Beginning Fortran Fortran (77) Basics 22 October 2009 text on white background provided for easy printing
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Beginning Fortran
Fortran (77) Basics22 October 2009
*Black text on white background provided for easy printing
Example Code
• Write a program to read in five values of temperature in Fahrenheit and convert to degrees Celsius OR Kelvin OR both.
Your Typical Programc234567 PROGRAM MYPROGRAM
STOP END
Program OptionsProgram Options
Declaration of VariablesDeclaration of Variables
MAIN CODEMAIN CODE
Your Typical Programc234567 PROGRAM MYPROGRAM
STOP END
Program OptionsProgram Options
Declaration of VariablesDeclaration of Variables
MAIN CODEMAIN CODE
Program Declaration
• You declare what kind of Fortran file you are writing on the first line.
• Syntax: <TYPE> <NAME>
c234567
PROGRAM CONVERTF
Program Declaration
• You declare what kind of Fortran file you are writing on the first line.
• Syntax: <TYPE> <NAME>
c234567
PROGRAM CONVERTFSpecifies the file as a program Program name – something short but descriptive
Your Typical Programc234567 PROGRAM CONVERTF
STOP END
Program OptionsProgram Options
Declaration of VariablesDeclaration of Variables
MAIN CODEMAIN CODE
Options and Variables
• There are numerous options – you can Google them if you are interested
• In general, there are two kinds:– You can “include” variables from another *.h file
by putting include ‘<filename>.h’in the options section.
– You can switch on other options about how the code is run (Google it)
– We are going to use implicit none
Options and Variables
• All variables we are going to use must be accounted for in the declaration section (no implicit variables allowed) – implicit none
• What do we need?– Temperature in Fahrenheit, Celsius, Kelvin– Logicals (do we want Celsius, Kelvin, both?)– Some integer to loop through all 5 values– Syntax: <TYPE> <NAME>
Options and Variables
c234567
IMPLICIT NONE
PARAMETER NT = 5
REAL F(NT)
REAL K(NT)
REAL C(NT)
LOGICAL DOC
LOGICAL DOK
INTEGER I
Options and Variables
c234567
IMPLICIT NONE
PARAMETER NT = 5
REAL F(NT)
REAL K(NT)
REAL C(NT)
LOGICAL DOC
LOGICAL DOK
INTEGER I
Specify a special parameter – an unchangeable value that can immediately be used (unlike a variable, which can change value)
Options and Variables
c234567
IMPLICIT NONE
PARAMETER NT = 5
REAL F(NT)
REAL K(NT)
REAL C(NT)
LOGICAL DOC
LOGICAL DOK
INTEGER I
Array of 5 REALs for Fahrenheit temps
Options and Variables
c234567
IMPLICIT NONE
PARAMETER NT = 5
REAL F(NT)
REAL K(NT)
REAL C(NT)
LOGICAL DOC
LOGICAL DOK
INTEGER I
Array of 5 REALs for Kelvin temps
Options and Variables
c234567
IMPLICIT NONE
PARAMETER NT = 5
REAL F(NT)
REAL K(NT)
REAL C(NT)
LOGICAL DOC
LOGICAL DOK
INTEGER I
Array of 5 REALs for Celsius temps
Options and Variables
c234567
IMPLICIT NONE
PARAMETER NT = 5
REAL F(NT)
REAL K(NT)
REAL C(NT)
LOGICAL DOC
LOGICAL DOK
INTEGER I
Logical: Do we want to convert to Celsius (TRUE) or not (FALSE)?
Options and Variables
c234567
IMPLICIT NONE
PARAMETER NT = 5
REAL F(NT)
REAL K(NT)
REAL C(NT)
LOGICAL DOC
LOGICAL DOK
INTEGER I Logical: Do we want to convert to Kelvin (TRUE) or not (FALSE)?
Options and Variables
c234567
IMPLICIT NONE
PARAMETER NT = 5
REAL F(NT)
REAL K(NT)
REAL C(NT)
LOGICAL DOC
LOGICAL DOK
INTEGER IInteger that counts from 1 to 5 for loop over one-dimensional arrays
Your Typical Programc234567 PROGRAM CONVERTF IMPLICIT NONE PARAMETER NT = 5 REAL F(NT) REAL K(NT) REAL C(NT) LOGICAL DOC LOGICAL DOK INTEGER I
STOP END
MAIN CODEMAIN CODE
Main Code
• We need to do several things:– Read in 5 values of temperature– Determine if we need to convert to Celsius, Kelvin,
or both– Output values
FF
From User
FiFi CiCi
KiKiTo User
To User
To User
DOC
DOK
FF
From User
FiFi CiCi
KiKiTo User
To User
To User
Read in 5 values of F into array
DOC
DOK
FF
From User
FiFi CiCi
KiKiTo User
To User
To User
For each of the five temperatures (for-loop):
DOC
DOK
FF
From User
FiFi CiCi
KiKiTo User
To User
To User
Compute C (we are going to do this no matter what, because we know that the output has to either be C or K or both, and we need C in order to calculate K anyway).
DOC
DOK
FF
From User
FiFi CiCi
KiKiTo User
To User
To User
Output F to user (this should be done just to make sure that the input was read correctly).
DOC
DOK
FF
From User
FiFi CiCi
KiKiTo User
To User
To User
If DOC = TRUE, then output C as well.
DOC
DOK
FF
From User
FiFi CiCi
KiKiTo User
To User
To User
If DOK = TRUE, then compute K from C and output to user as well.
DOC
DOK
Main Code
FF
From User
c234567 DO I = 1, NT READ(*,*) F(I) ENDDO
Main Code
FF
From User
c234567 DO I = 1, NT READ(*,*) F(I) ENDDO
READ is a Fortran command that is used for input.Syntax: READ(<location>,<formatting>)
Location (*) = read in from the terminalFormat (*) = no particular format
Main Code
FF
From User
c234567 DO I = 1, NT READ(*,*) F(I) ENDDO WRITE(*,*) ‘Convert to C?’ READ(*,*) DOC WRITE(*,*) ‘Convert to K?’ READ(*,*) DOK
Main Code
FF
From User
c234567 DO I = 1, NT READ(*,*) F(I) ENDDO WRITE(*,*) ‘Convert to C?’ READ(*,*) DOC WRITE(*,*) ‘Convert to K?’ READ(*,*) DOK
Write to screen with no particular formatting.
Main Code
c234567 DO I = 1, NT C(I) = (5./9.)*(F(I)-32.) ENDDO
Main Code
c234567 DO I = 1, NT C(I) = (5./9.)*(F(I)-32.) ENDDO
For each temperature:
Main Code
c234567 DO I = 1, NT C(I) = (5./9.)*(F(I)-32.) ENDDO
For each temperature:Compute Celsius temp.
Main Code
c234567 IF (DOK .EQV. .TRUE.) THEN DO I = 1, NT K(I) = C(I) + 273.15 ENDDO ENDIF
Main Code
c234567 IF (DOK .EQV. .TRUE.) THEN DO I = 1, NT K(I) = C(I) + 273.15 ENDDO ENDIF
Logical trap: If we want to calculate Kelvin:
Main Code
c234567 IF (DOK .EQV. .TRUE.) THEN DO I = 1, NT K(I) = C(I) + 273.15 ENDDO ENDIF
Logical trap: If we want to calculate Kelvin:Loop through temperatures and calculate Kelvin temps.(If DOK = .FALSE., this entire loop is avoided)
Main Codec234567 IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .FALSE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C’ ENDDO ENDIFc IF ((DOC .EQV. .FALSE.) .AND. (DOK .EQV. .TRUE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, K(I), ‘K’ ENDDO ENDIFc IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .TRUE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C ’, K(I), ‘K’ ENDDO ENDIF
Main Codec234567 IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .FALSE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C’ ENDDO ENDIFc IF ((DOC .EQV. .FALSE.) .AND. (DOK .EQV. .TRUE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, K(I), ‘K’ ENDDO ENDIFc IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .TRUE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C ’, K(I), ‘K’ ENDDO ENDIF
c234567 PROGRAM CONVERTF IMPLICIT NONE PARAMETER NT = 5 REAL F(NT) REAL K(NT) REAL C(NT) LOGICAL DOC LOGICAL DOK INTEGER I DO I = 1, NT READ(*,*) F(I) ENDDO WRITE(*,*) ‘Convert to C?’ READ(*,*) DOC WRITE(*,*) ‘Convert to K?’ READ(*,*) DOK DO I = 1, NT C(I) = (5./9.)*(F(I)-32.) ENDDO IF (DOK .EQV. .TRUE.) THEN DO I = 1, NT K(I) = C(I) + 273.15 ENDDO ENDIF IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .FALSE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C’ ENDDO ENDIFc IF ((DOC .EQV. .FALSE.) .AND. (DOK .EQV. .TRUE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, K(I), ‘K’ ENDDO ENDIFc IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .TRUE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C ’, K(I), ‘K’ ENDDO ENDIF STOP END
Program Start
Options/Variable Declaration
Main Code
Program End
c234567 PROGRAM CONVERTF IMPLICIT NONE PARAMETER NT = 5 REAL F(NT) REAL K(NT) REAL C(NT) LOGICAL DOC LOGICAL DOK INTEGER I DO I = 1, NT READ(*,*) F(I) ENDDO WRITE(*,*) ‘Convert to C?’ READ(*,*) DOC WRITE(*,*) ‘Convert to K?’ READ(*,*) DOK DO I = 1, NT C(I) = (5./9.)*(F(I)-32.) ENDDO IF (DOK .EQV. .TRUE.) THEN DO I = 1, NT K(I) = C(I) + 273.15 ENDDO ENDIF IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .FALSE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C’ ENDDO ENDIFc IF ((DOC .EQV. .FALSE.) .AND. (DOK .EQV. .TRUE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, K(I), ‘K’ ENDDO ENDIFc IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .TRUE.)) THEN DO I = 1, NT WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C ’, K(I), ‘K’ ENDDO ENDIF STOP END
Compilation
• Compilation is performed in the terminal:
Syntax:<compiler> -o <exec. filename> <source filename> <options>
Compilation
• Compilation is performed in the terminal:
Syntax:<compiler> -o <exec. filename> <source filename> <options>
Depends on system: f77, g77, pgf77, etc.
Compilation
• Compilation is performed in the terminal:
Syntax:<compiler> -o <exec. filename> <source filename> <options>
We wish to create an object that is an executable file with the following name
Compilation
• Compilation is performed in the terminal:
Syntax:<compiler> -o <exec. filename> <source filename> <options>
Use this *.f file to compile the executable
Compilation
• Compilation is performed in the terminal:
Syntax:<compiler> -o <exec. filename> <source filename> <options>
Also depends on compiler. Some frequent options:Mextend – allows you to go over column 70 in the codeMbounds – if you attempt to reference an array index out of bounds, will notify youMbyteswapio – some formats require a byte-swap
Compilation
• Compilation is performed in the terminal:
Syntax:<compiler> -o <exec. filename> <source filename> <options>
pgf77 –o CONVERTF.exe CONVERTF.f
Related Documents
