Scilab Bag Of Tricks

The Scilab-2.5 IAQ (Infrequently Asked Questions)

Lydia E. van Dijk

Christoph L. Spiel

Copyright © 2000 by L. van Dijk, Ch. L. Spiel

sci-BOT – the Scilab Bag Of Tricks – is a collection of Scilab experience that come from every day use. We warn of common pitfalls, discuss stylistic issues, shed light on unknown spots, and show many different ways of increasing the performance of Scilab functions.

The document is not meant to be comprehensive or even suitable to a particular level of knowledge. Some sections are at the beginners level, some even surprise long-time users.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no invariant sections, with the Front-Cover Texts being "Scilab Bag Of Tricks", and with no Back-Cover Texts. A copy of the license is included in the appendix "GNU Free Documentation License".

Table of Contents

Outline
Other Formats of sci-BOT
Typographic Conventions Used in This Book
Acknowledgments

1. Introduction

2. Common Pitfalls

The Infamous Dot

Vector Construction

Last Newline

Variable Lifetime And Scoping

Local Variable Scoping
Global Variables
Clearing Variables

3. Programming Style

Spacing and Formatting

Intra-Expression Spacing
Line Breaking
Setting Brackets Apart

Indentation

Choice Of Control Structures

while/for
if/select
Strict Block Structure/Premature Return

Size of a Function

4. Unknown Spots

Operator Precedence And Associativity

Numeric Operators
Relational Operators
Logical Operators

Functions Without Arguments or Return Value
Bulletproof Functions
Function Variables
Nested Function Definitions
Functions as Parameters in Function Calls
Functions in tlists
macrovar

Miscellaneous Unknown Spots

Starting scilex
Tuple Assignment
Omitting Parentheses on Function Call

5. Graphics

Function- And Data-Plotting
Graphics Primitives
User Interfaces

6. Performance

High-Level Operations

Vectorized Operations
Avoiding Indexing
Built-In Vector-/Matrix-Functions
Evaluation Of Polynomials

Extending Scilab

Comparison of the Link Overhead
Preparing And Compiling External Subroutines
Pushing It Further

Building an Optimized Scilab

7. Scilab Core

Introduction To pAda

Internal Data Structure

Parameter Stack And Data Stack
Storage of Complex Variables

Writing Native Scilab Functions

Simple Functions
Functionals

Error Handling

Fatal Errors
Warnings
Messages

Interface to Scilab's Core

Query
Access Object
Create Object

8. Further Information

Coping With Scilab

Distribution Size
Bug Hunting

Local Documents

9. Longer Examples

benchmark.sci

listdiff.sci

whatis.sci

Auto-Determination of Precedence and Associativity

assoc.sci
prec.sci
parser.sci

A. GNU Free Documentation License

0. PREAMBLE
1. APPLICABILITY AND DEFINITIONS
2. VERBATIM COPYING
3. COPYING IN QUANTITY
4. MODIFICATIONS
5. COMBINING DOCUMENTS
6. COLLECTIONS OF DOCUMENTS
7. AGGREGATION WITH INDEPENDENT WORKS
8. TRANSLATION
9. TERMINATION
10. FUTURE REVISIONS OF THIS LICENSE

B. GNU General Public License

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1.
2.
3.
4.
5.
6.
7.
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Bibliography

List of Tables
4-1. Arithmetic Operators
4-2. Boolean Operators
6-1. Comparison of various vectorization levels
6-2. Performance comparison of different polynomial evaluation routines
7-1. pAda to Fortran-77 type mappings

List of Figures
6-1. Benchmark results for the mirror functions

		Next
		Preface