Welcome from Python!

Here is a cheat sheet of plantFEM for python users.

Here is a typical plantFEM (.f90) script.

use plantfem

implicit none

! COMMENT

! Declare variables used in the script.
integer(int32)::[variable_name]
real(real64)::[variable_name]
type([some struct-name or class-name])::[variable_name]
...

! Write what to do
...

end

Question	Python (3.4 or later)	plantFEM (and/or Fortran)
How to execute a script?	`python3 [script.py]`	`plantfem [script.f90]`
How to compile a script?	-	`plantfem build [script.f90]`, then, an executable file `server.out` is created.
Need declarations before using it?	No	Yes
How to call external modules/libraries	`import [library_name]`	`use [library_name]`
How to define a function which has return values.	`def func(arg):` 　　`retrun ret`	`function func(arg) result(ret)` `end function func`
How to define a function which does NOT have return values.	`def sub(arg1, arg2, ...):` 　　`return ret`	`subroutine sub(arg1, arg2,...)` `end subroutine sub`
Does indentation have any meaning?	Yes	No
Are there any statements that must be written in a program?	No	Yes, it is `implicit none`
How to call a function with return values?	`ret = func(arg)`	`ret = func(arg)`
How to call a function WITHOUT return values?	`func(arg)`	`call func(arg)`
Should the declarations be written together at the beginning?	No	Yes
How to call class-method or menber variables	`.`	`%`
How to comment-out	`#`	`!`

Types in Python	Types in plantFEM
`int`	`integer(int16)`,`integer(int32)`,or `integer(int64)`
`float`	`real(real32)`,`real(real64)`,or `real(real128)`
`complex`	`complex`,`double complex`, …etc.
`string`	`character`

How to write this (Basic operations)	… in plantFEM?	…and what to declare before calling it?
`for i in range(10):`	`do i=1, 10` `enddo`	`integer(int32)::i`
`if a == b:`	`if(a==b)then` `end if`	-
`if a != b:`	`if(a/=b)then` `end if`	-
`if a > b:`	`if(a > b)then` `end if`	-
`if a < b:`	`if(a < b)then` `end if`	-
`if a < b and a > c:`	`if(a < b .and. a > c)then` `end if`	-
`print(a)`	`call print(a)`	-
`print("hello "+"world!")`	`call print("hello "//"world!")`	-

How to write this (File-IO)	… in plantFEM?	…and what to declare before calling it?
`f = open("text.txt","w")`	`call f%open("text.txt","w")`	`type(IO_)::f`
`f.write("hello)"`	`call f%write("hello")` or `write(f%fh,*) "hello"`	-
`line = f.readline()"`	`line = f.readline()` or `read(f%fh,*) line`	`character(:),allocatable::line`
`int_value = int(line)`	`int_value = fint(line)`	`integer(int32)::int_value`
`real_value = float(line)`	`real_value = freal(line)`	`real(real64)::real_value`
`f.close("hello)"`	`call f%close()`	-

How to write this (Numpy)	… in plantFEM?	…and what to declare before calling it?
`a = np.zeros(5)`	`a = zeros(5)`	`real(real64),allocatable::a(:)`
`a = np.linspace(2.0, 3.0, num=5)`	`a = linspace([2.0d0,3.0d0],5 )`	`real(real64),allocatable::a(:)`
`a = np.arange(3,7)`	`a = arange(3,7)`	`real(real64),allocatable::a(:)`
`a = np.array([2.0, 3.0, 4.0])`	`a = [2.0d0, 3.0d0, 4.0d0]`	`real(real64),allocatable::a(:)`
`a = np.array([2.0, 3.0],[4.0,5.0])`	`a(1,1:2) = [2.0d0, 3.0d0]` `a(2,1:2) = [3.0d0, 4.0d0]` ``	`real(real64),allocatable::a(:,:)` `a = zeros(2,2)`
`dp = np.dot(a,b)` `# a is vector, b is vector`	`dp = dot_product(a,b)`	``
`dp = np.dot(a,b)` `# a is matrix, b is` `# vector or matrix`	`dp = matmul(a,b)`	`real(real64),allocatable::dp(:) ! or dp(:,:)`
`a1 = a[0]` `#index starts from 0 as default.`	`a1 = a(1) ! index starts from 1 as default.`	-
`random_value = np.random.rand()`	`random_value = random.random()`	`type(Random_)::random`
`random_value = np.random.normal(loc=average, scale=standard_deviation)`	`random_value = random.gauss(mu=average, sigma=standard_deviation)`	`type(Random_)::random`
`a = a.T` `#transpose`	`a = transpose(a)`	-
`a = reshape(a,2,2)` `#reshape`	`a = reshape(a,2,2)`	-

What’s this?	Explanation
allocatable	English Japanese `allocatable` is one of the strongest feature of the Fortran. We can create any dynamic arrays of any types, including real, integer, character, and derived data types.
intent	English Japanese

Other features are presented in Documentation