Download Week 2 - Intro to Fortran I

ATM S 380
Exercise 2
- Introduction to Fortran programming
Exercise goals
•
Learn basics of Fortran programming
•
Practice writing, compiling, running simple
Fortran codes
Getting started
•
Log on to any computer with your atmos
account
•
Open a terminal (Applications => terminal)
Fortran
•
http://www.cs.mtu.edu/~shene/COURSES/cs201/NOTES/intro.html
•
other documents
•
https://www.stat.tamu.edu/~jnewton/604/chap7.pdf
•
http://www.uv.es/dogarcar/man/IntrFortran90.pdf
•
http://www.egr.unlv.edu/~ed/fortranv2.1.pdf
•
http://www.fortrantutorial.com/documents/IntroductionToFTN95.pdf
fortran code
•
Create a directory ‘F90’ under ‘ATMS380’
•
Create two text files - mean.f90 and quad.f90
and copy the program from the website.
! ------------------------------------------------------! Computes arithmetic, geometric and harmonic means
! ------------------------------------------------------PROGRAM ComputeMeans
IMPLICIT NONE
REAL :: X = 1.0, Y = 2.0, Z = 3.0
REAL :: ArithMean, GeoMean, HarmMean
WRITE(*,*) 'Data items: ', X, Y, Z
WRITE(*,*)
ArithMean = (X + Y + Z)/3.0
GeoMean = (X * Y * Z)**(1.0/3.0)
HarmMean = 3.0/(1.0/X + 1.0/Y + 1.0/Z)
WRITE(*,*) 'Arithmetic mean = ', ArithMean
WRITE(*,*) 'Geometric mean = ', GeoMean
WRITE(*,*) 'Harmonic Mean = ', HarmMean
END PROGRAM ComputeMeans
mean.f90
compilation and execution
•
Compile the program
>>ifort mean.f90
•
Do you see an executable file ‘a.out’ in the
directory?
>>ls
•
Execute a.out
>>./a.out
! --------------------------------------------------! Solve Ax^2 + Bx + C = 0 given B*B-4*A*C >= 0
! --------------------------------------------------PROGRAM QuadraticEquation
IMPLICIT NONE
REAL :: a, b, c
REAL :: d
REAL :: root1, root2
! read in the coefficients a, b and c
WRITE(*,*) 'A, B, C Please : '
READ(*,*) a, b, c
! compute the square root of discriminant d
d = SQRT(b*b - 4.0*a*c)
! solve the equation
root1 = (-b + d)/(2.0*a) ! first root
root2 = (-b - d)/(2.0*a) ! second root
! display the results
WRITE(*,*)
WRITE(*,*) 'Roots are ', root1, ' and ', root2
END PROGRAM QuadraticEquation
quad.f90
Exercise
•
Write a fortran program ‘var.f90’ that calculates
variance and standard deviation of 10 numbers
(ex. 1-10)