CSCE150 Fortran Lab12

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CSCE150 Fortran Lab12
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Outline

• Modules
• example 1
• Derived Data Types
• example 2
• exercise 1
• exercise 2

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Modules

• Fortran 90 has a new type of subprogram called
  modules
• to provide the programmers with a way of packing
  commonly used functions or shared data into a
  single unit
• A module must be saved in a separate .f90 file.

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Syntax of a module

• MODULE module_name
• IMPLICIT NONE
• Declaration of data
• CONTAINS
• Declaration of subroutines or functions
• END MODULE module_name

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Use modules in other program units

• To use a particular module in a program unit, a
  USE statement must be included at the very
  beginning.
• For example
• PROGRAM main_program
• USE my_module
• IMPLICIT NONE
• ..........
• END PROGRAM

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example 1

• MODULE DegreeRadianConversion
• IMPLICIT NONE
• REAL, PARAMETER PI 3.1415926
• CONTAINS
• REAL FUNCTION DegreeToRadian(Degree)
• IMPLICIT NONE
• REAL, INTENT(IN) Degree
• DegreeToRadian DegreePI/180
• END FUNCTION DegreeToRadian
• END MODULE DegreeRadianConversion

example1_module.f90
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example1.f90

• PROGRAM lab12_example1
• USE DegreeRadianConversion
• IMPLICIT NONE
• REAL degree, radian
• WRITE (,) Please enter the degree
• READ (,) degree
• radian DegreeToRadian(degree)
• WRITE(,) The converted radian is, radian
• END PROGRAM

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compile

• f90 example1_module.f90 example1.f90 o example1
• Attention
• The name of the module file is listed before the
  main program file.

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Derived Data Types

• Built-in (intrinsic) data types
• INTEGER
• REAL
• LOGICAL
• CHARACTER
• User-defined (derived) data type
• is a combination of intrinsic data types and
  previously defined derived data types

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Define a derived data type

• TYPE type_name
• INTEGER component_1
• CHARACTER component_2
• ( other component definitions)
• END TYPE type_name

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Declare variables/arrays of a derived data type

• TYPE (type_name) var1, var2
• OR
• TYPE (type_name), DIMENTION(10) array1

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Initialize variables of a derived data type

• var1 type_name (values of components)

Access components of a derived data type
Variable_namecomponent e.g. var1component_1
var2component_1
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example 2

• None of intrinsic unary and binary operators is
  defined for derived data types.
• Fortran permits defining new unary and binary
  operators for both intrinsic and derived data
  types.

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Define , - for a derived data type

• MODULE types
• IMPLICIT NONE
• TYPE my_type
• INTEGER x1, x2
• END TYPE my_type
• ! Declare interface operators
• INTERFACE OPERATOR ()
• MODULE PROCEDURE addition
• END INTERFACE
• INTERFACE OPERATOR (-)
• MODULE PROCEDURE subtraction
• END INTERFACE

example2_module.f90
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• ! Now define the implementing functions
• CONTAINS
• TYPE (my_type) FUNCTION addition (num1, num2)
• IMPLICIT NONE
• TYPE (my_type), INTENT(IN) num1, num2
• ! Calculate the addition
• additionx1 num1x1num2x1
• additionx2 num1x2num2x2
• END FUNCTION addition
• TYPE (my_type) FUNCTION subtraction (num1,
  num2)
• IMPLICIT NONE
• TYPE (my_type), INTENT(IN) num1, num2
• ! Calculate the subtration
• subtractionx1 num1x1-num2x1
• subtractionx2 num1x2-num2x2
• END FUNCTION subtraction
• END MODULE types

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• PROGRAM lab12_example2
• USE types
• IMPLICIT NONE
• TYPE (my_type) number1, number2, sum, sub
• ! Get the first my_type variable from keyboard
• WRITE (,) 'Enter x1, x2 for the first my_type
  variable'
• READ (,) number1x1, number1x2
• ! Get the second my_type variable from keyboard
• WRITE (,) 'Enter x1, x2 for the second my_type
  variable'
• READ (,) number2x1, number2x2
• ! test (addition) operator here
• sum number1 number2
• ! Output result of addition
• WRITE (,102) number1, ', number2, ' ', sum
• 102 FORMAT ('',I4,I4,'',A,'',I4,I4,'',A,'',I4
  ,I4,'')

example2.f90
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(No Transcript)
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exercise 1

• Write a Fortran program to convert radian to
  degree using module
• The formula is
• degree radian 180 / 3.1415
• Refer to example 1

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exercise 2

• Write a Fortran program to define , / for a
  derived data type
• Refer to example 2