Fortran1 - Revision history

GregTourte at 14:06, 22 November 2022

2022-11-22T14:06:13Z

Show changes

GregTourte at 13:40, 22 November 2022

2022-11-22T13:40:08Z

GregTourte at 13:25, 22 November 2022

2022-11-22T13:25:02Z

GregTourte at 13:14, 22 November 2022

2022-11-22T13:14:32Z

GregTourte at 13:03, 22 November 2022

2022-11-22T13:03:25Z

AntonS: /* To go further */

2018-10-30T10:38:27Z

To go further

AntonS: /* To go further */

2018-10-30T10:34:54Z

To go further

AntonS: /* To go further */

2018-10-30T09:30:38Z

To go further

AntonS: /* To go further */

2018-10-30T09:30:16Z

To go further

AntonS: /* If, Do, Select and Other Ways to Control the Flow */

2018-02-08T09:55:53Z

If, Do, Select and Other Ways to Control the Flow

@@ Line 6: / Line 6: @@
 You need to load these modules on BlueCrystal phase 3:
-<syntaxhighlight lang="shell-session">
+<syntaxhighlight lang="shell">
 module add tools/subversion-1.8.4 languages/intel-compiler-16-u2 languages/gcc-7.1.0
 </syntaxhighlight>
@@ Line 12: / Line 12: @@
 The examples are available via svn:
-<syntaxhighlight lang="shell-session">
+<syntaxhighlight lang="shell">
 svn co https://svn.ggy.bris.ac.uk/subversion-open/fortran1/trunk fortran1
 </syntaxhighlight>
@@ Line 20: / Line 20: @@
 This program prints "hello, world" to the screen.
-<syntaxhighlight lang="shell-session">
+<syntaxhighlight lang="shell">
 cd fortran1/examples/example1
 </syntaxhighlight>
@@ Line 26: / Line 26: @@
 You can compile the program by typing:
-<syntaxhighlight lang="shell-session">
+<syntaxhighlight lang="shell">
 gfortran hello_world.f90 -o hello_world.exe
 </syntaxhighlight>
@@ Line 32: / Line 32: @@
 or by typing:
-<syntaxhighlight lang="shell-session">
+<syntaxhighlight lang="shell">
 make
 </syntaxhighlight>
@@ Line 38: / Line 38: @@
 and run it by typing:
-<syntaxhighlight lang="shell-session">
+<syntaxhighlight lang="shell">
 ./hello_world.exe
 </syntaxhighlight>
@@ Line 66: / Line 66: @@
 Open up your text editor and try changing the greeting, just for the heck of it.  Retype '''make''' and re-run it.  We'll adopt a similar strategy for all the other examples we'll meet.  If you ever want to get back to the original version of a program, just type:
-<syntaxhighlight lang="shell-session">
+<syntaxhighlight lang="shell">
 svn revert hello_world.f90
 </syntaxhighlight>
@@ Line 74: / Line 74: @@
 Now try to use the Intel compiler instead of gfortran:
-<syntaxhighlight lang="shell-session">
+<syntaxhighlight lang="shell">
 make clean
 make FC=ifort
@@ Line 81: / Line 81: @@
 or directly:
-<syntaxhighlight lang="shell-session">
+<syntaxhighlight lang="shell">
 ifort hello_world.f90 -o hello_world.exe
 </syntaxhighlight>
@@ Line 91: / Line 91: @@
 As fun as "hello, world" was, let's spice things up a little.  For instance, let's introduce some variables.  We'll need to move to the next example:
-<syntaxhighlight lang="shell-session">
+<syntaxhighlight lang="shell">
 cd ../example2
 </syntaxhighlight>
@@ Line 98: / Line 98: @@
 <syntaxhighlight lang="fortran">
-  character         :: sex       ! a letter e.g. 'm' or 'f'
+character         :: sex       ! a letter e.g. 'm' or 'f'
-  character(len=12) :: name      ! a string
+character(len=12) :: name      ! a string
-  logical           :: wed       ! married?
+logical           :: wed       ! married?
-  integer           :: numBooks  ! must be a whole number
+integer           :: numBooks  ! must be a whole number
-  real              :: height    ! e.g. 1.83 m (good include units in comment)
+real              :: height    ! e.g. 1.83 m (good include units in comment)
-  complex           :: z         ! real and imaginary parts
+complex           :: z         ! real and imaginary parts
 </syntaxhighlight>
@@ Line 113: / Line 113: @@
 <syntaxhighlight lang="fortran">
-  character         :: nucleotide = 'A'            ! DNA has A,C,G & T
+character         :: nucleotide = 'A'            ! DNA has A,C,G & T
-  character(len=50) :: infile = 'yourData.nc', outfile = "myData.nc"
+character(len=50) :: infile = 'yourData.nc', outfile = "myData.nc"
-  logical           :: initialised = .true.        ! or .false.
+logical           :: initialised = .true.        ! or .false.
-  real              :: solConst       = 1.37       ! Solar 'constant' in kW/m^2
+real              :: solConst       = 1.37       ! Solar 'constant' in kW/m^2
-  complex           :: sqrtMinusOne = (0.0,1.0)    ! (real,imag)
+complex           :: sqrtMinusOne = (0.0,1.0)    ! (real,imag)
 </syntaxhighlight>
@@ Line 130: / Line 130: @@
 All '''intrinsic''', i.e. built-in Fortran data types are available in several '''kinds'''. For integers the kind implies the maximum number of digits. For real and complex varaibles and parameters the kind implies the precision and the exponent range. There are several ways to set kinds. The most portable way is use the intrinsic functions:
-<source lang="Fortran">
+<syntaxhighlight lang="Fortran">
 selected_int_kind( r )
 selected_real_kind( [p] [,r] )
-</source>
+</syntaxhighlight>
 where the arguments in square brackets '''[...]''' are optional.
@@ Line 139: / Line 139: @@
 If I need an integer variable to store up to 8 digits of information, I can define it like this:
-<source lang="Fortran">
+<syntaxhighlight lang="Fortran">
 integer, parameter :: int_kind = selected_int_kind( 8 )
 integer( kind=int_kind ) :: i
-</source>
+</syntaxhighlight>
 If I need a real or a complex variable to represent a floating point number with 16 digits after the decimal point and with the decimal exponent range of at least 100, I can define it like this:
-<source lang="Fortran">
+<syntaxhighlight lang="Fortran">
 integer, parameter :: r_kind = selected_real_kind( 16, 100 )
 real( kind=r_kind ) :: r
 complex( kind=r_kind ) :: c
-</source>
+</syntaxhighlight>
 The third program illustrates some arithmetic pitfalls--'''beware!''':
@@ Line 160: / Line 160: @@
 Let's have a play with the programs.  You an compile them by typing:
-<source>
+<syntaxhighlight lang="shell">
 make
-</source>
+</syntaxhighlight>
 and run them by typing, e.g.:
-<source>
+<syntaxhighlight lang="shell">
 ./basic_types.exe
-</source>
+</syntaxhighlight>
 or,
-<source>
+<syntaxhighight lang="shell">
 ./more_types.exe
-</source>
+</syntaxhighlight>
 or,
-<source>
+<syntaxhighlight lang="shell">
 ./pitfalls.exe
-</source>
+</syntaxhighlight>
 Although we compiled our first example ''by-hand'',  we'll be using '''make''' to compile the rest of our example programs, so you won't have to worry about that side of things.  (If you'd like to know more about make, you can take a look at [[Make|our course on make]], presented in a very similar style to this here excursion into Fortran.)

@@ Line 6: / Line 6: @@
 You need to load these modules on BlueCrystal phase 3:
-<syntaxhighlight lang="shell">
+<syntaxhighlight lang="shell-session">
 module add tools/subversion-1.8.4 languages/intel-compiler-16-u2 languages/gcc-7.1.0
 </syntaxhighlight>
@@ Line 12: / Line 12: @@
 The examples are available via svn:
-<syntaxhighlight lang="shell">
+<syntaxhighlight lang="shell-session">
 svn co https://svn.ggy.bris.ac.uk/subversion-open/fortran1/trunk fortran1
 </syntaxhighlight>
@@ Line 20: / Line 20: @@
 This program prints "hello, world" to the screen.
-<syntaxhighlight lang="shell">
+<syntaxhighlight lang="shell-session">
 cd fortran1/examples/example1
 </syntaxhighlight>
@@ Line 26: / Line 26: @@
 You can compile the program by typing:
-<syntaxhighlight lang="shell">
+<syntaxhighlight lang="shell-session">
 gfortran hello_world.f90 -o hello_world.exe
 </syntaxhighlight>
@@ Line 32: / Line 32: @@
 or by typing:
-<syntaxhighlight lang="shell">
+<syntaxhighlight lang="shell-session">
 make
 </syntaxhighlight>
@@ Line 38: / Line 38: @@
 and run it by typing:
-<syntaxhighlight lang="shell">
+<syntaxhighlight lang="shell-session">
 ./hello_world.exe
 </syntaxhighlight>
@@ Line 66: / Line 66: @@
 Open up your text editor and try changing the greeting, just for the heck of it.  Retype '''make''' and re-run it.  We'll adopt a similar strategy for all the other examples we'll meet.  If you ever want to get back to the original version of a program, just type:
-<syntaxhighlight lang="shell">
+<syntaxhighlight lang="shell-session">
 svn revert hello_world.f90
 </syntaxhighlight>
@@ Line 74: / Line 74: @@
 Now try to use the Intel compiler instead of gfortran:
-<syntaxhighlight lang="shell">
+<syntaxhighlight lang="shell-session">
 make clean
 make FC=ifort
@@ Line 81: / Line 81: @@
 or directly:
-<syntaxhighlight lang="shell">
+<syntaxhighlight lang="shell-session">
 ifort hello_world.f90 -o hello_world.exe
 </syntaxhighlight>
@@ Line 91: / Line 91: @@
 As fun as "hello, world" was, let's spice things up a little.  For instance, let's introduce some variables.  We'll need to move to the next example:
-<syntaxhighlight lang="shell">
+<syntaxhighlight lang="shell-session">
 cd ../example2
 </syntaxhighlight>
@@ Line 122: / Line 122: @@
 Fortran also allows us to gives variables certain attributes.  For example, from '''pitfalls.f90''':
-<source lang="fortran">
+<syntaxhighlight lang="fortran">
 real, parameter    :: pi = 3.14159  ! a fixed constant
-</source>
+</syntaxhighlight>
 The '''parameter''' attribute tells you, me and Fortran that '''pi''' is a '''constant'''.  It's fixed and it's a compile-time error if we try to change it.  This is a good thing, since we can catch nasty bugs that can creep in that way.  We never want pi to be anything other than pi, right?!  Assigning '''parameter''' attributes to quantities we know are constant is an example of '''defensive programming''', or ''bug avoidance''!

@@ Line 6: / Line 6: @@
 You need to load these modules on BlueCrystal phase 3:
-<pre>
+<syntaxhighlight lang="shell">
 module add tools/subversion-1.8.4 languages/intel-compiler-16-u2 languages/gcc-7.1.0
-</pre>
+</syntaxhighlight>
 The examples are available via svn:
@@ Line 20: / Line 20: @@
 This program prints "hello, world" to the screen.
-<source>
+<syntaxhighlight lang="shell">
 cd fortran1/examples/example1
-</source>
+</syntaxhighlight>
 You can compile the program by typing:
-<source>
+<syntaxhighlight lang="shell">
 gfortran hello_world.f90 -o hello_world.exe
-</source>
+</syntaxhighlight>
 or by typing:
-<source>
+<syntaxhighlight lang="shell">
 make
-</source>
+</syntaxhighlight>
 and run it by typing:
@@ Line 66: / Line 66: @@
 Open up your text editor and try changing the greeting, just for the heck of it.  Retype '''make''' and re-run it.  We'll adopt a similar strategy for all the other examples we'll meet.  If you ever want to get back to the original version of a program, just type:
-<source>
+<syntaxhighlight lang="shell">
 svn revert hello_world.f90
-</source>
+</syntaxhighlight>
 Although this has all been fairly painless, we have made a very significant step - we are now editing, compiling and running Fortran programs.
@@ Line 74: / Line 74: @@
 Now try to use the Intel compiler instead of gfortran:
-<source>
+<syntaxhighlight lang="shell">
 make clean
 make FC=ifort
-</source>
+</syntaxhighlight>
 or directly:
-<source>
+<syntaxhighlight lang="shell">
 ifort hello_world.f90 -o hello_world.exe
-</source>
+</syntaxhighlight>
 Run it and make sure the output is the same.
@@ Line 91: / Line 91: @@
 As fun as "hello, world" was, let's spice things up a little.  For instance, let's introduce some variables.  We'll need to move to the next example:
-<source>
+<syntaxhighlight lang="shell">
 cd ../example2
-</source>
+</syntaxhighlight>
 Fortran has several '''intrinsic''', or built-in, types. Every variable must be given a type. Take a look in '''basic_types.f90''':
-<source lang="fortran">
+<syntaxhighlight lang="fortran">
    character         :: sex       ! a letter e.g. 'm' or 'f'
    character(len=12) :: name      ! a string
@@ Line 104: / Line 104: @@
    real              :: height    ! e.g. 1.83 m (good include units in comment)
    complex           :: z         ! real and imaginary parts
-</source>
+</syntaxhighlight>
 This set of types suffice for a great many programs.  The above are all single entities.  We'll meet arrays of things in a couple of examples time.  In ''Fortran2'', we'll also meet user-defined types.  These allow us to group instances of intrinsic types together forming new kinds of thing--new types.  User-defined types are the ''bees knees'' and can make programs much easier to work with.  We'll leave the details to that later course, however.
@@ Line 112: / Line 112: @@
 It's often a good idea to give variables an initial value when we declare them (working with uninitialised variables in another common source of bugs).  This time we're looking at '''more_types.f90''':
-<source lang="fortran">
+<syntaxhighlight lang="fortran">
    character         :: nucleotide = 'A'            ! DNA has A,C,G & T
    character(len=50) :: infile = 'yourData.nc', outfile = "myData.nc"
@@ Line 118: / Line 118: @@
    real              :: solConst       = 1.37       ! Solar 'constant' in kW/m^2
    complex           :: sqrtMinusOne = (0.0,1.0)    ! (real,imag)
-</source>
+</syntaxhighlight>
 Fortran also allows us to gives variables certain attributes.  For example, from '''pitfalls.f90''':

@@ Line 12: / Line 12: @@
 The examples are available via svn:
-<pre>
+<syntaxhighlight lang="shell">
 svn co https://svn.ggy.bris.ac.uk/subversion-open/fortran1/trunk fortran1
-</pre>
+</syntaxhighlight>
 =hello, world=
@@ Line 38: / Line 38: @@
 and run it by typing:
-<source>
+<syntaxhighlight lang="shell">
 ./hello_world.exe
-</source>
+</syntaxhighlight>
 Examine the contents of hello_world.f90, using '''cat''', '''less''', '''more''' or your favourite text editor, and you'll see:
-<source lang="fortran">
+<syntaxhighlight lang="fortran">
+!
 ! This is a comment line.
@@ Line 55: / Line 55: @@
    write(*,*)  "hello, world"
 end program hello_world
-</source>
+</syntaxhighlight>
 We have:

← Older revision		Revision as of 10:38, 30 October 2018
Line 613:		Line 613:

	Norman S. Clerman, Walter Spector, '''Modern Fortran: Style and Usage''', Cambridge, 2012, Queens Building Library QA76.73.F25 CLE.		Norman S. Clerman, Walter Spector, '''Modern Fortran: Style and Usage''', Cambridge, 2012, Queens Building Library QA76.73.F25 CLE.
		+
		+	Jeanne C Adams et al, '''The Fortran 2003 handbook''', Springer, 2009, Queens Building Library QA76.73.F25 FOR.

	Take a look at the [[A_Good_Read\|'A Good Read?']] page for more details.		Take a look at the [[A_Good_Read\|'A Good Read?']] page for more details.

@@ Line 604: / Line 604: @@
 Michael Metcalf, John Reid and Malcolm Cohen, '''Modern Fortran explained''', Oxford, 2018, Queens Building Library QA76.73.F25 MET.
-Walter S. Brainerd, '''Guide to Fortran 2008 programming''', Springer, 2015.
+Ian Chivers, Jane Sleightholme, '''Introduction to programming with Fortran''', Springer, Fourth edition, 2018, Queens Building Library QA76.73.F25 CHI.
-Ian Chivers, Jane Sleightholme, '''Introduction to programming with Fortran : with coverage of Fortran 90, 95, 2003, 2008 and 77''',
+Walter S. Brainerd, '''Guide to Fortran 2008 programming''', Springer, 2015, Queens Building Library QA76.73.F25 BRA.
-Richard J. Hanson, Tim Hopkins, '''Numerical computing with modern Fortran''', SIAM, 2013.
+Richard J. Hanson, Tim Hopkins, '''Numerical computing with modern Fortran''', SIAM, 2013, Queens Building Library, QA76.73.F25 HAN.
-Arjen Markus, '''Modern Fortran in Practice''', Cambridge, 2012.
+Arjen Markus, '''Modern Fortran in Practice''', Cambridge, 2012, Queens Building Library QA76.73.F25 MAR.
 Take a look at the [[A_Good_Read|'A Good Read?']] page for more details.

@@ Line 601: / Line 601: @@
 We recommend using the most up to date Fortran books, e.g:
 Walter S. Brainerd, '''Guide to Fortran 2008 programming''', Springer, 2015.
@@ Line 613: / Line 615: @@
 Norman S. Clerman, Walter Spector, '''Modern Fortran: Style and Usage''', Cambridge, 2012.
 Take a look at the [[A_Good_Read|'A Good Read?']] page for more details.

@@ Line 256: / Line 256: @@
    ii = 0
    do
-      random_value = rand()
+      call random_number( random_value )
       if (random_value .gt. threshold) then
          print*, 'counter is:', ii, random_value, '>', threshold, 'stopping.'