Note on Fortran

Table of Content

• Video Resource
• Fortran Package Manager
  • Change module name after fpm initialized the project
• Variable initialization

Video Resource

• Fortran: Array Language

Fortran Package Manager

Change module name after fpm initialized the project

After changing all the corresponding code, like module name and use statement in the directory src/, you need to go to build/ and update the cache.toml file to the new module name.

Variable initialization

I refer to this discussion in fortran-lang wiki.

One will face race condition with OpenMP if you initialize variable like

real(wp) :: a = 0.0_wp

This way, the variable a will be save variable, and the a variable in each thread will not be independent.

For example, if you have a subroutine like this:

SUBROUTINE test()
  INTEGER :: x = 5
  x = x + 1
  WRITE (*, *) x
END SUBROUTINE test

and then in you program you do

CALL test()
CALL test()
CALL test()
CALL test()
CALL test()

it will print

6
7
8
9
10

Instead, we should initialize variables as

real(wp) :: a
a = 0.0_wp

so that the variable will be automatic variables.

Article tags: Miscellaneous