Analysis Methods in Atmospheric and Oceanic Science

Transcription

1 Analysis Methods in Atmospheric and Oceanic Science AOSC 652 Intro to FORTRAN and Simple Computations: Day 1 Web Site: 8 Sep

2 Linux KDE Environment For more info, see or 2

3 AOSC 652: Student Editor Preferences vi: Courtney, Dolly, Doyeon, Sandra, Sayantan, Silvia, Vitaly, Walt, Youtong emacs: Colleen, Lynn*, Scott nedit / gedit: Greg, Meredith, Scott, Tyler* nano: Meredith, Michael*, Sarah Responses so far from 18 of 19 students enrolled in this class * Experienced user 3

4 Black & White printer in corner: instlab Color printer closer to podium: color Printing To print a text file to the B & W printer: metosrv8{rjs} enscript fcourier9 dinstlab my_first_pgm.f 4

5 Black & White printer in corner: instlab Color printer closer to podium: color Printing To print a text file to the B & W printer: metosrv8{rjs} enscript fcourier9 dinstlab my_first_pgm.f How would we print with full path name? 5

6 Black & White printer in corner: instlab Color printer closer to podium: color Printing To print a text file to the B & W printer: metosrv8{rjs} enscript fcourier9 dinstlab my_first_pgm.f How would we print with full path name? How would we learn more about the enscript command? 6

7 Black & White printer in corner: instlab Color printer closer to podium: color Printing To print a text file to the B & W printer: metosrv8{rjs} enscript fcourier9 dinstlab my_first_pgm.f How would we print with full path name? How would we learn more about the enscript command? What shortcut could we use to print this file? 7

8 Black & White printer in corner: instlab Color printer closer to podium: color Printing To print a text file to the B & W printer: metosrv8{rjs} enscript fcourier9 dinstlab my_first_pgm.f How would we print with full path name? How would we learn more about the enscript command? What shortcut could we use to print this file? How would we print to the color printer? 8

9 Black & White printer in corner: instlab Color printer closer to podium: color Printing To print a text file to the B & W printer: metosrv8{rjs} enscript fcourier9 dinstlab my_first_pgm.f The.aliases.rjs file you copied on Friday, and moved to.alias, had color1 rather than color Edit.alias and change color1 to color 9

10 Black & White printer in corner: instlab Color printer closer to podium: color Printing To print a text file to the B & W printer: metosrv8{rjs} enscript fcourier9 dinstlab my_first_pgm.f To print a postscript file to the Color printer: lpr Pcolor filename.ps 10

11 Black & White printer in corner: instlab Color printer closer to podium: color Printing To print a text file to the B & W printer: metosrv8{rjs} enscript fcourier9 dinstlab my_first_pgm.f To print a postscript file to the Color printer: lpr Pcolor filename.ps How would we learn more about the lpr command? 11

12 Black & White printer in corner: instlab Color printer closer to podium: color Printing To print a text file to the B & W printer: metosrv8{rjs} enscript fcourier9 dinstlab my_first_pgm.f To print a postscript file to the Color printer: lpr Pcolor filename.ps How would we learn more about the lpr command? Can also visit 12

13 In class environment metosrv8 (this room only) Remote Access Remote access ssh aosc-gw.umd.edu (portal) From aosc-gw: ssh halo-vm. (this environment) Can set up a Linux KDE environment if accessing from a Mac Must install UMd Virtual Private Network (VPN) on your remote computer for access to be fully functional We ll describe Remote Access in more detail next week For first 2 weeks of class, students strongly encouraged to complete assignments in this room to gain familiarity with this environment! Everyone should have keycard access to this room: please see Tameka Jones, CSS 3417, if you do not have access 13

14 Prior Software Number of Students C or C++ 4 FORTRAN 5 GrADS 3 IDL 3 Java 1 MATLAB 5 PERL 1 During Week #3 will describe how to use my plotting utility written many years ago Students welcome to use ANY software (other than excel) to produce plots for the entirety of the class PROVIDED you able to interface your plotting software to a file format we will describe in Week 3 (I ll assist w/ this interface) For now, if you d like to plot using anything other than my plotting utility,idl, or MATLAB, please check that you can access this software from this room 14

15 FORTRAN Rules FORTRAN programs are typed in lines of up to characters 15

16 FORTRAN Rules FORTRAN programs are typed in lines of up to characters First lines are reserved for special purposes 16

17 FORTRAN Rules FORTRAN programs are typed in lines of up to characters First lines are reserved for special purposes First statement should be PROGRAM statement (not ironclad) Last statement should be END statement (ironclad) 17

18 FORTRAN Rules What is special designation of first column? 18

19 FORTRAN Rules What is special designation of first column? Note: any character in first column designates a comment! 19

20 FORTRAN Rules What is special designation of first column? Note: any character in first column designates a comment! HINT: any text that appears after! is also treated as a comment 20

21 FORTRAN Rules What is special designation of first column? Note: any character in first column designates a comment! HINT: any text that appears after! is also treated as a comment Question: why might you see something like x = y+z! rjs, in my FORTRAN code? 21

22 FORTRAN Rules In which column does the continuation character appear? 22

23 FORTRAN Rules In which column does the continuation character appear? What does continuation character mean: i.e., what utility does it serve? 23

24 FORTRAN Rules In which column does the continuation character appear? What does continuation character mean: i.e., what utility does it serve? Note: although any character can appear in line 6 to denote continuation, I find it pleasing to always use + to denote continuation 24

25 Object oriented: Important Programming Concepts Suppose A is a vector, B is a matrix, and C is a vector Can write: FORTRAN: A = B * C What provisions have to be met? Must write: dimension a(nmax,mmax),b(nmax),c(mmax) parameter (nmax=365,mmax=114) do i=1,n do j=1,m a(i,j)=b(i)*c(j) enddo enddo 25

26 Object oriented: Important Programming Concepts Suppose A is a vector, B is a matrix, and C is a vector Can write: FORTRAN: A = B * C What provisions have to be met? Could also write: dimension a(nday_max,nyear_max),b(nday_max), + c(nyear_max) parameter (nday_max=365,nyear_max=114) do i=1,nday_max do j=1,nyear_max a(i,j)=b(i)*c(j) enddo enddo 26

27 Important Programming Concepts FORTRAN: An expression a mathematician would find non-sensical: j = j + 1 has important meaning and appears throughout our FORTRAN codes 27

28 Important Programming Concepts FORTRAN: An expression a mathematician would find non-sensical: j = j + 1 has important meaning and appears throughout our FORTRAN codes For example: iyear = iyear +1 xlat = xlat

29 FORTRAN Nomenclature Files whose names end with.f are considered to be FORTRAN source files ASCII file containing FORTRAN commands written according to prescribed syntax The actual FORTRAN code Files whose names end with.o are taken as object files, and are passed directly to the compiler if compiling is requested. Contains machine language See for more info If you were a Computer Sciences major, you might be exposed to machine language: not for the faint of heart Common convention (used by Salawitch/Canty): files whose names end with.e are executable files Multiple.o files can be compiled into a single.e executable The actual FORTRAN program See for more info 29

30 FORTRAN Variable Types Integer Variable name begins with letter I, j, k, l, m, n Floating point Variable name begins with letter a h or o z Character Variable name can begin with any letter Length must be declared via character statement at top of code: Example: character*80 char_example In general, variable names and all of FORTRAN is not case sensitive Exceptions: file names or commands that interact with operating system 30

31 FORTRAN Precision Floating-point Default is single precision: 32 bits or 4 bytes FORTRAN default is: implicit single precision (a-h, o-z) or implicit real*4 (a-h,o-z) Can use double precision: 64 bits or 8 bytes implicit double precision (a-h, o-z) or implicit real*8 (a-h, o-z) Note: the statements double precision x x = will lead to x being represented as something other than E-02 on many compilers How do we need to alter the statement x = for x to be evaluated as E-02? 31

32 FORTRAN Format Statement Example Integer I I4 4 positions reserved 2008 Floating-point F F7.2 Decimal notation 7 positions, 2 of which come after decimal point E 1PE9.2 Scientific notation 9 positions: 1 before decimal point, 2 after decimal point 5.43E-21 Note: if 1P is used in a format statement, and an Fw.d command follows in the same format statement, will get erroneous output unless 0PFw.d is used Character A A8 8 positions AOSC 652 For more info, see: as well as chapter 9 of Ellis 32

33 AOSC 652: Analysis Methods in AOSC Here are the steps that need to be taken to be able to use the Portland F77 compiler. Be sure the following lines appear in your.cshrc file: set path = ($path /usr/local/pgi-9.0.2/linux86-64/9.0-2/bin) setenv PGI /usr/local/pgi setenv LM_LICENSE_FILE $PGI/license.dat 33

34 AOSC 652: Analysis Methods in AOSC Here are the steps that need to be taken to be able to use the Portland F77 compiler. Be sure the following lines appear in your.cshrc file: set path = ($path /usr/local/pgi-9.0.2/linux86-64/9.0-2/bin) setenv PGI /usr/local/pgi setenv LM_LICENSE_FILE $PGI/license.dat Then, create file.pgif77 in your home directory containing: pgf77 c Msave Mbounds traceback $1.f pgf77 o $1.e $1.o 34

35 AOSC 652: Analysis Methods in AOSC Here are the steps that need to be taken to be able to use the Portland F77 compiler. Be sure the following lines appear in your.cshrc file: set path = ($path /usr/local/pgi-9.0.2/linux86-64/9.0-2/bin) setenv PGI /usr/local/pgi setenv LM_LICENSE_FILE $PGI/license.dat Then, create file.pgif77 in your home directory containing: pgf77 c Msave Mbounds traceback $1.f pgf77 o $1.e $1.o Finally, add: alias pf to your.aliases file ~/.pgif77 35

36 AOSC 652: Please Logout in Proper Sequence Logging out is a complicated, multi-step process: 1. Log out of KDE linux 36

37 AOSC 652: Please Logout in Proper Sequence Logging out is a complicated, multi-step process: 1. Log out of KDE linux 2. Quit X11 37