Difference between revisions of "Fortran"
From MohidWiki
(→Subroutine) |
(→Function) |
||
| Line 105: | Line 105: | ||
===Function=== | ===Function=== | ||
| + | <htm> | ||
| + | <pre name="code" class="fortran"> | ||
| + | |||
| + | function bigroot(a,b,c) | ||
| + | |||
| + | !Arguments | ||
| + | real :: a,b,c,bigroot | ||
| + | |||
| + | !Local | ||
| + | real :: root1, root2, test | ||
| + | |||
| + | if(test>=0.0) then | ||
| + | root1 = (-b + sqrt(test))/(2.0*a) | ||
| + | root2 = (-b - sqrt(test))/(2.0*a) | ||
| + | if (root1 .gt. root2) then | ||
| + | bigroot = root1 | ||
| + | else | ||
| + | bigroot = root2 | ||
| + | end if | ||
| + | else | ||
| + | bigroot = -9.0e35 | ||
| + | end if | ||
| + | |||
| + | return | ||
| + | end function bigroot | ||
| + | </pre> | ||
| + | </htm> | ||
===Variables=== | ===Variables=== | ||
Revision as of 03:41, 21 May 2010
Fortran95 is the language of choice to program in MOHID. Although a primitive form of language it proves to be the most efficient and performant in the area of scientific computing. Still widely used in numerical computation.
Contents
MOHID templates
Module
Program
Examples
Hello World program
program helloworld implicit none write (*,*) "Hello world!" end program helloworld
Hello world in a module
module modulehelloworld
contains
subroutine showhelloworld()
write(*,*) "Hello world!"
end subroutine showhelloworld
end module modulehelloworld
program helloworld use modulehelloworld, only: showhelloworld implicit none call showhelloworld end program helloworld
Subroutine
program subfunc
implicit none
real :: a,b,c,root1,root2
logical :: realroots
write (*,*) "Hello world!"
write (*,10)
read (*,*) a,b,c
call solvit(a,b,c,root1,root2,realroots)
write (*,20) root1,root2
if (realroots) then
write(*,*) 'Sorry, there are no real roots'
end if
10 format('Enter 3 coefficients')
20 format('The roots are ', 2f12.6)
end program subfunc
subroutine solvit(a,b,c,root1,root2,realroots)
!Arguments
real ::a,b,c,root1,root2
logical :: realroots
!Locals
real :: test
test = b**2-4*a*c
if(test>=0.0) then
root1 = (-b + sqrt(test))/(2.0*a)
root2 = (-b - sqrt(test))/(2.0*a)
realroots = .true.
else
realroots = .false.
end if
return
end subroutine solvit
Function
function bigroot(a,b,c)
!Arguments
real :: a,b,c,bigroot
!Local
real :: root1, root2, test
if(test>=0.0) then
root1 = (-b + sqrt(test))/(2.0*a)
root2 = (-b - sqrt(test))/(2.0*a)
if (root1 .gt. root2) then
bigroot = root1
else
bigroot = root2
end if
else
bigroot = -9.0e35
end if
return
end function bigroot
Variables
Types
Interface procedure
Arrays
If
Do
Case
Sample
program average
! Read in some numbers and take the average
! As written, if there are no data points, an average of zero is returned
! While this may not be desired behavior, it keeps this example simple
implicit none
real, dimension(:), allocatable :: points
integer :: number_of_points
real :: average_points=0., positive_average=0., negative_average=0.
write (*,*) "Input number of points to average:"
read (*,*) number_of_points
allocate (points(number_of_points))
write (*,*) "Enter the points to average:"
read (*,*) points
! Take the average by summing points and dividing by number_of_points
if (number_of_points > 0) average_points = sum(points) / number_of_points
! Now form average over positive and negative points only
if (count(points > 0.) > 0) then
positive_average = sum(points, points > 0.) / count(points > 0.)
end if
if (count(points < 0.) > 0) then
negative_average = sum(points, points < 0.) / count(points < 0.)
end if
deallocate (points)
! Print result to terminal
write (*,'(a,g12.4)') 'Average = ', average_points
write (*,'(a,g12.4)') 'Average of positive points = ', positive_average
write (*,'(a,g12.4)') 'Average of negative points = ', negative_average
end program average
