Monte Carlo integration Fortran 90 #363

depate · 2018-09-04T00:27:42Z

Hi all!

The code was compiled with gfortran (gcc-8.2.0) with the following command:

gfortran -Og -Wall -o montecarlo monte_carlo_pi.f90 .

// The warning or error is concerning the implicit call of the in_circle function.

// Thanks in advance for any suggestion or idea solving this issue.

Compiling the code on an other machine with gfortran -Og -Wall -Werror -o montecarlo monte_carlo.f90 does not raise the error.

Best regards,

Patrik

leios · 2018-09-04T00:55:07Z

Thanks a bunch and welcome to the AAA community!

A few notes:

Please remove the binary from the PR
I don't think the .gitignore is necessary here either
Please put your name in the CONTRIBUTORS.md file in the main directory
This is the first time we have fortran90 in the AAA, so please put the language in the book.json file (following the example of the other languages). Note here that the "lang" value will be the filename extension (here .f90) and the "name" will be the language name (Here Fortran90).
Please also update the monte_carlo_integration.md file with the fortran entry, using the tag you created in the book.json file and following the example from the other languages. Basically, you just need to grab the line numbers for the in-text snippets and then put them in the appropriate spot in the method. It will probably look like this:

{% sample lang="f90" %}
[import:3-10, lang:"fortran"](code/f90/monte_carlo.f90)

Sorry there is so much bookkeeping to do! I'll take a look at the actual code soon. I have a lot of PR's to go through, but this one is Fortran, so it's on my list too.

Thanks again!

leios

So building the book, it says include-codeblock: unknown language fortran, use default

Which would mean that fortran is not indexed by include-codeblock and shouldn't have syntax highlighting, but for some reason the syntax highlighting works anyway, so I guess we can just leave it.

Also: My fortran is a bit rusty, so I asked some stupid questions

leios · 2018-09-21T22:08:53Z

contents/monte_carlo_integration/code/fortran/monte_carlo.f90

@@ -0,0 +1,45 @@
+FUNCTION in_circle(pos_x, pos_y, r) 
+IMPLICIT NONE


I realize that fortran77 doesn't usually have indenting for functions, but I thought everything about F90 did? I don't know if this is standard or not, but it might help with readability

TL;DR: You're right. For the sake of code readability indentation is optionally used. I think I did indent in the other code contributions. I will use a Python-like indentation format, four white spaces respectively. But we can discuss another convention. I am open minded about this.

Some Literature:
As I looked around in the documentation and "standards" there is no definition about how many or if one should use indents at all.

Here there is only indentation for INTERFACE and DO routines with four white spaces, but 2-3 are also legit: https://www.fortran90.org/src/best-practices.html

https://en.wikipedia.org/wiki/Fortran_95_language_features and https://www.csee.umbc.edu/~squire/fortranclass/summary.shtml#Intr suggest that after F90 indentation got used more seriously e.g. in functions and modules as well.

Yeah, it seems inconsistent. I don't care the number of spaced used here, but I think indentation is nice. I used to use 6 spaces because that was what Fortran77 required and I needed backward compatibility for my old boss.

I used to use 6 spaces because that was what Fortran77 required
Ah, that's interesting. I was already wondering, why my programming helper addon in VIM always put 6 spaces in.

leios · 2018-09-21T22:13:42Z

contents/monte_carlo_integration/code/fortran/monte_carlo.f90

+END FUNCTION in_circle 
+
+PROGRAM monte_carlo
+IMPLICIT NONE


Again, a bit of spacing would help readability.

leios · 2018-09-21T22:16:44Z

contents/monte_carlo_integration/code/fortran/monte_carlo.f90

+pi_est   = 4d0 * pi_count / n
+pi_error = 100d0 * (abs(pi_est - pi)/pi)
+
+WRITE(*,*) 'The pi estimate is: ', pi_est


Could we do some formatting here to truncate the number of significant digits output for this result?

leios · 2018-09-21T22:20:18Z

Thanks again! Sorry it took me so long to get to this PR. I'll tackle the other Fortran PR's after this one. It's ultimately good, but maybe add some formatting to the output and some spacing to the functions. The spacing is your call. I am not sure what "standard fortran" looks like nowadays.

leios · 2018-09-22T10:25:52Z

contents/monte_carlo_integration/code/fortran/monte_carlo.f90

+END FUNCTION in_circle 
+
+PROGRAM monte_carlo
+IMPLICIT NONE


I think spacing here for the program block might be nice too. Again, this is inconsistent. If you are adamantly against putting spaces here, I totally understand. It just helps a bit with readability. I am trying to think of what people will be submitting in future fortran methods.

Will be done. I did this in the following contributions as well.

leios · 2018-09-22T20:53:35Z

contents/monte_carlo_integration/code/fortran/monte_carlo.f90

+
+END FUNCTION in_circle 
+
+PROGRAM monte_carlo


to be clear: When I said "spacing" before, I was actually asking to index this block. Sorry for the confusion.

Ok, got it. This feels a bit odd because it's unfamiliar to see Fortran Code this way, but I'll get along with it.

Sorry, typo on my part. I meant "indent."

If it is not standard to indent fortran code, you don't have to. I don't know the standard here. I used to indent my stuff, but my advisor didn't. It seems that fortran doesn't require indenting here: http://www.fortran90.org/src/best-practices.html#modules-and-programs

I am sorry for the misunderstanding.

As I understand the reference one can use indenting optionally. But in this case consistent use of 2, 3 or 4 spaces should be followed.

The reference manual only uses indentation for code control structures like DO blocks etc. But I also saw references, e.g. from companies, that take the indentation further for all structures e.g. FUNCTION and SUBROUTINE procedures.

So we are pretty much free to set our own convention. I would suggest to stick to 'indent all the things' scheme. You, and I guess, many other programmers or reviewers are used to indented source codes. But should any other contributor insist on the more historical 'tightly block and pack all the things', I suggest we may also accept this. Because the reference is only strict about consistency.

It may be nice to look into the history of the different FORTRAN references and their style in the not-yet-done section of the book.

leios

Looks good to me. Thanks for the submission!

depate and others added 7 commits September 3, 2018 22:28

first lines

42e7698

added further code

fb31d58

Figured the use of functions out

3b175e4

Figured the use of functions out

906cc0b

Running program. 1 Warning left. Pi estimate cruel"

0d56e0f

1M samples

d0232d6

formating style

611fda8

june128 added the Implementation This provides an implementation for an algorithm. (Code and maybe md files are edited.) label Sep 4, 2018

depate and others added 2 commits September 4, 2018 11:47

Applied the notes to the PR. Added correct precisions to constants.

3896b3f

Added INTERFACE section to resolve raise of IMPLICIT error

3e5b1e8

Butt4cak3 assigned leios Sep 14, 2018

Merge branch 'master' into monte_carlo_fortran

4d7acdc

leios requested changes Sep 21, 2018

View reviewed changes

Change code according to review comments

2312537

leios reviewed Sep 22, 2018

View reviewed changes

white spaces and spacing

ba7a990

leios reviewed Sep 22, 2018

View reviewed changes

indexed?

269fcc4

leios approved these changes Sep 23, 2018

View reviewed changes

leios merged commit 7994074 into algorithm-archivists:master Sep 23, 2018

depate deleted the monte_carlo_fortran branch October 7, 2019 21:56

		@@ -0,0 +1,45 @@
		FUNCTION in_circle(pos_x, pos_y, r)
		IMPLICIT NONE

Uh oh!

Monte Carlo integration Fortran 90 #363

Monte Carlo integration Fortran 90 #363

Uh oh!

Conversation

depate commented Sep 4, 2018 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

leios commented Sep 4, 2018

Uh oh!

leios left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

leios commented Sep 21, 2018

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

leios Sep 23, 2018 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

leios left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

depate commented Sep 4, 2018 •

edited

Loading

leios Sep 23, 2018 •

edited

Loading