https://github.com/jacobwilliams/daglib

Directed Acyclic Graphs With Modern Fortran
https://github.com/jacobwilliams/daglib

directed-acyclic-graph fortran fortran-package-manager graphviz graphviz-dot-language toposort

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Directed Acyclic Graphs With Modern Fortran

• Host: GitHub
• URL: https://github.com/jacobwilliams/daglib
• Owner: jacobwilliams
• License: other
• Created: 2018-01-17T16:43:53.000Z (about 7 years ago)
• Default Branch: master
• Last Pushed: 2023-12-31T20:34:37.000Z (about 1 year ago)
• Last Synced: 2024-11-08T03:09:40.347Z (3 months ago)
• Topics: directed-acyclic-graph, fortran, fortran-package-manager, graphviz, graphviz-dot-language, toposort
• Language: Fortran
• Homepage:
• Size: 899 KB
• Stars: 24
• Watchers: 3
• Forks: 8
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
![daglib](media/logo.png)

============

### Overview

[![Language](https://img.shields.io/badge/-Fortran-734f96?logo=fortran&logoColor=white)](https://github.com/topics/fortran)

![Build Status](https://github.com/jacobwilliams/daglib/actions/workflows/CI.yml/badge.svg)

[![GitHub release](https://img.shields.io/github/release/jacobwilliams/daglib.svg)](https://github.com/jacobwilliams/daglib/releases/latest)

DAGLIB is a modern Fortran module for creating and manipulating directed acyclic graphs (DAGs). It includes a toposort feature, and also the ability to generate files in the [GraphViz](https://www.graphviz.org) "dot" notation.

### Building

A [Fortran Package Manager](https://github.com/fortran-lang/fpm) manifest file is included, so that the library and tests cases can be compiled with FPM. For example:

```

fpm build --profile release

fpm test --profile release

```

By default, the library is built with single precision (`int32`) integer values. Explicitly specifying the integer kind can be done using the following processor flag:

Preprocessor flag | Kind  | Number of bytes

----------------- | ----- | ---------------

`INT8`  | `integer(kind=int8)`  | 1

`INT16` | `integer(kind=int16)` | 2

`INT32` | `integer(kind=int32)` | 4

`INT64` | `integer(kind=int64)` | 8

For example, to build a long integer version of the library:

```

fpm build --profile release --flag "-DINT64"

```

### Example

A simple example is shown below:

```fortran

program dag_example

    use dag_module

    implicit none

    type(dag) :: d

    integer,dimension(:),allocatable :: order

    integer :: istat

    integer :: i

    integer,parameter :: n_nodes = 6

    character(len=*),parameter :: filetype = 'pdf'

    ! create a dag:

    call d%set_vertices(n_nodes)

    call d%set_edges(2,[1])     ! 2 depends on 1

    call d%set_edges(3,[5,1])   ! 3 depends on 5 and 1

    call d%set_edges(4,[5])     ! 4 depends on 5

    call d%set_edges(5,[2])     ! 5 depends on 2

    call d%set_edges(6,[2,4])   ! 6 depends on 2 and 4

    ! toposort:

    call d%toposort(order,istat)

    ! define some styles for the GraphViz output:

    do i = 1, n_nodes

        if (i==3 .or. i==6) then

            call d%set_vertex_info(i,attributes='shape=square,fillcolor="SlateGray1",style=filled')

        else

            call d%set_vertex_info(i,attributes='shape=circle,fillcolor="cornsilk",style=filled')

        end if

    end do

    ! generate the GraphViz output:

    call d%save_digraph('test.dot','RL',300)

    call d%destroy()

    call execute_command_line('dot -Tpdf -o test.pdf test.dot')

end program dag_example

```

This program produces the toposort order:

```

 order = [1, 2, 5, 3, 4, 6]

```

and the image file:

![dag_example](media/dag_example.png)

### Documentation

 * The API documentation for the current ```master``` branch can be found [here](https://jacobwilliams.github.io/daglib/).  This is generated by processing the source files with [FORD](https://github.com/Fortran-FOSS-Programmers/ford).

### License

This library is released under a [BSD-3 license](https://github.com/jacobwilliams/daglib/blob/master/LICENSE).

### See also

  * [dag](https://github.com/sourceryinstitute/dag) (a fork of this project)