals (see >>>>>>>);
- To develop the gallery of
“live” or pseudoanimated illustrations for
numerical mathematics algorithms (see example >>>>>>>);
illustration of analytical methods;
- To create network documents for
tests (see example >>>>>>>)
- To create “live” calculation
methods for practical orientation and many others.

The set of
Web controls for changing data in a document opened on the network is not wide
but it is possible to avoid many of its limitations. The following problems
have been solved while working and testing the system:

- Access to a calculation with a
password;
- Changing languages in a
document;
- Addition changing figures and
formula sets to a calculation;
- Blocking some interface
elements;
- Inserting large arrays with
saving variants, etc.

Some of calculations
were certified. First, some calculations have a “suitability seal” with the
reference to a letter from an authoritative organization in a problem.
Second, a site of an authoritative organization make
references to the calculations (for example, www.iapws.org).

Although,
some problems still exist. The certified calculations are still opened for
editing and therefore for damage accidental or intentional.

In summer
2006 the second Mathcad server was appeared in

- To create new interesting
and/or useful calculation methods; search new branches for MAS technology
in educational, engineering and technical practices. It is urgent to
improve early calculation documents having been developed without 3 years
experience.
- To improve and upgrade MAS
tools, and adapt developed methods of creation network documents
(including undocumented) to new Mathcad versions.
- To make Windows applications
that we can use in Mathcad offline accessible in MAS. Now such data
exchange is blocked. This problem is rather political than technical: for
example, if a user installed Microsoft Excel it is licensed for individual
use (if it was done at all).
- Paralleling MAS calculations. A
problem processed on MAS can be divided and handled in separate computers.
This will speed up calculations, make possible to solve special problem class
requiring many resources.
- To improve reliability of
servers by duplicating calculations on several servers. If one of them is
overloaded or buzzed a network calculation can be transferred to spare
server.
- Certification of calculations
accessed for general use. We might think about certified content managers
working at the interfaces between informatics and another scientific or
engineering branch who have direct access to servers.
- To make paid access to some
worksheets and develop rows of certified calculations with commercial
orientation.

Others
books and articles of Valery Ochkov http://twt.mpei.ac.ru/ochkov/work2_eng.htm