FORTRAN 77
A Very Quick (and Incomplete) Review
… With Some
GrADS-related Examples
Alfredo Ruiz-Barradas
http://www.atmos.umd.edu/~alfredo/fortran/fortran.ppt
Notes from:
http://www.ictp.trieste.it/~manuals/programming/sun/fortran/f77rm/index.html
College Park, MD
February 6, 2006
Fortran Compilers at AOSC
• UNIX:
+ Type: f77
• Linux:
+Type: g77 (Gnu F77 compiler)
-Type man g77 for man pages
-Multiply by 4 any RECL
+Type: ifc (Intel FORTRAN compiler)
-Users Guide under the Documentation section
+ Type: ifort
-Not need for 4*RECL
Elements of FORTRAN: Basic Terms
Some of the FORTRAN basic terms and concepts are:
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A program consists of one or more program units.
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A program unit is a sequence of statements, terminated by an END.
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A statement consists of zero or more key words, symbolic names,
literal constants, statement labels, operators, and special characters.
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Each key word, symbolic name, literal constant, and operator consists
of one or more characters from the FORTRAN character set.
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A character constant can include any valid ASCII character.
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A statement label consists of 1 to 5 digits, with at least one nonzero.
Elements of FORTRAN: Character Set
• The character set consists of the following:
• Uppercase and lowercase letters, A - Z
and a - z
• Numerals 0 - 9
• Special characters--The following list
shows some special characters:
Elements of FORTRAN: Charater Set
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= Equals Assignment
+ Plus
Adds
- Minus Subtracts
* Asterisk Multiply, alternate returns, comments, exponentiation,
stdin, stdout, list-directed I/O
/ Slash
Divide, delimit data, labeled commons, structures, end-ofrecord
() Parenthesis Enclose expressions, complex constants,
equivalence groups, formats, argument lists, subscripts
, Comma Separator for data, expressions, complex constants,
equivalence groups, formats, argument lists, subscripts
. Period Decimal point, delimiter for logical constants and operators,
record fields
‘ Apostrophe Quoted character literal
! Exclamation Comments
Elements of FORTRAN: Simbolic Names
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Symbolic names can be any number of characters long. The standard is 6.
Symbolic names consist of letters, digits, the dollar sign ($), and the
underscore character (_). $ and _ are not standard.
Symbolic names generally start with a letter--never with a digit or dollar sign
($). Names that start with an underscore (_) are allowed, but may conflict
with names in the Fortran and system libraries.
Uppercase and lowercase are not significant; the compiler converts them all
to lowercase.
Example: These names are equivalent:
SFCPRS = 1013.25
sfcprs
= 1013.25
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The space character is not significant.
– Example: These names are equivalent:
IF(PRES.LT.SFCPRS) GO TO 1
IF (PRES .LT. SFCPRS) GO TO 1
Elements of FORTRAN: Symbolic Names
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Examples of symbolic names:
Valid
Invalid
– X2
– DELTA_T
– Y$DOT
2X
_DELTA_T
Y|DOT
Starts with a digit
Starts with an _ (Reserved for the compiler)
There is an invalid Character |
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In general, for any single program unit, different entities cannot have the
same symbolic name.
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Throughout any program of more than one programming unit, no two of the
following can have the same name:
Block data subprograms
Common blocks
Entry points
Function subprograms
Main program
Subroutines
Elements of FORTRAN: Programs and Statements
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Program
A program unit is a sequence of statements, terminated by an END statement. Every
program unit is either a main program or a subprogram. If a program is to be
executable, it must have a main program.There are three types of subprograms:
subroutines, functions, and block data subprograms. The subroutines and functions
are called procedures, which are invoked from other procedures or from the main
program. The block data subprograms are handled by the loader.
Statements
A statement consists of one or more key words, symbolic names, literal constants,
and operators, with appropriate punctuation. In FORTRAN, no keywords are reserved
in all contexts. Most statements begin with a keyword; the exceptions are the
statement function and assignment statements.
Executable or Nonexecutable Statements
Every statement is either executable or nonexecutable. In general, if a statement
specifies an action to be taken at runtime, it is executable. Otherwise, it is
nonexecutable.The nonexecutable statements specify attributes, such as type and
size; determine arrangement or order; define initial data values; specify editing
instructions; define statement functions; classify program units; and define entry
points. In general, nonexecutable statements are completed before execution of the
first executable statement.
Elements of FORTRAN: Fortran Statements
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ACCEPT* ASSIGN* Assignment* AUTOMATIC
BACKSPACE* BLOCK DATA BYTE
CALL* CHARACTER CLOSE* COMMON COMPLEX CONTINUE*
DATA DECODE* DIMENSION DO* DO WHILE* DOUBLE COMPLEX DOUBLE PRECISION
ELSE* ELSE IF* ENCODE* END* END DO* END FILE* END IF* END MAP END STRUCTURE
END UNION ENTRY EQUIVALENCE EXTERNAL
FORMAT FUNCTION
GOTO* GOTO (Assigned)* GOTO (Unconditional)*
IF (Arithmetic)* IF (Block)* IF (Logical)* IMPLICIT INCLUDE INQUIRE* INTEGER INTRINSIC
LOGICAL
MAP
NAMELIST
OPEN* OPTIONS
PARAMETER PAUSE* POINTER PRINT* PRAGMA PROGRAM
REAL RECORD RETURN* REWIND*
SAVE Statement Function STATIC* STOP* STRUCTURE SUBROUTINE*
TYPE UNION VIRTUAL VOLATILE WRITE*
The asterisk (*) in the table indicates an executable statement.
Elements of FORTRAN: Fixed Format
• The standard fixed format source lines are defined as follows:
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–
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The first 72 columns of each line are scanned.
The first five columns must be blank or contain a numeric label.
Continuation lines are identified by a nonblank, nonzero in column 6.
Short lines are padded to 72 characters.
Long lines are truncated.
• Comments and Blank Lines:
– A line with a c, C, *, d, D, or! in column one is a comment line.The d, D,
and! are nonstandard.
– If you put an exclamation mark (!) in any column of the statement field,
except within character literals, then everything after the ! on that line is
a comment.
– A totally blank line is a comment line.
Data Types
• Rules for Data Typing
The name determines the type; that is, the
name of a datum or function determines its
data type, explicitly or implicitly, according
to the following rules:
Data Types
• The first letter of the name determines the
data type implicitly.
• The default implicit typing rule is that if the
first letter of the name is I, J, K, L, M, or N,
then the data type is integer, otherwise it is
real. Example:
GOD is REAL
… unless you specify it as an integer!
CONSTANTS
• CHARACTER: ‘FILEN’
• INTEGER: 3, -9999, 1e10
– Must be in the range (-2147483648, 2147483647).
• REAL: 3.3, -9999., 1.5e8, 1e-3
– Must be in the range (1.175494E-38, 3.402823E+38)
– Real*8: 6D2, -25.3D-7
• Must be in the range (2.225074D-308, 1.797693D+308)
– Real*16: 6Q2, -25.3Q-7
• Must be in the range (3.362Q-4932, 1.20Q+4932)
• COMPLEX: (1,-2) or (1.3,0.4)
• LOGICAL: .TRUE. and .FALSE.
Variables & Arrays
• Variables: A variable is a symbolic name paired with a
storage location. A variable has a name, a value, and a
type. Whatever datum is stored in the location is the
value of the variable.
• Arrays: An array is a named collection of elements of
the same type. It is a nonempty sequence of data and
occupies a group of contiguous storage locations. An
array has a name, a set of elements, and a type. You
can declare an array in any of the following statements:
– DIMENSION statement
– COMMON statement
– Type statements: BYTE, CHARACTER, INTEGER, REAL, and
so forth
Variables & Arrays
• Arrays: Examples:
– DIMENSION LEVEL(10), T(72,73)
– REAL CORR(-3:3)
• In this case, CORR has 7 elements, with CORR(0)
being the 4th element.
Expressions
• An expression is a combination of one or
more operands, zero or more operators,
and zero or more pairs of parentheses.
There are three kinds of expressions:
– An arithmetic expression evaluates to a single
arithmetic value.
– A character expression evaluates to a single
value of type character.
– A logical or relational expression evaluates to
a single logical value.
Expressions
• Arythmetic operators:
– ** Exponentiation
– * Multiplication
– / Division
– + Addition or Unary Plus
– -Subtraction or Unary Minus
– Precedence from left to right: 1) **, 2) *, /, 3)
+, -, except when parenthesis are involved
Expressions
• Character operators:
– // Concatenation:
• a//b, where a, b are characters, or ‘file’//’name’
• Logical operators:
– X.AND.Y Conjunction: Both X & Y are true
– X.OR.Y Disjunction: Either X or Y or both are True.
– …
• Relational operators:
–
–
–
–
–
–
.LT. Less than
.LE. Less than or equal
.EQ. Equal
.NE. Not equal
.GT. Greater than
.GE. Greater than or equal
Expressions
• A constant expression is made up of explicit constants
and parameters and the FORTRAN operators. Each
operand is either itself another constant expression, a
constant, a symbolic name of a constant, or one of the
intrinsic functions called with constant
arguments.Examples: Constant expressions:
–
–
–
–
–
–
–
PARAMETER (L=29002), (P=3.14159), (C='along the ')
PARAMETER ( I=L*2, V=4.0*P/3.0, S=C//'riverrun' )
PARAMETER ( M=MIN(I,L), IA=ICHAR('A') )
PARAMETER ( Q=6.4Q6, D=2.3D9 )
K = 66 * 80
VOLUME = V*10**3
DO I = 1, 20*3
Input and Output
• Two kinds of I/O are:
– formatted,
– Unformatted.
• The two modes of access to files are
– Sequential, and
– direct.
– When you open a file, the access mode is set to either sequential or
direct. If you do not set it explicitly, you get sequential by default.
• The two types of files are:
– External, and
– internal files.
– An external file resides on a physical peripheral device, such as disk or
tape. An internal file is a location in main memory, is of character type,
and is either a variable, substring, array, array element, or a field of a
structured record.
Format Specifiers
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For formatted write statements, if the external representation of a datum is
too large for the field width specified, the specified field is filled with
asterisks (*).
For formatted read statements, if there are fewer items in the list than there
are data fields, the extra fields are ignored.
The most common format codes are:
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–
–
–
–
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–
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A - text string
D - double precision numbers, exponent notation
E - real numbers, exponent notation
F - real numbers, fixed point format
I - integer
X - horizontal skip (space)
/ - vertical skip (newline)
F, D, &E codes have the general form: Fw.d, Dw.d, Ew.d
– w denotes the field width,
– d denotes the number of significant digits
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I & A codes have the form: Iw, Aw
Intrinsic Functions
• Arithmetic:
– ABS, AINT, EXP, NINT, MOD, SQRT, …
• Type Conversion:
– INT, FLOAT, CMPLX, …
• Trigonometric:
– COS, ASIN, …
Examples
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example1.f : General
example2.f : General
example3.f : Using functions
example4.f : Using subroutines
example5.f : Using external routines
example1.f
*234567******************* example1.f **************************
* A tiny program to plot my running times using GrADS
*
****************************************************************
*
PARAMETER(NDAYS=365, UNDEF=-9.99, EMPTY=0.00)
C
Changing to REAL
REAL MIN(NDAYS)
DIMENSION SEC(NDAYS)
C
CHARACTER*27 HEADER
CHARACTER*3 DAY
CHARACTER*28 PATH
C
PATH='/data/temp4/alfredo/fortran/'
C
OPEN(1,FILE=PATH//'runtimes.data',FORM='FORMATTED',
STATUS=‘OLD')
Nonexecutable
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Sequential (by default)
example1.f
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READ (1,2) HEADER
WRITE(*,2) HEADER
WRITE(*,2) '----------------------------'
Undefined value
runtimes.data
DAY DATE
MIN SEC
MON 01072002 -9.99 -9.99
C
TUE 02072002 -9.99 -9.99
WED 03072002 19.00 43.00
ND = 0
THU 04072002 19.00 33.00
1 CONTINUE
FRI 05072002 19.00 33.00
ND = ND+1
SAT 06072002 19.00 27.00
READ (1,3,END=4) DAY,DATE,MIN(ND),SEC(ND)
SUN 07072002 -9.99 -9.99
WRITE(*,3) DAY,DATE,MIN(ND),SEC(ND)
MON 08072002 19.00 46.00
IF((MIN(ND).EQ.EMPTY).AND.(SEC(ND).EQ.EMPTY)) GO TO. .4.
GO TO 1
TUE 15102002 29.00 7.00
WED 16102002 -9.99 -9.99
4 CONTINUE
ND = ND - 1 !Taking away the last line because is blank THU 17102002
FRI 18102002
CLOSE(1)
SAT 19102002
3 FORMAT(A3,2X,I8,2X,F5.2,2X,F5.2)
SUN 20102002
WRITE(*,*)'-------------------------------------------'
MON 21102002
WRITE(*,*)'I AM RUNNING SINCE JULY 1, 2002!!!!!'
TUE 22102002
WRITE(*,*)'THAT IS',ND,' DAYS AGO'
WED 23102002
THU 24102002
C
FRI 25102002
SAT 26102002
No value
SUN 27102002
example1.f
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OPEN(2,FILE=PATH//'runtimes_gr.data',ACCESS='DIRECT',
STATUS='UNKNOWN',FORM='UNFORMATTED',RECL=1)
C
NDNOR = 0
NDSIR = 0
DO N = 1, ND
IF((MIN(N).EQ.UNDEF).OR.(SEC(N).EQ.UNDEF)) THEN
TIME = UNDEF
NDNOR = NDNOR + 1
ELSE
TIME = MIN(N)+SEC(N)/60.
NDSIR = NDSIR + 1
ENDIF
WRITE(2,REC=N) TIME
ENDDO
example1.f
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WRITE(2,REC=ND+1) UNDEF !Just adding 1 and 2 extra
WRITE(2,REC=ND+2) UNDEF !blank lines for plotting purposes
CLOSE(2)
WRITE(*,*)'WELL,',NDSIR,' DAYS LEAVING FOR A RUN'
WRITE(*,*)'AND',NDNOR,' DAYS JUST BEING LAZY'
WRITE(*,*)'-------------------------------------------'
WRITE(*,*)'make ',ND+2,' days in the script file:'
WRITE(*,*)'grads -blc "run runtimes.gs"'
C
2 FORMAT(A27)
C
C f77 example1.f
C ./a.out
END
Output on Screen:
DAY DATE
MIN SEC
--------------------------MON 1072002 -9.99 -9.99
TUE 2072002 -9.99 -9.99
…
WED 16102002 -9.99 -9.99
THU 17102002 0.00 0.00
------------------------------------------I AM RUNNING SINCE JULY 1, 2002!!!!!
THAT IS
108 DAYS AGO
WELL,
75 DAYS LEAVING FOR A RUN
AND
33 DAYS JUST BEING LAZY
------------------------------------------make
110 days in the script file:
grads -blc "run runtimes.gs"
example1.f
GrADS ctl file
Fortran way to write it
DSET /data/temp4/alfredo/fortran/runtimes_gr.data
UNDEF -9.99
TITLE My running times. Seconds have been divided by 60 to make them
*
decimal
*
XDEF 1 LINEAR 1 1
OPEN(2,FILE=PATH//'runtimes_gr.data',ACCESS='DIRECT',
YDEF 1 LINEAR 1 1
STATUS='UNKNOWN',FORM='UNFORMATTED',RECL=1)
ZDEF 1 LINEAR 1 1
DO N = 1, ND
TDEF 365 LINEAR 1jul2002 1dy
WRITE(2,REC=N) TIME
*
ENDDO
VARS 1
a 1 99 times in minutes
ENDVARS
example1.f
example2.f
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*234567
*************************** example2.f *******************************
***** A LITTLE PROGRAM TO READ index_19502000.txt CONTAINING THE
*****
FOLLOWING FORMATED DATA
*
* STANDARDIZED NORTHERN HEMISPHERE TELECONNECTION INDICES
* The anomalies are standardized by the 1950-2000 base period
* monthly means and standard deviations, then a RPCA is applied.
* From: http://www.cpc.ncep.noaa.gov/data/teledoc/telecontents.shtml
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*column 1: Year (yy)
*column 2: Month (mm)
*column 3: North Atlantic Oscillation (NAO)
*column 4: East Atlantic Pattern (EA)
*column 5: East Atlantic Jet Pattern (EA-JET)
*column 6: West Pacific Pattern (WP)
*column 7: East Pacific Pattern (EP)
*column 8: North Pacific Pattern (NP)
*column 9: Pacific/ North American Pattern (PNA)
*column 10: East Atlantic/West Russia Pattern (EA/WR)
*column 11: Scandinavia Pattern (SCA)
*column 12: Tropical/ Northern Hemisphere Pattern (TNH)
*column 13: Polar/ Eurasia Pattern (POL)
*column 14: Pacific Transition Pattern (PT)
*column 15: Subtropical Zonal Pattern (SZ)
*column 16: Asia Summer Pattern (ASU)
example2.f
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*
*PATTERN VALUES ARE SET TO -9.9 FOR MONTHS IN WHICH THE PATTERN IS
*NOT A LEADING MODE
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C
PARAMETER(NTMI=612)
! MONTHS IN THE FILE
PARAMETER(NMI=97, NMF =588) ! MONTHS TO BE READ
PARAMETER(NTM=NMF-NMI+1) ! FROM 01/1958 TO 12/1998
C
REAL NAO(NTMI), NPP(NTMI)
Changing to REAL
C
DIMENSION IYR(NTMI), MES(NTMI), EAP(NTMI), EAJP(NTMI)
DIMENSION WPP(NTMI), EPP(NTMI), PNAP(NTMI), EAWRP(NTMI)
DIMENSION SP(NTMI), TNHP(NTMI), PEP(NTMI), PTP(NTMI), SZP(NTMI)
DIMENSION ASP(NTMI)
DIMENSION X(NTM), Y(NTM), KYEAR(NTM)
C
CHARACTER*28 PATH
PATH='/data/temp4/alfredo/fortran/'
C
C
C
READING INDEX VALUES
Nonexecutable
example2.f
Sequential (by default)
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WRITE(*,*)'READING DATA FILE'
OPEN(1,FILE=PATH//'index_19502000.txt',STATUS='OLD')
C
DO M = 1, NTMI
READ(1,1) IYR(M), MES(M), NAO(M), EAP(M), EAJP(M),
WPP(M), EPP(M), NPP(M), PNAP(M), EAWRP(M),
SP(M), TNHP(M), PEP(M), PTP(M), SZP(M), ASP(M)
ENDDO
CLOSE(1)
1 FORMAT(2I4,14F5.1)
C
WRITE(*,*)'READING THE PERIOD OF INTEREST' 14 REAL F5.1 numbers
DO I = NMI, NMF 2 INTEGER I4 numbers
J = I-NMI+1
index_19502000.txt
X(J) = NAO(I)
1950 1 1.1 -0.3 -9.9 -1.6 -1.0 -9.9 -2.2 3.1 0.4 1.4 -1.6 -9.9 -9.9 -9.9
KYEAR(J) = IYR(I)
1950 2 0.7 1.3 -9.9 -0.7 0.2 -9.9 -0.2 -0.7 -0.8 -9.9 0.1 -9.9 -9.9 -9.9
ENDDO
1950 3 -0.1 0.1 -9.9 0.2 0.6 0.3 -0.3 0.5 0.5 -9.9 -9.9 -9.9 -9.9 -9.9
C
1950 4 0.0 0.0 0.1 -1.9 -0.5 -0.3 -0.3 -0.7 0.2 -9.9 -9.9 -9.9 -9.9 -9.9
…
2000 9 0.8 0.4 -9.9 -2.1 -9.9 -9.9 -0.2 0.3 -0.2 -9.9 -9.9 -9.9 -0.7 -9.9
2000 10 1.1 0.6 -9.9 0.1 0.6 -9.9 -1.1 -0.7 2.1 -9.9 -9.9 -9.9 -9.9 -9.9
2000 11 -0.7 0.6 -9.9 1.1 0.1 -9.9 0.6 -0.9 2.0 0.9 -9.9 -9.9 -9.9 -9.9
2000 12 -0.6 1.8 -9.9 0.7 -0.5 -9.9 1.1 0.1 0.7 1.2 -2.4 -9.9 -9.9 -9.9
example2.f
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C
WRITE(*,*)'SAVING INDEX'
OPEN(2,FILE=PATH//'naoindex_5898.txt',STATUS='UNKNOWN')
OPEN(3,FILE=PATH//'naoindex_5898.dat',STATUS='UNKNOWN')
OPEN(4,FILE=PATH//'naoindex_5898gr.dat',ACCESS='DIRECT',
STATUS='UNKNOWN',FORM='UNFORMATTED',RECL=1)
DO I = 1, NTM
WRITE(2,69) KYEAR(I), X(I)
WRITE(3,*) X(I)
WRITE(4,REC=I) X(I)
ENDDO
CLOSE(2)
CLOSE(3)
CLOSE(4)
69 FORMAT(1X,I4,1X,F5.1)
C
C f77 example2.f
C ./a.out
C
END
Sequential (by default)
example2.f
Output on Screen:
READING DATA FILE
READING THE PERIOD OF INTEREST
SAVING INDEX
naoindex_5898.txt
1958 -1.7 OPEN(2,FILE=PATH//'naoindex_5898.txt',STATUS='UNKNOWN')
1958 -3.1 DO I = 1, NTM
1958 0.6
WRITE(2,69) KYEAR(I), X(I)
1958 -0.7 ENDDO
1958 -2.0 69 FORMAT(1X,I4,1X,F5.1)
1958 -1.5
1958 -1.8
…
1998 -2.0
1998 -0.5
1998 -2.4
1998 0.0
1998 -0.7
1998 1.0
OPEN(3,FILE=PATH//'naoindex_5898.dat',STATUS='UNKNOWN')
DO I = 1, NTM
WRITE(3,*) X(I)
ENDDO
naoindex_5898.dat
-0.7000000
-1.700000
-3.100000
0.6000000
-0.7000000
-2.000000
-1.500000
…
-2.000000
-0.5000000
-2.400000
0.0000000E+00
-0.7000000
1.000000
example2.f
DSET /data/temp4/alfredo/fortran/naoindex_5898gr.dat
UNDEF -9.99
TITLE CPS' Standardized NAO index
*
XDEF 1 LINEAR 1 1
YDEF 1 LINEAR 1 1
ZDEF 1 LINEAR 1 1
TDEF 492 LINEAR 1jan1958 1mo
*
VARS 1
nao 0 99 NAO Index
ENDVARS
GrADS ctl file
Fortran way to write it
OPEN(4,FILE=PATH//'naoindex_5898gr.dat',ACCESS='DIRECT',
STATUS='UNKNOWN',FORM='UNFORMATTED',RECL=1)
DO I = 1, NTM
WRITE(4,REC=I) X(I)
ENDDO
example2.f
example3.f
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****************** example3.f ******************
*234567
* This little program calculates the binomial coefficients
* for a given exponent, and the binomial weights for a possible
* filtering of a data set.
*
PARAMETER (NP=12)
Nonexecutable
DIMENSION BW(NP), C(NP)
C
WRITE(*,*)'GETTING Cs & Bs'
function
DO M = 1, NP+1
MM = M - 1
C(M) = FACT(NP)/(FACT(MM)*FACT(NP-MM))
BW(M) = C(M)/FLOAT(NP**2)
Changing to REAL
WRITE(*,*) MM, C(M), BW(M)
ENDDO
C
END
No External file to read!!
example3.f
Dummy argument
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C
REAL FUNCTION FACT(N)
C
IF((N.EQ.0).OR.(N.EQ.1)) THEN
FACT = 1.
ELSE
IP = N
DO L = N-1, 1, -1
IP = IP*L
ENDDO
FACT = FLOAT(IP)
ENDIF
RETURN
C
C f77 example3.f
C ./a.out
C
END
example3.f
Output on Screen:
GETTING Cs & Bs
0 1.000000
6.9444445E-03
1 12.00000
8.3333336E-02
2 66.00000
0.4583333
3 220.0000
1.527778
4 495.0000
3.437500
5 792.0000
5.500000
6 924.0000
6.416667
7 792.0000
5.500000
8 495.0000
3.437500
9 220.0000
1.527778
10 66.00000
0.4583333
11 12.00000
8.3333336E-02
12 1.000000
6.9444445E-03
WRITE(*,*)'GETTING Cs & Bs'
DO M = 1, NP+1
WRITE(*,*) MM, C(M), BW(M)
ENDDO
example4.f
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****************** example4.f ******************
*234567
*
* NP=# of points to be used for the smoothing process
*
= any other number for binomial smoothing.
* NSMOOTH = # of times to smooth the time series.
*
* TS=Time series for any grid point
* TSM=smoothed time series
*
PARAMETER(NMI=1, NMF=492, NTM=NMF-NMI+1)
PARAMETER(NTMO=492, NTMD=NTMO-NTM, NSMOOTH=2)
PARAMETER(NLON=72, NLAT=73, NGP=NLON*NLAT)
PARAMETER(UNDEF=-9999.0)
C
DIMENSION X(NLON,NLAT,NTM), XM(NLON,NLAT,NTMO),NPS(NSMOOTH)
DIMENSION TS(NTM), Y(NLON,NLAT), TSM(NTMO)
C
CHARACTER*28 PATH
C
CHARACTER*27 FILEI
CHARACTER*28 FILEO
C
Block DATA
DATA NPS/25, 37/
C
PATH='/data/temp4/alfredo/fortran/'
C
FILEI='ssta_5x2.5_5898.data'
FILEO='ssta_5x2.5_5898_r25+r37.data'
Nonexecutables
example4.f
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DO K = 1, NSMOOTH
NP=NPS(K)
WRITE(*,*) 'FILTERING USING A',NP,' POINT RUNNING MEAN'
ENDDO
C
MLOST=(NPS(1)-1)/2+(NPS(2)-1)/2
WRITE(*,*)MLOST,' MONTHS WILL BE LOST'
WRITE(*,*)'AT EACH END OF ANY TIME SERIES'
C
OPEN(10,FILE=PATH//FILEI,FORM='UNFORMATTED',
STATUS='OLD',ACCESS='DIRECT',RECL=NGP)
OPEN(11,FILE=PATH//FILEO,FORM='UNFORMATTED',
STATUS='UNKNOWN',ACCESS='DIRECT',RECL=NGP)
C
WRITE(*,*)'READING ANOMALIES'
DO MNTH = NMI, NMF
Two ways to read the data
M = MNTH-NMI+1
NREC = MNTH
READ(10,REC=NREC) Y
C
READ(10,REC=NREC) (Y(I,J),I=1,NLON),J=1,NLAT)
DO LON=1, NLON
DO LAT = 1, NLAT
X(LON,LAT,M)=Y(LON,LAT)
ENDDO
ENDDO
ENDDO
CLOSE(10)
C
WRITE(*,*)'FILTERING ANOMALIES'
NPT = 0
DO K = 1, NSMOOTH
NPT= NPT + NPS(K)
ENDDO
example4.f
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DO LON=1, NLON
DO LAT = 1, NLAT
C
WRITE(*,*),'LON=',LON,'LAT=',LAT
DO MNTH=1, NTM
TS(MNTH)=X(LON,LAT,MNTH)
ENDDO
C Be careful with UNDEFINED values!
IF((TS(1).EQ.TS(NTM/2)).AND.(TS(1).EQ.TS(NTM))) THEN
DO MNTH = 1, NTMO
XM(LON,LAT,MNTH)=UNDEF
ENDDO
ELSE
MES = NTM
DO K = 1, NSMOOTH
NP=NPS(K)
C
WRITE(*,*)'PASS # ',K
CALL RUNMEAN(TS,MES,NP,TSM,NEWMES)
C
WRITE(*,*)'NEWMES=',NEWMES
DO I = 1, NEWMES
TS(I)=TSM(I)
ENDDO
MES=NEWMES
ENDDO
DO MNTH = 1, NTMO
XM(LON,LAT,MNTH)=UNDEF
ENDDO
DO I = 1, NEWMES
II = I + NTMD/2+(NPT-NSMOOTH)/2
XM(LON,LAT,II)=TS(I)
ENDDO
ENDIF
ENDDO
ENDDO
subroutine
example4.f
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WRITE(*,*)'SAVING FILTERED ANOMALIES'
DO MNTH = 1, NTMO
DO LON = 1, NLON
DO LAT = 1, NLAT
Y(LON,LAT)=XM(LON,LAT,MNTH)
ENDDO
ENDDO
WRITE(11,REC=MNTH) Y
C
WRITE(11,REC=MNTH) (XM(I,J,MNTH),I=1,NLON),J=1,NLAT)
ENDDO
CLOSE(11)
C
END
C
dummy arguments
SUBROUTINE RUNMEAN(X,NTM,NP,XM,NTMNEW)
C
DIMENSION X(NTM), XM(NTMNEW)
Nonexecutable
DIMENSION XX(NTM)
C
NP1 = NP - 1
NP2 = NP1/2
IB = NP2 + 1
IE = NTM - NP2
NTMNEW=IE-IB+1
C
DO I = IB, IE
II = I-IB+1
KI = I - NP2
KF = I + NP2
S = 0.
DO K = KI, KF
W = 1.
IF((K.EQ.KI).OR.(K.EQ.KF)) W = 0.5
S = S + X(K)*W
ENDDO
XM(II) = S/FLOAT(NP1)
ENDDO
C
RETURN
C
C f77 example4.f
C ./a.out
C
END
example4.f
Output on Screen:
FILTERING USING A
25 POINT RUNNING MEAN
FILTERING USING A
37 POINT RUNNING MEAN
30 MONTHS WILL BE LOST
AT EACH END OF ANY TIME SERIES
READING ANOMALIES
FILTERING ANOMALIES
SAVING FILTERED ANOMALIES
GrADS ctl file
Fortran way to write it
DSET /data/temp4/alfredo/fortran/ssta_5x2.5_5898_r25+r37.data
UNDEF -9999.
TITLE Filtered SST anomalies wrt 1958-1998 climatology
*
OPEN(11,FILE=PATH//FILEO,FORM='UNFORMATTED',
XDEF 72 LINEAR 0. 5.
STATUS='UNKNOWN',ACCESS='DIRECT',RECL=NGP)
*
DO MNTH = 1, NTMO
YDEF 73 LINEAR -90. 2.5
DO LON = 1, NLON
*
DO LAT = 1, NLAT
ZDEF 1 LINEAR 1 1
Y(LON,LAT)=XM(LON,LAT,MNTH)
*
ENDDO
TDEF 492 LINEAR JAN1958 1mo
ENDDO
*
WRITE(11,REC=MNTH) Y
VARS 1
ENDDO
ssta 0 99 sst (C) Filtered sea-surface temperature anomalies
ENDVARS
example4.f
example5.f
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*234567************ example5.f *************************
C
C THIS PROGRAM CALCULATES THE CORRELATION BETWEEN A GIVEN TIME SERIES
C AND THE TIME SERIES OF THE GRID POINTS IN A MAP.
C
PARAMETER(UNDEF=-9999.)
PARAMETER(NTM=492, NLON=72, NLAT=73)
PARAMETER(NMESES=1, NTYR=NTM/12)
PARAMETER(NMS=NTYR*NMESES)
PARAMETER(NGP=NLON*NLAT)
PARAMETER(NRECORDS=1)
PARAMETER(IPRINT=0, MAXLAG=1, IMEAN=1, ISEOPT=1)
C
DIMENSION CC(-MAXLAG:MAXLAG), CCV(-MAXLAG:MAXLAG)
DIMENSION SECC(-MAXLAG:MAXLAG)
DIMENSION CCZ(NGP), CORR(NLON,NLAT,-MAXLAG:MAXLAG)
DIMENSION XX(NTM), X(NMS)
DIMENSION YYY(NLON,NLAT), YY(NLON,NLAT,NTM), Y(NMS)
C
INTEGER SEASTS(NMESES), SEASMAP(NMESES)
C
EXTERNAL CCF
C
DATA SEASTS/10/
Changing to INTEGER
DATA SEASMAP/10/
C
CHARACTER*28 PATH
C
CHARACTER*19 FILE1
CHARACTER*20 FILE2
C
PATH='/data/temp4/alfredo/fortran/'
C
FILE1='naoindex_5898gr.dat'
FILE2='ssta_5x2.5_5898.data'
C
Nonexecutable
IMSL routine
example5.f
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OPEN(1,FILE=PATH//FILE1,FORM='UNFORMATTED',
STATUS='OLD',ACCESS='DIRECT',RECL=1)
OPEN(2,FILE=PATH//FILE2,FORM='UNFORMATTED',
STATUS='OLD',ACCESS='DIRECT',RECL=NGP)
OPEN(3,FILE=PATH//'mcorr_naooct_sstoct_5898.data',
FORM='UNFORMATTED',STATUS='UNKNOWN',ACCESS='DIRECT',
RECL=NGP)
C
WRITE(*,*)'GETTING TIME SERIES'
DO MNTH = 1, NTM
READ(1,REC=MNTH) XX(MNTH) !Reading time series
ENDDO
CLOSE(1)
C
WRITE(*,*)'GETTING TIME SERIES FROM MAPS'
DO MNTH = 1, NTM
DO NR = 1, NRECORDS
NREC= NR + NRECORDS*(MNTH-1)
READ(2,REC=NREC) YYY
!Reading maps
DO LO=1, NLON
DO LA = 1, NLAT
YY(LO,LA,MNTH)=YYY(LO,LA)
ENDDO
ENDDO
ENDDO
ENDDO
CLOSE(2)
C
WRITE(*,*)'EXTRACTING MONTHS'
WRITE(*,*)(SEASTS(M),M=1,NMESES),' FROM INDEX'
C
DO NYR = 1, NTYR
DO MES = 1, NMESES
SEAS = SEASTS(MES)
MNTH = SEAS + 12*(NYR-1)
NREC = MES + NMESES*(NYR-1)
X(NREC) = XX(MNTH)
ENDDO
ENDDO
example5.f
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WRITE(*,*)NREC,' MONTHS IN TIME SERIES'
C
WRITE(*,*)'EXTRACTING MONTHS'
WRITE(*,*)(SEASMAP(M),M=1,NMESES),' FROM MAPS'
C
DO NYR = 1, NTYR
DO MES = 1, NMESES
SEAS = SEASMAP(MES)
MNTH = SEAS + 12*(NYR-1)
NREC = MES + NMESES*(NYR-1)
DO LO = 1, NLON
DO LA = 1, NLAT
YY(LO,LA,NREC) = YY(LO,LA,MNTH)
ENDDO
ENDDO
ENDDO
ENDDO
WRITE(*,*)NREC,' MONTHS IN MAPS'
C
WRITE(*,*)'GETTING VARIANCES AND CORRELATIONS'
C
C Reference time series is X, while Y moves
C + values of MAXLAG means that Y is behind(late wrt or lags) X
C - values of MAXLAG means that Y is ahead(early wrt or leads) X
C + values of MAXLAG means that X is ahead(early wrt or leads) Y
C - values of MAXLAG means that X is behind(late wrt or lags) Y
C
WRITE(*,*)'INTO CCF ROUTINE'
DO I = 1, NLON
DO J = 1, NLAT
DO M = -MAXLAG, MAXLAG
CORR(I,J,M)=UNDEF
ENDDO
ENDDO
ENDDO
example5.f
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DO I=1, NLON
DO J = 1, NLAT
DO MNTH =1, NMS
Y(MNTH) = YY(I,J,MNTH)
ENDDO
C Be careful with UNDEFINED values!
IF((Y(1).EQ.Y(NMS/2)).AND.(Y(1).EQ.Y(NMS))) THEN
ELSE
CALL CCF(NMS,X,Y,MAXLAG,IPRINT,ISEOPT,IMEAN,
X1MEAN,Y1MEAN,X1VAR,Y1VAR,CCV,CC,SECC)
DO M = -MAXLAG,MAXLAG
CORR(I,J,M) = CC(M)
ENDDO
ENDIF
ENDDO
ENDDO
WRITE(*,*)'OUT OF CCF ROUTINE'
NR = 0
DO M = -MAXLAG, MAXLAG
DO I = 1, NLON
DO J = 1, NLAT
YYY(I,J) = UNDEF
ENDDO
ENDDO
NR = NR + 1
DO I = 1, NLON
DO J = 1, NLAT
YYY(I,J) = CORR(I,J,M)
ENDDO
ENDDO
WRITE(3,REC=NR) YYY
ENDDO
CLOSE(3)
C
C Do the following before you compile
C source /usr/local/src/vni-3.0/CTT3.0/ctt/bin/cttsetup.csh
C f77 example5.f $LINK_FNL
C ./a.out
C
END
Linking to IMSL routines
example5.f
Output on Screen:
GETTING TIME SERIES
GETTING TIME SERIES FROM MAPS
EXTRACTING MONTHS
10 FROM INDEX
41 MONTHS IN TIME SERIES
EXTRACTING MONTHS
10 FROM MAPS
41 MONTHS IN MAPS
GETTING VARIANCES AND CORRELATIONS
INTO CCF ROUTINE
OUT OF CCF ROUTINE
GrADS ctl file
Fortran way to write it
DSET /data/temp4/alfredo/fortran/mcorr_naojan_sstjan_5898.data
UNDEF -9999.
TITLE Correlation between NAO's JANUARYs and
* JANUARY SST anomalies during the 1958-1998 period.
OPEN(3,FILE=PATH//'mcorr_naooct_sstoct_5898.data',
*
FORM='UNFORMATTED',STATUS='UNKNOWN',ACCESS='DIRECT',
***************************
RECL=NGP)
*
NR=0
XDEF 72 LINEAR 0.0 5.0
DO M = -MAXLAG, MAXLAG
YDEF 73 LINEAR -90.0 2.5
NR = NR + 1
ZDEF 1 LINEAR 1 1
DO I = 1, NLON
DO J = 1, NLAT
TDEF 3 LINEAR jan1958 1mo
YYY(I,J) = CORR(I,J,M)
*
ENDDO
VARS 1
ENDDO
corr
0 99 Correlation (t=2 is at lag=0) WRITE(3,REC=NR) YYY
ENDVARS
ENDDO
example5.f
At the end…
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Have the necessity to use fortran.
Have a book for quick reference.
Make some time for practicing it.
Good Luck!