Russian Mathcad Application Server (www.vpu.ru/mas):
field of three years experience

Valery Ochkov http://twt.mpei.ac.ru/ochkov/v_ochkov.htm

Few words about history

Using computers

There is no rose without a thorn

Mathcad documents without Mathcad

Advantages

How much does it cost?

Aims of MAS community

Few words about history

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 dont 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.

Using computers

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.

There is no rose without a thorn

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.

Mathcad documents without Mathcad

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 dont 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.

Advantages

  • 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.

How much does it cost?

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 Russia (http://mas.exponenta.ru) in the framework of a project www.exponenta.ru. This site contains expanded variant of this article and one can discuss it at http://forum.exponenta.ru.

Aims of MAS community

  1. 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.
  2. To improve and upgrade MAS tools, and adapt developed methods of creation network documents (including undocumented) to new Mathcad versions.
  3. 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).
  4. 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.
  5. 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.
  6. 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.
  7. 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