Scientific Programming in Fortran 2003
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Writing Fast Fortran Routines for Python
Writing fast Fortran routines for Python Table of contents Table of contents ............................................................................................................................ 1 Overview ......................................................................................................................................... 2 Installation ...................................................................................................................................... 2 Basic Fortran programming ............................................................................................................ 3 A Fortran case study ....................................................................................................................... 8 Maximizing computational efficiency in Fortran code ................................................................. 12 Multiple functions in each Fortran file ......................................................................................... 14 Compiling and debugging ............................................................................................................ 15 Preparing code for f2py ................................................................................................................ 16 Running f2py ................................................................................................................................. 17 Help with f2py .............................................................................................................................. -
Scope in Fortran 90
Scope in Fortran 90 The scope of objects (variables, named constants, subprograms) within a program is the portion of the program in which the object is visible (can be use and, if it is a variable, modified). It is important to understand the scope of objects not only so that we know where to define an object we wish to use, but also what portion of a program unit is effected when, for example, a variable is changed, and, what errors might occur when using identifiers declared in other program sections. Objects declared in a program unit (a main program section, module, or external subprogram) are visible throughout that program unit, including any internal subprograms it hosts. Such objects are said to be global. Objects are not visible between program units. This is illustrated in Figure 1. Figure 1: The figure shows three program units. Main program unit Main is a host to the internal function F1. The module program unit Mod is a host to internal function F2. The external subroutine Sub hosts internal function F3. Objects declared inside a program unit are global; they are visible anywhere in the program unit including in any internal subprograms that it hosts. Objects in one program unit are not visible in another program unit, for example variable X and function F3 are not visible to the module program unit Mod. Objects in the module Mod can be imported to the main program section via the USE statement, see later in this section. Data declared in an internal subprogram is only visible to that subprogram; i.e. -
Inf 212 Analysis of Prog. Langs Elements of Imperative Programming Style
INF 212 ANALYSIS OF PROG. LANGS ELEMENTS OF IMPERATIVE PROGRAMMING STYLE Instructors: Kaj Dreef Copyright © Instructors. Objectives Level up on things that you may already know… ! Machine model of imperative programs ! Structured vs. unstructured control flow ! Assignment ! Variables and names ! Lexical scope and blocks ! Expressions and statements …so to understand existing languages better Imperative Programming 3 Oldest and most popular paradigm ! Fortran, Algol, C, Java … Mirrors computer architecture ! In a von Neumann machine, memory holds instructions and data Control-flow statements ! Conditional and unconditional (GO TO) branches, loops Key operation: assignment ! Side effect: updating state (i.e., memory) of the machine Simplified Machine Model 4 Registers Code Data Stack Program counter Environment Heap pointer Memory Management 5 Registers, Code segment, Program counter ! Ignore registers (for our purposes) and details of instruction set Data segment ! Stack contains data related to block entry/exit ! Heap contains data of varying lifetime ! Environment pointer points to current stack position ■ Block entry: add new activation record to stack ■ Block exit: remove most recent activation record Control Flow 6 Control flow in imperative languages is most often designed to be sequential ! Instructions executed in order they are written ! Some also support concurrent execution (Java) But… Goto in C # include <stdio.h> int main(){ float num,average,sum; int i,n; printf("Maximum no. of inputs: "); scanf("%d",&n); for(i=1;i<=n;++i){ -
Jalopy User's Guide V. 1.9.4
Jalopy - User’s Guide v. 1.9.4 Jalopy - User’s Guide v. 1.9.4 Copyright © 2003-2010 TRIEMAX Software Contents Acknowledgments . vii Introduction . ix PART I Core . 1 CHAPTER 1 Installation . 3 1.1 System requirements . 3 1.2 Prerequisites . 3 1.3 Wizard Installation . 4 1.3.1 Welcome . 4 1.3.2 License Agreement . 5 1.3.3 Installation Features . 5 1.3.4 Online Help System (optional) . 8 1.3.5 Settings Import (optional) . 9 1.3.6 Configure plug-in Defaults . 10 1.3.7 Confirmation . 11 1.3.8 Installation . 12 1.3.9 Finish . 13 1.4 Silent Installation . 14 1.5 Manual Installation . 16 CHAPTER 2 Configuration . 17 2.1 Overview . 17 2.1.1 Preferences GUI . 18 2.1.2 Settings files . 29 2.2 Global . 29 2.2.1 General . 29 2.2.2 Misc . 32 2.2.3 Auto . 35 2.3 File Types . 36 2.3.1 File types . 36 2.3.2 File extensions . 37 2.4 Environment . 38 2.4.1 Custom variables . 38 2.4.2 System variables . 40 2.4.3 Local variables . 41 2.4.4 Usage . 42 2.4.5 Date/Time . 44 2.5 Exclusions . 44 2.5.1 Exclusion patterns . 45 2.6 Messages . 46 2.6.1 Categories . 47 2.6.2 Logging . 48 2.6.3 Misc . 49 2.7 Repository . 49 2.7.1 Searching the repository . 50 2.7.2 Displaying info about the repository . 50 2.7.3 Adding libraries to the repository . 50 2.7.4 Removing the repository . -
C Style and Coding Standards
-- -- -1- C Style and Coding Standards Glenn Skinner Suryakanta Shah Bill Shannon AT&T Information System Sun Microsystems ABSTRACT This document describes a set of coding standards and recommendations for programs written in the C language at AT&T and Sun Microsystems. The purpose of having these standards is to facilitate sharing of each other’s code, as well as to enable construction of tools (e.g., editors, formatters). Through the use of these tools, programmers will be helped in the development of their programs. This document is based on a similar document written by L.W. Cannon, R.A. Elliott, L.W. Kirchhoff, J.H. Miller, J.M. Milner, R.W. Mitze, E.P. Schan, N.O. Whittington at Bell Labs. -- -- -2- C Style and Coding Standards Glenn Skinner Suryakanta Shah Bill Shannon AT&T Information System Sun Microsystems 1. Introduction The scope of this document is the coding style used at AT&T and Sun in writing C programs. A common coding style makes it easier for several people to cooperate in the development of the same program. Using uniform coding style to develop systems will improve readability and facilitate maintenance. In addition, it will enable the construction of tools that incorporate knowledge of these standards to help programmers in the development of programs. For certain style issues, such as the number of spaces used for indentation and the format of variable declarations, no clear consensus exists. In these cases, we have documented the various styles that are most frequently used. We strongly recommend, however, that within a particular project, and certainly within a package or module, only one style be employed. -
Subroutines – Get Efficient
Subroutines – get efficient So far: The code we have looked at so far has been sequential: Subroutines – getting efficient with Perl do this; do that; now do something; finish; Problem Bela Tiwari You need something to be done over and over, perhaps slightly [email protected] differently depending on the context Solution Environmental Genomics Thematic Programme Put the code in a subroutine and call the subroutine whenever needed. Data Centre http://envgen.nox.ac.uk Syntax: There are a number of correct ways you can define and use Subroutines – get efficient subroutines. One is: A subroutine is a named block of code that can be executed as many times #!/usr/bin/perl as you wish. some code here; some more here; An artificial example: lalala(); #declare and call the subroutine Instead of: a bit more code here; print “Hello everyone!”; exit(); #explicitly exit the program ############ You could use: sub lalala { #define the subroutine sub hello_sub { print "Hello everyone!\n“; } #subroutine definition code to define what lalala does; #code defining the functionality of lalala more defining lalala; &hello_sub; #call the subroutine return(); #end of subroutine – return to the program } Syntax: Outline review of previous slide: Subroutines – get efficient Syntax: #!/usr/bin/perl Permutations on the theme: lalala(); #call the subroutine Defining the whole subroutine within the script when it is first needed: sub hello_sub {print “Hello everyone\n”;} ########### sub lalala { #define the subroutine The use of an ampersand to call the subroutine: &hello_sub; return(); #end of subroutine – return to the program } Note: There are subtle differences in the syntax allowed and required by Perl depending on how you declare/define/call your subroutines. -
COBOL-Skills, Where Art Thou?
DEGREE PROJECT IN COMPUTER ENGINEERING 180 CREDITS, BASIC LEVEL STOCKHOLM, SWEDEN 2016 COBOL-skills, Where art Thou? An assessment of future COBOL needs at Handelsbanken Samy Khatib KTH ROYAL INSTITUTE OF TECHNOLOGY i INFORMATION AND COMMUNICATION TECHNOLOGY Abstract The impending mass retirement of baby-boomer COBOL developers, has companies that wish to maintain their COBOL systems fearing a skill shortage. Due to the dominance of COBOL within the financial sector, COBOL will be continually developed over at least the coming decade. This thesis consists of two parts. The first part consists of a literature study of COBOL; both as a programming language and the skills required as a COBOL developer. Interviews were conducted with key Handelsbanken staff, regarding the current state of COBOL and the future of COBOL in Handelsbanken. The second part consists of a quantitative forecast of future COBOL workforce state in Handelsbanken. The forecast uses data that was gathered by sending out a questionnaire to all COBOL staff. The continued lack of COBOL developers entering the labor market may create a skill-shortage. It is crucial to gather the knowledge of the skilled developers before they retire, as changes in old COBOL systems may have gone undocumented, making it very hard for new developers to understand how the systems work without guidance. To mitigate the skill shortage and enable modernization, an extraction of the business knowledge from the systems should be done. Doing this before the current COBOL workforce retires will ease the understanding of the extracted data. The forecasts of Handelsbanken’s COBOL workforce are based on developer experience and hiring, averaged over the last five years. -
Subroutines and Control Abstraction
Subroutines and Control Abstraction CSE 307 – Principles of Programming Languages Stony Brook University http://www.cs.stonybrook.edu/~cse307 1 Subroutines Why use subroutines? Give a name to a task. We no longer care how the task is done. The subroutine call is an expression Subroutines take arguments (in the formal parameters) Values are placed into variables (actual parameters/arguments), and A value is (usually) returned 2 (c) Paul Fodor (CS Stony Brook) and Elsevier Review Of Memory Layout Allocation strategies: Static Code Globals Explicit constants (including strings, sets, other aggregates) Small scalars may be stored in the instructions themselves Stack parameters local variables temporaries bookkeeping information Heap 3 dynamic allocation(c) Paul Fodor (CS Stony Brook) and Elsevier Review Of Stack Layout 4 (c) Paul Fodor (CS Stony Brook) and Elsevier Review Of Stack Layout Contents of a stack frame: bookkeeping return Program Counter saved registers line number static link arguments and returns local variables temporaries 5 (c) Paul Fodor (CS Stony Brook) and Elsevier Calling Sequences Maintenance of stack is responsibility of calling sequence and subroutines prolog and epilog Tasks that must be accomplished on the way into a subroutine include passing parameters, saving the return address, changing the program counter, changing the stack pointer to allocate space, saving registers (including the frame pointer) that contain important values and that may be overwritten by the callee, changing the frame pointer to refer to the new frame, and executing initialization code for any objects in the new frame that require it. Tasks that must be accomplished on the way out include passing return parameters or function values, executing finalization code for any local objects that require it, deallocating the stack frame (restoring the stack pointer), restoring other saved registers (including the frame pointer), and restoring the program counter. -
A Subroutine's Stack Frames Differently • May Require That the Steps Involved in Calling a Subroutine Be Performed in Different Orders
Chapter 04: Instruction Sets and the Processor organizations Lesson 14 Use of the Stack Frames Schaum’s Outline of Theory and Problems of Computer Architecture 1 Copyright © The McGraw-Hill Companies Inc. Indian Special Edition 2009 Objective • To understand call and return, nested calls and use of stack frames Schaum’s Outline of Theory and Problems of Computer Architecture 2 Copyright © The McGraw-Hill Companies Inc. Indian Special Edition 2009 Calling a subroutine Schaum’s Outline of Theory and Problems of Computer Architecture 3 Copyright © The McGraw-Hill Companies Inc. Indian Special Edition 2009 Calls to the subroutines • Allow commonly used functions to be written once and used whenever they are needed, and provide abstraction, making it easier for multiple programmers to collaborate on a program • Important part of virtually all computer languages • Function calls in a C language program • Also included additional functions from library by including the header files Schaum’s Outline of Theory and Problems of Computer Architecture 4 Copyright © The McGraw-Hill Companies Inc. Indian Special Edition 2009 Difficulties when Calling a subroutine Schaum’s Outline of Theory and Problems of Computer Architecture 5 Copyright © The McGraw-Hill Companies Inc. Indian Special Edition 2009 Difficulties involved in implementing subroutine calls 1. Programs need a way to pass inputs to subroutines that they call and to receive outputs back from them Schaum’s Outline of Theory and Problems of Computer Architecture 6 Copyright © The McGraw-Hill Companies Inc. Indian Special Edition 2009 Difficulties involved in implementing subroutine calls 2. Subroutines need to be able to allocate space in memory for local variables without overwriting any data used by the subroutine-calling program Schaum’s Outline of Theory and Problems of Computer Architecture 7 Copyright © The McGraw-Hill Companies Inc. -
Chapter 9: Functions and Subroutines – Reusing Code. Page 125 Chapter 9: Functions and Subroutines – Reusing Code
Chapter 9: Functions and Subroutines – Reusing Code. Page 125 Chapter 9: Functions and Subroutines – Reusing Code. This chapter introduces the use of Functions and Subroutines. Programmers create subroutines and functions to test small parts of a program, reuse these parts where they are needed, extend the programming language, and simplify programs. Functions: A function is a small program within your larger program that does something for you. You may send zero or more values to a function and the function will return one value. You are already familiar with several built in functions like: rand and rgb. Now we will create our own. Illustration 22: Block Diagram of a Function © 2014 James M. Reneau (CC BY-NC-SA 3.0 US) Chapter 9: Functions and Subroutines – Reusing Code. Page 126 Function functionname( argument(s) ) statements End Function Function functionname$( argument(s) ) statements End Function The Function statement creates a new named block of programming statements and assigns a unique name to that block of code. It is recommended that you do not name your function the same name as a variable in your program, as it may cause confusion later. In the required parenthesis you may also define a list of variables that will receive values from the “calling” part of the program. These variables belong to the function and are not available to the part of the program that calls the function. A function definition must be closed or finished with an End Function. This tells the computer that we are done defining the function. The value being returned by the function may be set in one of two ways: 1) by using the return statement with a value following it or 2) by setting the function name to a value within the function. -
A Description of One Programmer's Programming Style Revisited
A Description of One Programmer’s Programming Style Revisited Adam N. Rosenberg 1990 August 1 2001 October 1 ABSTRACT We present the outlook of a programmer at AT&T Bell Labs who has written much code during his eight years there and thirteen years in other places. This document describes the author’s own programming style and what he considers important in generating reli- able, readable, and maintainable code. Since this document is the opinions and prejudices of an individual, it is written in the first person in a conversational tone, and with subjects covered in no particular order. It is intended to be a repository of good questions rather than a source of answers. The author feels that many programmers suffer from gross inattention to detail in writing code. He suggests that clarity and consistency will be rewarded sooner than most people think. A veteran of many languages and operating systems, the author today finds himself using the MS-DOS and UNIXr operating systems and the FORTRAN and C languages. The examples here are all either FORTRAN or C. A decade later the author feels that programming productivity in our “post modern” world has decreased sharply from 1990 to 2000. Many of the reasons for this decline were discussed in the original version of this paper. Our pleasure in prescient prognostication is mitigated by frustration with the “dumbing down” of computing in general. Based on this unhappy downturn of programming education and style, we have added materal (in italics) emphasizing areas of recent concern. The original text and examples (still in regular type) have been left virtually intact. -
Object Oriented Programming*
SLAC-PUB-5629 August 1991 ESTABLISHED 1962 (T/E/I) Object Oriented Programming* Paul F. Kunz Stanford Linear Accelerator Center Stanford University Stanford, California 94309, USA ABSTRACT This paper is an introduction to object oriented programming. The object oriented approach is very pow- erful and not inherently difficult, but most programmers find a relatively high threshold in learning it. Thus, this paper will attempt to convey the concepts with examples rather than explain the formal theory. 1.0 Introduction program is a collection of interacting objects that commu- nicate with each other via messaging. To the FORTRAN In this paper, the object oriented programming tech- programmer, a message is like a CALL to a subroutine. In niques will be explored. We will try to understand what it object oriented programming, the message tells an object really is and how it works. Analogies will be made with tra- what operation should be performed on its data. The word ditional programming in an attempt to separate the basic method is used for the name of the operation to be carried concepts from the details of learning a new programming out. The last key idea is that of inheritance. This idea can language. Most experienced programmers find there is a not be explained until the other ideas are better understood, relatively high threshold in learning the object oriented thus it will be treated later on in this paper. techniques. There are a lot of new words for which one An object is executable code with local data. This data needs to know the meaning in the context of a program; is called instance variables.