1.1 What Is a Program? And What Is Programming?
3
do? Well, you may write down the recipe in those three languages and send them
over. Now, if you have been able to think correctly when writing down the recipe,
and you have written the explanations according to the rules in each language, each
of your friends will produce the same cake. Your recipe is the “computer program”,
while English, Russian and Chinese represent the “computer languages” with their
own rules of how to write things. The end product, though, is still the same cake.
Note that you may unintentionally introduce errors in your “recipe”. Depending
on the error, this may cause “baking execution” to stop, or perhaps produce the
wrong cake. In your computer program, the errors you introduce are called bugs
(yes, small insects! . . . for historical reasons), and the process of fixing them is called
debugging. When you try to run your program that contains errors, you usually get
warnings or error messages. However, the response you get depends on the error and
the programming language. You may even get no response, but simply the wrong
“cake”. Note that the rules of a programming language have to be followed very
strictly. This differs from languages like English etc., where the meaning might be
understood even with spelling errors and “slang” included.
We Use Python 3.6 in This Book For good reasons, the programming language
used in this book is Python (version 3.6). It is an excellent language for beginners
(and experts!), with a simple and clear syntax. Some of Python’s other strong
properties are 1 : It has a huge and excellent library (i.e., ready-made pieces of
code that you can utilize for certain tasks in your own programs), many global
functions can be placed in only one file, functions are straightforwardly transferred
as arguments to other functions, there is good support for interfacing C, C++ and
Fortran code (i.e., a Python program may use code written in other languages), and
functions explicitly written for scalar input often work fine, without modification,
also with vector input. Another important thing, is that Python is available for free.
It can be downloaded at no cost from the Internet and will run on most platforms.
A Primer on Scientific Programming with Python
Readers who want to expand their scientific programming skills beyond the
introductory level of the present exposition, are encouraged to study A Primer
on Scientific Programming with Python [11]. This comprehensive book is
as suitable for beginners as for professional programmers, and teaches the
art of programming through a huge collection of dedicated examples. This
book is considered the primary reference, and a natural extension, of the
programming matters in the present book. Note, however, that this reference
[11] uses version 2.7 of Python, which means that, in a few cases, instructions
will differ somewhat from what you find in the present book.
1 Some of the words here will be new to you, but relax, they will all be explained as we move
along.
3
do? Well, you may write down the recipe in those three languages and send them
over. Now, if you have been able to think correctly when writing down the recipe,
and you have written the explanations according to the rules in each language, each
of your friends will produce the same cake. Your recipe is the “computer program”,
while English, Russian and Chinese represent the “computer languages” with their
own rules of how to write things. The end product, though, is still the same cake.
Note that you may unintentionally introduce errors in your “recipe”. Depending
on the error, this may cause “baking execution” to stop, or perhaps produce the
wrong cake. In your computer program, the errors you introduce are called bugs
(yes, small insects! . . . for historical reasons), and the process of fixing them is called
debugging. When you try to run your program that contains errors, you usually get
warnings or error messages. However, the response you get depends on the error and
the programming language. You may even get no response, but simply the wrong
“cake”. Note that the rules of a programming language have to be followed very
strictly. This differs from languages like English etc., where the meaning might be
understood even with spelling errors and “slang” included.
We Use Python 3.6 in This Book For good reasons, the programming language
used in this book is Python (version 3.6). It is an excellent language for beginners
(and experts!), with a simple and clear syntax. Some of Python’s other strong
properties are 1 : It has a huge and excellent library (i.e., ready-made pieces of
code that you can utilize for certain tasks in your own programs), many global
functions can be placed in only one file, functions are straightforwardly transferred
as arguments to other functions, there is good support for interfacing C, C++ and
Fortran code (i.e., a Python program may use code written in other languages), and
functions explicitly written for scalar input often work fine, without modification,
also with vector input. Another important thing, is that Python is available for free.
It can be downloaded at no cost from the Internet and will run on most platforms.
A Primer on Scientific Programming with Python
Readers who want to expand their scientific programming skills beyond the
introductory level of the present exposition, are encouraged to study A Primer
on Scientific Programming with Python [11]. This comprehensive book is
as suitable for beginners as for professional programmers, and teaches the
art of programming through a huge collection of dedicated examples. This
book is considered the primary reference, and a natural extension, of the
programming matters in the present book. Note, however, that this reference
[11] uses version 2.7 of Python, which means that, in a few cases, instructions
will differ somewhat from what you find in the present book.
1 Some of the words here will be new to you, but relax, they will all be explained as we move
along.