Programming in Fortran 95

Download Fortran 95 course, PDF tutorial for beginners to learn the basics of Fortran programming language.

Table of contents

• A very simple program
• Running the program
• Variables and expressions
• Other variable types: integer, complex and character
• Intrinsic functions
• Logical controls
• Advanced use of if and logical comparisons
• Repeating ourselves with loops: do
• The stop statement
• Expressions and the assignment statement
• Control instructions
• The tables
• Reading and writing operations
• The procedures
• Modules
• Structures or derived types
• The DFLIB graphic library
• Procedures: Advanced concepts
• Modules: Advanced concepts
• Pointers
• Optimization notions
• Execution in command lines
• Array arithmetic
• GOOD PROGRAMMING STYLE
• Readability
• Self-checking code
• Write clear code that relates to the physics
• INPUT TO AND OUTPUT FROM A F95 PROGRAM
• F95 statements for I/O
• GRAPHICS AND VISUALISATION
• Plotting a data file
• Getting help
• Further examples
• Printing graphs into PostScript files
• Functions
• Formal definition
• Subroutines
• Local and global variables
• Passing arrays to subroutines and functions
• Size and shape of array known
• Arrays of unknown shape and size
• The intent and save attributes
• USING MODULES
• Modules
• public and private attributes
• NUMERICAL PRECISION AND MORE ABOUT VARIABLES
• Entering numerical values
• Numerical Accuracy

Introduction to Fortran

Machine code (numeric notation in octal);

• mnemonic code assemblers;
• 1954: project creation of the first language symbolic FORTRAN by John Backus from IBM (Mathematical FORmula

TRANslating System):

• Efficiency of generated code (performance);
• Quasi natural language for scientists (productivity, maintenance, readability).
• 1957: Delivery of the first compilers;
• 1958: Fortran II (IBM) ⇒ independently computable sub programs.
• Generalization to other manufacturers but:
• Divergence of extensions ⇒Normalization requirement;
• ASA American Standards Association (ANSI).

Committee for the development of a FORTRAN standard. 1966: Fortran IV (Fortran 66);

• Evolution by divergent extensions. . .
• 1977: Fortran V (Fortran 77).

almost compatible:
no iteration of the null loops (OD I = 1.0)

• Main news:
• type character;
• IF-THEN-ELSE;
• Direct access I / O and OPEN.

Anne Fouilloux Patrick Corde (anne.fouilloux@ecmwf.int Patrick.Corde@idris.fr Language Fortran (Base)) January 29, 2018 8/265
Introduction History

• Work of the X3J3 / ANSI and WG5 / ISO committees to modernize Fortran 77:
• Standardization: inclusion of extensions;
• Development: new concepts already exploited by newer languages APL,

Algol, PASCAL, Ada; . . .

• Performances in scientific computing;
• Fully compatible with Fortran 77.
• 1991/1992: Fortran 90 standard (ISO and ANSI);
• 1994: Fortran 90 Cray and IBM first compilers;
• 1997: Fortran 95 standard (ISO and ANSI);
• 1999: First compilers Fortran 95 on Cray T3E then IBM RS / 6000;
• September 2004: Fortran Standard 2003 (ISO and ANSI);
• October 2010: Fortran Standard 2008 (ISO and ANSI).