DOCSLIB.ORG

An Introduction to Programming in Simula

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
An Introduction to Programming in Simula An Introduction to Programming in Simula Rob Pooley This document, including all parts below hyperlinked directly to it, is copyright Rob Pooley ([email protected]). You are free to use it for your own non-commercial purposes, but may not copy it or reproduce all or part of it without including this paragraph. If you wish to use it for gain in any manner, you should contact Rob Pooley for terms appropriate to that use. Teachers in publicly funded schools, universities and colleges are free to use it in their normal teaching. Anyone, including vendors of commercial products, may include links to it in any documentation they distribute, so long as the link is to this page, not any sub-part. This is an .pdf version of the book originally published by Blackwell Scientific Publications. The copyright of that book also belongs to Rob Pooley. REMARK: This document is reassembled from the HTML version found on the web: https://web.archive.org/web/20040919031218/http://www.macs.hw.ac.uk/~rjp/bookhtml/ Oslo 20. March 2018 Øystein Myhre Andersen Table of Contents Chapter 1 - Begin at the beginning Basics Chapter 2 - And end at the end Syntax and semantics of basic elements Chapter 3 - Type cast actors Basic arithmetic and other simple types Chapter 4 - If only Conditional statements Chapter 5 - Would you mind repeating that? Texts and while loops Chapter 6 - Correct Procedures Building blocks Chapter 7 - File FOR future reference Simple input and output using InFile, OutFile and PrintFile Chapter 8 - Item by Item Item oriented reading and writing and for loops Chapter 9 - Classes as Records Chapter 10 - Make me a list Lists 1 - Arrays and simple linked lists Reference comparison Chapter 11 - Like parent like child Sub-classes and complex Boolean expressions Chapter 12 - A Language with Character Character handling, switches and jumps Chapter 13 - Let Us See what We Can See Inspection and Remote Accessing Chapter 14 - Side by Side Coroutines Chapter 15 - File For Immediate Use Direct and Byte Files Chapter 16 - With All My Worldly Goods... Prefixed Blocks And Separate Compilation Chapter 17 - Add To The List More Complex List Structures - SimSet Chapter 18 - Virtually Anything Is Possible A More Formal Definition Of Scope; Virtual, Hidden and Protected Chapter 19 - Class Simulation SIMULA and simulation Chapter 20 - Tying Up Loose Ends The Complete Environment and Where to Go From Here Appendix A - Arithmetic expressions Appendix B - Arithmetic types Appendix C - Alternative number bases Appendix D - Conditional expressions Chapter 1 begin at the beginning...... What is a computer program? A computer program (program is always spelt in the American way) is a series of instructions which contains all the information necessary for a computer to perform some task. It is similar to a knitting pattern, a recipe or a musical score. Like all of these it uses a special shorthand, known in this case as a programming language. This book describes how to write and understand programs written in the language SIMULA. The definition used is the 1985 SIMULA Standard, which extends and clarifies the language previously known as SIMULA 67. The 67 stood for 1967, the year in which this earlier version was first defined. These should not be confused with the older language known as SIMULA 1, which is an ancestor of SIMULA 67 and thus of today's SIMULA. A few old references to SIMULA (notably a 1966 article in CACM) will mean SIMULA 1. More often SIMULA 67 is intended. Many implementations of SIMULA will not yet have all the features given in the 1984 standard, although they will probably have more than those defined in 1967. Wherever sensible this book tries to warn its readers of features which may not be universally available. In addition, it is usually a good idea to check the documentation for the particular SIMULA system to be used, in case it has any peculiarities of its own. SIMULA is highly standardised, but differences may still be found. You may already be familiar with other programming languages such as Fortran, Basic or Pascal. Even so you will find this introduction essential, since SIMULA views the world rather differently in some ways. In particular SIMULA expects you to organise or structure your program carefully. It also allows you to describe actions as if they were happening simultaneously or in parallel. If the next paragraph seems confusing, read it now and see how much you can understand, then come back after each chapter until it makes complete sense. Do the same for any other parts of this book which are not clear at first reading. Remember that in learning a new computer language you are trying to take in many concepts which only make sense together, so that often several re- readings of what will later seem obvious points are necessary. A SIMULA program is made up of sequences of instructions known as blocks, which act independently to varying degrees, but which are combined to produce the desired overall effect. The simplest programs contain only one block, known as the program block. All other blocks follow the same basic rules, so let us have a look at the single block program, example 1.1. Example 1.1: A simple example begin integer Int1; comment The first SIMULA program written for this book; Int1:=3; OutInt(Int1,4); OutImage end This is not the simplest possible program. We could have written begin end and had a complete program block. This tells us the first rule about all blocks. A block always begins with the word begin and ends with the word end. beginand end are called "keywords", since they are reserved for special purposes and may not be used for anything else. A note on letters and "cases". Although the programs shown in this book use bothcapital letters, which are known to computer programmers as "upper case" characters, and small, "lower case", letters. You are free to use whichever case you prefer. A SIMULA program is interpreted as if all its letters, which are not enclosed in double quotes, were first converted to upper case. You can even write BegIN or eNd. The right ingredients So we have to put begin and end. What about the text in between? This is made up of instructions to the SIMULA system, which are of two types; DECLARATIONS and STATEMENTS. There are also pieces of the text which are ignored by the SIMULA system and which simply help any human who reads the program to follow what is happening. These are called comments. Declarations In example 1.1, the first instruction after the word begin is a declaration: integer Int1; Declarations in a block show how much of the computer's memory is going to be needed by that block. They also show into how many sections it is to be divided , how big each is to be and to what sort of use each will be put. Each of these sections is given a name, by which the program will refer to it. The program block in example 1.1 has only one declaration. It starts with the "type" keyword integer, followed by a name or "identifier", Int1. The type (integer in this example) says what the section of memory will be used for. In example 1.1 it will be used to hold a whole number, which is called an integer in SIMULA. Once a section of memory has been given its type in this way, it may not be used to hold something of a different type. Since this location will hold an integer its required size will also be known to the SIMULA system. All items of the same type require the same amount of space in memory to hold them. The identifier Int1 is now the name of the space reserved in this way. We may sometimes refer to the value held in this space as Int1 also. This is a useful shorthand, especially when we are not aware what the current contents are. If we want to use more locations, we can declare them in the same way, being careful to give the correct type to each. Thus we might write begin integer Int1; real Real1; etc. Which gives us a location of type real and called Real1, which we can use in this block. The possible types and their uses are explained more fully in chapter 3. If we want to have more than one location which can hold a whole number, then we can declare a second integer, with a different identifier. We might do this by writing begin integer Int1; integer Count; etc. or, alternatively, by writing begin integer Int1, Count; etc. which many people find neater. This style is called a declaration list, with a series of identifiers of locations with the same type separated by commas. Comments The next line is a comment. It begins with the keyword comment, is followed by some text and ends in a semi-colon. comment The first SIMULA program written for this book; It has no effect on what the program does, but it contains some information on what the program is or does. In example 1.1 it tells us which version of the program we are looking at. This is often very useful. As well as forming lines on their own, comments can also be used in certain places within instructions or combined on the same line as them. This will be shown in the next chapter. When you are writing programs in independent sections, as we will be, you may not look back at a "working" component for some time.
Load more

Recommended publications
  • C++ Programming: Program Design Including Data Structures, Fifth Edition
    C++ Programming: From Problem Analysis to Program Design, Fifth Edition Chapter 5: Control Structures II (Repetition) Objectives In this chapter, you will: • Learn about repetition (looping) control structures • Explore how to construct and use count- controlled, sentinel-controlled, flag- controlled, and EOF-controlled repetition structures • Examine break and continue statements • Discover how to form and use nested control structures C++ Programming: From Problem Analysis to Program Design, Fifth Edition 2 Objectives (cont'd.) • Learn how to avoid bugs by avoiding patches • Learn how to debug loops C++ Programming: From Problem Analysis to Program Design, Fifth Edition 3 Why Is Repetition Needed? • Repetition allows you to efficiently use variables • Can input, add, and average multiple numbers using a limited number of variables • For example, to add five numbers: – Declare a variable for each number, input the numbers and add the variables together – Create a loop that reads a number into a variable and adds it to a variable that contains the sum of the numbers C++ Programming: From Problem Analysis to Program Design, Fifth Edition 4 while Looping (Repetition) Structure • The general form of the while statement is: while is a reserved word • Statement can be simple or compound • Expression acts as a decision maker and is usually a logical expression • Statement is called the body of the loop • The parentheses are part of the syntax C++ Programming: From Problem Analysis to Program Design, Fifth Edition 5 while Looping (Repetition)
    [Show full text]
  • Compiler Construction Assignment 3 – Spring 2018
    Compiler Construction Assignment 3 { Spring 2018 Robert van Engelen µc for the JVM µc (micro-C) is a small C-inspired programming language. In this assignment we will implement a compiler in C++ for µc. The compiler compiles µc programs to java class files for execution with the Java virtual machine. To implement the compiler, we can reuse the same concepts in the code-generation parts that were done in programming assignment 1 and reuse parts of the lexical analyzer you implemented in programming assignment 2. We will implement a new parser based on Yacc/Bison. This new parser utilizes translation schemes defined in Yacc grammars to emit Java bytecode. In the next programming assignment (the last assignment following this assignment) we will further extend the capabilities of our µc compiler by adding static semantics such as data types, apply type checking, and implement scoping rules for functions and blocks. Download Download the Pr3.zip file from http://www.cs.fsu.edu/~engelen/courses/COP5621/Pr3.zip. After unzipping you will get the following files Makefile A makefile bytecode.c The bytecode emitter (same as Pr1) bytecode.h The bytecode definitions (same as Pr1) error.c Error reporter global.h Global definitions init.c Symbol table initialization javaclass.c Java class file operations (same as Pr1) javaclass.h Java class file definitions (same as Pr1) mycc.l *) Lex specification mycc.y *) Yacc specification and main program symbol.c *) Symbol table operations test#.uc A number of µc test programs The files marked ∗) are incomplete. For this assignment you are required to complete these files.
    [Show full text]
  • PDF Python 3
    Python for Everybody Exploring Data Using Python 3 Charles R. Severance 5.7. LOOP PATTERNS 61 In Python terms, the variable friends is a list1 of three strings and the for loop goes through the list and executes the body once for each of the three strings in the list resulting in this output: Happy New Year: Joseph Happy New Year: Glenn Happy New Year: Sally Done! Translating this for loop to English is not as direct as the while, but if you think of friends as a set, it goes like this: “Run the statements in the body of the for loop once for each friend in the set named friends.” Looking at the for loop, for and in are reserved Python keywords, and friend and friends are variables. for friend in friends: print('Happy New Year:', friend) In particular, friend is the iteration variable for the for loop. The variable friend changes for each iteration of the loop and controls when the for loop completes. The iteration variable steps successively through the three strings stored in the friends variable. 5.7 Loop patterns Often we use a for or while loop to go through a list of items or the contents of a file and we are looking for something such as the largest or smallest value of the data we scan through. These loops are generally constructed by: • Initializing one or more variables before the loop starts • Performing some computation on each item in the loop body, possibly chang- ing the variables in the body of the loop • Looking at the resulting variables when the loop completes We will use a list of numbers to demonstrate the concepts and construction of these loop patterns.
    [Show full text]
  • Verifiable Semantic Difference Languages
    Verifiable Semantic Difference Languages Thibaut Girka David Mentré Yann Régis-Gianas Mitsubishi Electric R&D Centre Mitsubishi Electric R&D Centre Univ Paris Diderot, Sorbonne Paris Europe Europe Cité, IRIF/PPS, UMR 8243 CNRS, PiR2, Rennes, France Rennes, France INRIA Paris-Rocquencourt Paris, France ABSTRACT 1 INTRODUCTION Program differences are usually represented as textual differences Let x be a strictly positive natural number. Consider the following on source code with no regard to its syntax or its semantics. In two (almost identical) imperative programs: this paper, we introduce semantic-aware difference languages. A difference denotes a relation between program reduction traces. A s = 0 ; 1 s = 0 ; 1 difference language for the toy imperative programming language d = x ; 2 d = x − 1 ; 2 while (d>0) { 3 while (d>0) { 3 Imp is given as an illustration. i f (x%d== 0) 4 i f (x%d== 0) 4 To certify software evolutions, we want to mechanically verify s = s + d ; 5 s = s + d ; 5 − − that a difference correctly relates two given programs. Product pro- d = d 1 ; 6 d = d 1 ; 6 } 7 } 7 grams and correlating programs are effective proof techniques for s = s − x 8 8 relational reasoning. A product program simulates, in the same programming language as the compared programs, a well-chosen The program P1 (on the left) stores in s the sum of the proper interleaving of their executions to highlight a specific relation be- divisors of the integer x. To that end, it iterates over the integers tween their reduction traces. While this approach enables the use from x to 1 using the variable d and accumulates in the variable s of readily-available static analysis tools on the product program, it the values of d that divide x.
    [Show full text]
  • 7. Control Flow First?
    Copyright (C) R.A. van Engelen, FSU Department of Computer Science, 2000-2004 Ordering Program Execution: What is Done 7. Control Flow First? Overview Categories for specifying ordering in programming languages: Expressions 1. Sequencing: the execution of statements and evaluation of Evaluation order expressions is usually in the order in which they appear in a Assignments program text Structured and unstructured flow constructs 2. Selection (or alternation): a run-time condition determines the Goto's choice among two or more statements or expressions Sequencing 3. Iteration: a statement is repeated a number of times or until a Selection run-time condition is met Iteration and iterators 4. Procedural abstraction: subroutines encapsulate collections of Recursion statements and subroutine calls can be treated as single Nondeterminacy statements 5. Recursion: subroutines which call themselves directly or indirectly to solve a problem, where the problem is typically defined in terms of simpler versions of itself 6. Concurrency: two or more program fragments executed in parallel, either on separate processors or interleaved on a single processor Note: Study Chapter 6 of the textbook except Section 7. Nondeterminacy: the execution order among alternative 6.6.2. constructs is deliberately left unspecified, indicating that any alternative will lead to a correct result Expression Syntax Expression Evaluation Ordering: Precedence An expression consists of and Associativity An atomic object, e.g. number or variable The use of infix, prefix, and postfix notation leads to ambiguity An operator applied to a collection of operands (or as to what is an operand of what arguments) which are expressions Fortran example: a+b*c**d**e/f Common syntactic forms for operators: The choice among alternative evaluation orders depends on Function call notation, e.g.
    [Show full text]
  • Repetition Structures
    24785_CH06_BRONSON.qrk 11/10/04 9:05 M Page 301 Repetition Structures 6.1 Introduction Goals 6.2 Do While Loops 6.3 Interactive Do While Loops 6.4 For/Next Loops 6.5 Nested Loops 6.6 Exit-Controlled Loops 6.7 Focus on Program Design and Implementation: After-the- Fact Data Validation and Creating Keyboard Shortcuts 6.8 Knowing About: Programming Costs 6.9 Common Programming Errors and Problems 6.10 Chapter Review 24785_CH06_BRONSON.qrk 11/10/04 9:05 M Page 302 302 | Chapter 6: Repetition Structures The applications examined so far have illustrated the programming concepts involved in input, output, assignment, and selection capabilities. By this time you should have gained enough experience to be comfortable with these concepts and the mechanics of implementing them using Visual Basic. However, many problems require a repetition capability, in which the same calculation or sequence of instructions is repeated, over and over, using different sets of data. Examples of such repetition include continual checking of user data entries until an acceptable entry, such as a valid password, is made; counting and accumulating running totals; and recurring acceptance of input data and recalculation of output values that only stop upon entry of a designated value. This chapter explores the different methods that programmers use to construct repeating sections of code and how they can be implemented in Visual Basic. A repeated procedural section of code is commonly called a loop, because after the last statement in the code is executed, the program branches, or loops back to the first statement and starts another repetition.
    [Show full text]
  • 6Up with Notes
    Notes CSCE150A Computer Science & Engineering 150A Problem Solving Using Computers Lecture 05 - Loops Stephen Scott (Adapted from Christopher M. Bourke) Fall 2009 1 / 1 [email protected] Chapter 5 CSCE150A 5.1 Repetition in Programs 5.2 Counting Loops and the While Statement 5.3 Computing a Sum or a Product in a Loop 5.4 The for Statement 5.5 Conditional Loops 5.6 Loop Design 5.7 Nested Loops 5.8 Do While Statement and Flag-Controlled Loops 5.10 How to Debug and Test 5.11 Common Programming Errors 2 / 1 Repetition in Programs CSCE150A Just as the ability to make decisions (if-else selection statements) is an important programming tool, so too is the ability to specify the repetition of a group of operations. When solving a general problem, it is sometimes helpful to write a solution to a specific case. Once this is done, ask yourself: Were there any steps that I repeated? If so, which ones? Do I know how many times I will have to repeat the steps? If not, how did I know how long to keep repeating the steps? 3 / 1 Notes Counting Loops CSCE150A A counter-controlled loop (or counting loop) is a loop whose repetition is managed by a loop control variable whose value represents a count. Also called a while loop. 1 Set counter to an initial value of 0 2 while counter < someF inalV alue do 3 Block of program code 4 Increase counter by 1 5 end Algorithm 1: Counter-Controlled Loop 4 / 1 The C While Loop CSCE150A This while loop computes and displays the gross pay for seven employees.
    [Show full text]
  • A Short Introduction to Ocaml
    Ecole´ Polytechnique INF549 A Short Introduction to OCaml Jean-Christophe Filli^atre September 11, 2018 Jean-Christophe Filli^atre A Short Introduction to OCaml INF549 1 / 102 overview lecture Jean-Christophe Filli^atre labs St´ephaneLengrand Monday 17 and Tuesday 18, 9h{12h web site for this course http://www.enseignement.polytechnique.fr/profs/ informatique/Jean-Christophe.Filliatre/INF549/ questions ) [email protected] Jean-Christophe Filli^atre A Short Introduction to OCaml INF549 2 / 102 OCaml OCaml is a general-purpose, strongly typed programming language successor of Caml Light (itself successor of Caml), part of the ML family (SML, F#, etc.) designed and implemented at Inria Rocquencourt by Xavier Leroy and others Some applications: symbolic computation and languages (IBM, Intel, Dassault Syst`emes),static analysis (Microsoft, ENS), file synchronization (Unison), peer-to-peer (MLDonkey), finance (LexiFi, Jane Street Capital), teaching Jean-Christophe Filli^atre A Short Introduction to OCaml INF549 3 / 102 first steps with OCaml Jean-Christophe Filli^atre A Short Introduction to OCaml INF549 4 / 102 the first program hello.ml print_string "hello world!\n" compiling % ocamlopt -o hello hello.ml executing % ./hello hello world! Jean-Christophe Filli^atre A Short Introduction to OCaml INF549 5 / 102 the first program hello.ml print_string "hello world!\n" compiling % ocamlopt -o hello hello.ml executing % ./hello hello world! Jean-Christophe Filli^atre A Short Introduction to OCaml INF549 5 / 102 the first program hello.ml
    [Show full text]
  • Openmp for C Or Fortran
    OpenMP for C or Fortran Summer Seminar ISC5939 .......... John Burkardt Department of Scientific Computing Florida State University http://people.sc.fsu.edu/∼jburkardt/presentations/. openmp 2012 fsu.pdf 31 July/02 August 2012 1 / 144 Shared Memory Programming with OpenMP 1 INTRODUCTION 2 Directives 3 Loops 4 Critical Regions and Reductions 5 Data Conflicts and Data Dependence 6 Environment Variables and Functions 7 Compiling, Linking, Running 8 Parallel Control Structures 9 Data Classification 10 Examples 11 Conclusion 2 / 144 INTRO: OLD LANGUAGES=>OpenMP=>New Hardware OpenMP is a bridge between yesterday's programming languages and tomorrow's multicore chips (4 cores when I first gave this talk, 48 cores now here at FSU!) 3 / 144 INTRO: Hardware Options OpenMP runs a user program on shared memory systems: a single core chip (older PC's, sequential execution) a multicore chip (such as your laptop?) multiple single core chips in a NUMA system multiple multicore chips in a NUMA system (SGI system) multiple multicore chips using other schemes (Intel's Cluster OpenMP) The computer lab DSL400B uses 2 core machines; the DSL152 lab has 8 core machines. OpenMP, which you can think of as running on one tightly-coupled chip, can also be combined with MPI, which runs on multiple, loosely-networked chips... but that's another talk! 4 / 144 INTRO: OpenMP Limitations OpenMP is limited by the shared memory hardware. An OpenMP program can only handle problems that fit on the chip or the coupled chips, over which memory can be shared. If an MPI program running on 5 chips needs more memory, it can easily be run on 100 chips, getting 20 times more memory.
    [Show full text]
  • Chapter 7 Loops
    PROG0101 Fundamentals of Programming PROG0101 FUNDAMENTALS OF PROGRAMMING Chapter 7 Loops 1 PROG0101 Fundamentals of Programming Loops Topics • Loops • Condition Tested Loops • Counted Loops • Endless Loops • FOR Loop • WHILE Loop • DO-WHILE Loop 2 PROG0101 Fundamentals of Programming Loops Loops • A loop is a sequence of instructions that is continually repeated until a certain condition is reached. • Loops allow for the same statement to be executed a number of times in succession. 3 PROG0101 Fundamentals of Programming Loops Loops Pseudocode: Flowchart: Loop False Do Something Condition Until Condition True Do something 4 PROG0101 Fundamentals of Programming Loops Loops • There are three types which are common to most programming languages: – Condition Tested Loops – Counted Loops – Endless Loops 5 PROG0101 Fundamentals of Programming Loops Condition Tested Loops • A condition tested loop is one which repeats a set of instructions until a certain condition is reached. • The test can be performed at the start of the loop (before any of the instructions are executed), during the loop, or at the end of the loop. • Usually, the condition will be testing the result of executing the statements that are inside the loop. 6 PROG0101 Fundamentals of Programming Loops Counted Loops • A counted loop is one which allows the programmer to instruct the computer to perform a set of instructions x times, where x is usually an integer value, but some programming languages offer other data types. • One could argue that the counted loop is just a condition tested loop which updates a counter and exits once a given value is reached. 7 PROG0101 Fundamentals of Programming Loops Counted Loops • The only time to use a count loop is when the program can determine ahead of time how many times the loop will repeat.
    [Show full text]
  • Coral: an Ultra-Simple Language for Learning to Program
    Paper ID #27084 Coral: An Ultra-Simple Language For Learning to Program Dr. Alex Daniel Edgcomb, Zybooks Alex Edgcomb is Sr. Software Engineer at zyBooks.com, a startup spun-off from UC Riverside that develops interactive, web-native learning materials for STEM courses. Alex is also a research specialist at UC Riverside, studying the efficacy of web-native content and digital education. Prof. Frank Vahid, University of California, Riverside Frank Vahid is a Professor of Computer Science and Engineering at the Univ. of California, Riverside. His research interests include embedded systems design, and engineering education. He is a co-founder of zyBooks.com. Prof. Roman Lysecky, University of Arizona Roman Lysecky is a Professor of Electrical and Computer Engineering at the University of Arizona. He received his Ph.D. in Computer Science from the University of California, Riverside in 2005. His research interests include embedded systems, runtime optimization, non-intrusive system observation methods, data-adaptable systems, and embedded system security. He has recently coauthored multiple textbooks, published by zyBooks, that utilize a web-native, interactive, and animated approach, which has shown notable increases in student learning and course grades. c American Society for Engineering Education, 2019 Coral: An Ultra-Simple Language For Learning to Program Abstract University-level introductory programming courses, sometimes called CS0 (non-majors) and CS1 (majors), often teach an industry language, such as Java, C++, and Python. However, such languages were designed for professionals, not learners. Some CS0 courses teach a graphical programming language, such as Scratch, Snap, and Alice. However, many instructors want a more serious feel for college students that also leads more directly into an industry language.
    [Show full text]
  • Numerical Models Show Coral Reefs Can Be Self -Seeding
    MARINE ECOLOGY PROGRESS SERIES Vol. 74: 1-11, 1991 Published July 18 Mar. Ecol. Prog. Ser. Numerical models show coral reefs can be self -seeding ' Victorian Institute of Marine Sciences, 14 Parliament Place, Melbourne, Victoria 3002, Australia Australian Institute of Marine Science, PMB No. 3, Townsville MC, Queensland 4810, Australia ABSTRACT: Numerical models are used to simulate 3-dimensional circulation and dispersal of material, such as larvae of marine organisms, on Davies Reef in the central section of Australia's Great Barner Reef. Residence times on and around this reef are determined for well-mixed material and for material which resides at the surface, sea bed and at mid-depth. Results indcate order-of-magnitude differences in the residence times of material at different levels in the water column. They confirm prevlous 2- dimensional modelling which indicated that residence times are often comparable to the duration of the planktonic larval life of many coral reef species. Results reveal a potential for the ma~ntenanceof local populations of vaiious coral reef organisms by self-seeding, and allow reinterpretation of the connected- ness of the coral reef ecosystem. INTRODUCTION persal of particles on reefs. They can be summarised as follows. Hydrodynamic experiments of limited duration Circulation around the reefs is typified by a complex (Ludington 1981, Wolanski & Pickard 1983, Andrews et pattern of phase eddies (Black & Gay 1987a, 1990a). al. 1984) have suggested that flushing times on indi- These eddies and other components of the currents vidual reefs of Australia's Great Barrier Reef (GBR) are interact with the reef bathymetry to create a high level relatively short in comparison with the larval life of of horizontal mixing on and around the reefs (Black many different coral reef species (Yamaguchi 1973, 1988).
    [Show full text]