What is Java?

The term Java refers to more than just a computer language like C or Pascal. Java encompasses several distinct components:

• A high-level language – Java is an object-oriented language whose source code at a glance looks very similar to C and C++ but is unique in many ways.

• Java bytecode – A compiler transforms the Java language source code to files of binary instructions and data called bytecode that run in the Java Virtual Machine.

• Java Virtual Machine (JVM) – A JVM program takes bytecode as input and interprets the instructions just as if it were a physical processor executing machine code. (We discuss actual hardware implementations of the Java interpreter in Chapter 24.)

Sun Microsystems owns the Java trademark (see the next section on the history of Java) and provides a set of programming tools and class libraries in bundles called Java Software Development Kits (SDKs). The tools include javac, which compiles Java source code into bytecode, and java, the executable program that creates a JVM that executes the bytecode. Sun provides SDKs for Windows, Linux, and Solaris. Other vendors provide SDKs for their own platforms (IBM AIX and Apple Mac OS X, for example). Sun also provides a runtime bundle with just the JVM and a few tools for users who want to run Java programs on their machines but have no intention of creating Java programs. This runtime bundle is called the Java Runtime Environment (JRE).

This book is targeted primarily toward engineers and engineering students of advanced standing (sophomores, seniors and graduate students). Familiarity with a computer language is required; knowledge of basic engineering subjects is useful, but not essential.

The text attempts to place emphasis on numerical methods, not programming. Most engineers are not programmers, but problem solvers. They want to know what methods can be applied to a given problem, what are their strengths and pitfalls and how to implement them. Engineers are not expected to write computer code for basic tasks from scratch; they are more likely to utilize functions and subroutines that have been already written and tested. Thus programming by engineers is largely confined to assembling existing pieces of code into a coherent package that solves the problem at hand.

The “piece” of code is usually a function that implements a specific task. For the user the details of the code are unimportant. What matters is the interface (what goes in and what comes out) and an understanding of the method on which the algorithm is based. Since no numerical algorithm is infallible, the importance of understanding the underlying method cannot be overemphasized; it is, in fact, the rationale behind learning numerical methods.

This book attempts to conform to the views outlined above. Each numerical method is explained in detail and its shortcomings are pointed out. The examples that follow individual topics fall into two categories: hand computations that illustrate the inner workings of the method, and small programs that show how the computer code is utilized in solving a problem.

General Information

Quick Overview

This chapter is not intended to be a comprehensive manual of MATLAB®. Our sole aim is to provide sufficient information to give you a good start. If you are familiar with another computer language, and we assume that you are, it is not difficult to pick up the rest as you go.

MATLAB is a high-level computer language for scientific computing and data visualization built around an interactive programming environment. It is becoming the premiere platform for scientific computing at educational institutions and research establishments. The great advantage of an interactive system is that programs can be tested and debugged quickly, allowing the user to concentrate more on the principles behind the program and less on programming itself. Since there is no need to compile, link and execute after each correction, MATLAB programs can be developed in much shorter time than equivalent FORTRAN or C programs. On the negative side, MATLAB does not produce stand-alone applications—the programs can be run only on computers that have MATLAB installed.

MATLAB has other advantages over mainstream languages that contribute to rapid program development:

• MATLAB contains a large number of functions that access proven numerical libraries, such as LINPACK and EISPACK. This means that many common tasks (e.g., solution of simultaneous equations) can be accomplished with a single function call.

• There is extensive graphics support that allows the results of computations to be plotted with a few statements.

• All numerical objects are treated as double-precision arrays. Thus there is no need to declare data types and carry out type conversions.

General Information

Quick Overview

This chapter is not a comprehensive manual of Python. Its sole aim is to provide sufficient information to give you a good start if you are unfamiliar with Python. If you know another computer language, and presumably you do, it is not difficult to pick up the rest as you go.

Python is an object-oriented language that was developed in late 1980s as a scripting language (the name is derived from the British television show Monty Python's Flying Circus). Although Python is not as well known in engineering circles as some other languages, it has a considerable following in the programming community—in fact, Python is considerably more widespread than Fortran. Python may be viewed as an emerging language, since it is still being developed and refined. In the current state, it is an excellent language for developing engineering applications—it possesses a simple elegance that other programming languages cannot match.

Python programs are not compiled into machine code, but are run by an interpreter. The great advantage of an interpreted language is that programs can be tested and debugged quickly, allowing the user to concentrate more on the principles behind the program and less on programming itself. Since there is no need to compile, link and execute after each correction, Python programs can be developed in a much shorter time than equivalent Fortran or C programs.