Merge pull request #4 from fortran-fans/improve_fft_interface

Improve fft interface for `complex` sequences: `zffti/zfftf/zfftb/fft/ifft`

Author: zoziha

.github/workflows/fpm.yml

@@ -54,4 +54,4 @@ jobs:
     - name: Run tests
       run: |
         gfortran --version
-        fpm test --flag "-O2" tstfft
+        fpm test --flag "-O2"

.gitignore

@@ -4,4 +4,7 @@ build*
 *.o
 *.a
 *.so
-*.x
+*.x
+
+# API-doc
+API-doc/

API-doc-FORD-file.md

@@ -0,0 +1,74 @@
+---
+project: fftpack
+summary: A opensource package fftpack v4.0.0 for (modern) Fortran
+src_dir: src/
+output_dir: API-doc
+page_dir: doc/
+media_dir: doc/media
+display: public
+         protected
+source: true
+proc_internals: true
+md_extensions: markdown.extensions.toc
+graph: true
+graph_maxnodes: 250
+graph_maxdepth: 5
+coloured_edges: true
+sort: permission-alpha
+extra_mods: iso_fortran_env:https://gcc.gnu.org/onlinedocs/gfortran/ISO_005fFORTRAN_005fENV.html
+            iso_c_binding:https://gcc.gnu.org/onlinedocs/gfortran/ISO_005fC_005fBINDING.html#ISO_005fC_005fBINDING
+print_creation_date: true
+creation_date: %Y-%m-%d %H:%M %z
+project_github: https://github.com/certik/fftpack
+license: by-sa
+author: Paul N. Swarztrauber & fftpack contributors
+github: https://github.com/certik/fftpack
+dbg: true
+parallel: 4
+---
+
+[TOC]
+
+@warning This API documentation for the certik/fftpack v4.0.0 is a work in progress.
+
+Fortran FFTPACK API Documentation
+=================================
+
+This is the main API documentation landing page generated by [FORD].
+The documentation for comment markup in source code, running [FORD] and the [FORD project file] are all maintained on the [FORD wiki].
+
+[FORD]: https://github.com/Fortran-FOSS-Programmers/ford#readme
+[FORD wiki]: https://github.com/Fortran-FOSS-Programmers/ford/wiki
+[FORD project file]: https://github.com/certik/fftpack/blob/master/API-doc-FORD-file.md
+
+A package of fortran subprograms for the fast fourier transform of periodic and other symmetric sequences.
+
+## Getting started
+### Get the code
+```bash
+git clone https://github.com/certik/fftpack.git
+cd fftpack
+```
+
+### Build with [fortran-lang/fpm](https://github.com/fortran-lang/fpm)
+Fortran Package Manager (fpm) is a great package manager and build system for Fortran.   
+You can build using provided `fpm.toml`:
+```bash
+fpm build --flag "-O2"
+fpm test --flag "-O2" tstfft
+```
+To use `fftpack` within your `fpm` project, add the following to your `fpm.toml` file:
+```toml
+[dependencies]
+fftpack = { git="https://github.com/certik/fftpack.git" }
+```
+
+## Build with Make
+Alternatively, you can build using provided `Makefile`:
+```bash
+make
+```
+
+## Links
+[netlib/dfftpack1.0(fftpack4.0)](http://www.netlib.org/fftpack/)
+

doc/index.md

@@ -0,0 +1,6 @@
+---
+title: Contributing and specs
+---
+
+@warning
+This page is currently under construction!