keurfonluu / fftpack

FFTPack aims to provide an easily usable package of functions using FFTPack library (Fortran 77).

FFTPack

FFTPack aims to provide an easily usable package of functions using FFTPack library (Fortran 77).

Two libraries

This repo contains two libraries:

1. FFTpack library
   Contains FFT functions.
2. Forlab library
   Forlab is a Fortran module that provides a lot of functions for scientific computing mostly inspired by Matlab and Python's package NumPy.

Getting started

git clone https://github.com/zoziha/FFTPack.git
cd FFTPack

Compilation method 1: make & test

Requirements

To build this library you need

• gfortran version > 10 (better or you need to modify the makefile: remove the '-fallow-argument-mismatch' flag)
• gnu make
• terminal bash

make

# executable program
make
make test

# fftpack lib and its includes
make fftpack

When you make this repo, you will get a executable program example_fft.exe in the "./bin" folder, you type make test to run it automatically.

When you type make fftpack, you will get two compiled library files (dynamic and static versions availabe: dll.a/.a) in the "./bin" folder and header files in the "./bin/include" folder. That you can distribute them (fftpack and forlab libraries).

Compilation method 2: fpm

Requirements

To build this library you need

• gfortran
• fpm

To use fftpack within your fpm project, add the following to fpm.toml file:

[dependencies]
fftpack = {git = "https://github.com/keurfonluu/FFTPack.git" }

Fpm build

# gfortran version < 10
fpm build

# gfortran version > 10
fpm build --flag '-fallow-argument-mismatch' 

According to your gfortran version, select and type the above corresponding command line, you will find your compiled results in the "./build" folder.

Fpm test

# gfortran version < 10
fpm test

# gfortran version > 10
fpm test --flag '-fallow-argument-mismatch' 

According to your gfortran version, select and type the above corresponding command line, you can run the test program.

Or you copy the the executable program example_fft from the "./build" folder to the "./example" folder, then you type ./example_fft to run it linking the "*.bin" files.

example_fft

program example_fft

  use fftpack, only: fft, ifft, czt, conv, xcorr, hilbert, filter, &
                     freq2ind, ind2freq, fftshift, ifftshift
  use forlab, only: disp, ones, loadbin, savebin

  implicit none

  integer(kind = 4) :: i, k
  real(kind = 8) :: toc_time
  real(kind = 8), dimension(:), allocatable :: x, y, w, signal, fsignal
  complex(kind = 8), dimension(:), allocatable :: cfft

  ! 1D Fast Fourier transform
  !===========================
  print *, "1D Fast Fourier transform:"

  x = [ 1., 1., 1., 1., 0., 0., 0., 0., 0. ]

  call disp(fft(x))

  ! 1D Fast Fourier transform using CZT
  !=====================================
  print *; print *, "1D Fast Fourier transform using CZT:"

  call disp(czt(x))

  print *; print *, "1D Inverse Fourier transform:"

  call disp(ifft(fft(x, 10)))

  ! Convolution
  !=============
  print *; print *, "Convolution:"

  call disp(conv(dble([ 1., 2., 3., 4., 5., 6. ]), dble([ 6., 7., 8., 1., 2., 4. ])))

  ! Correlation
  !=============
  print *; print *, "Correlation:"

  call disp(xcorr(dble([ 1., 2., 3., 4., 5., 6. ]), dble([ 6., 7., 8., 1., 2., 4. ])))

  ! Hilbert transform
  !===================
  print *; print *, "Hilbert transform:"

  call disp(hilbert(dble([ 1., 2., 3., 4., 5., 6. ])))

  ! Smooth data using convolution
  !===============================
  print *; print *, "Smooth data using convolution:"

  x = [ -2., 3., 5., -8., 8., 7., -8., -5., 2. ]
  k = 3
  y = conv(dble(x), ones(k))
  y = y(k/2+1:k/2+size(x)) / k

  call disp(y)

  ! Convert frequency to index
  !============================
  print *; print *, "Convert frequency to index:"

  print *, freq2ind(250., 500., 1200)

  ! Convert index to frequency
  !============================
  print *; print *, "Convert index to frequency:"

  print *, ind2freq(600, 500., 1200)

  ! Shift the Fourier transform
  !=============================
  print *; print *, "Shift the Fourier transform:"

  cfft = fft(x, 10)
  cfft = fftshift(cfft)

  call disp(cfft)

  ! Inverse shift the Fourier transform
  !=====================================
  print *; print *, "Inverse shift the Fourier transform:"

  cfft = ifftshift(cfft)

  call disp(cfft)

  ! Filter a signal
  !=================
  print *; print *, "Filter a real seismic signal between 1 and 10 Hz:"

  signal = loadbin("utils/signal.bin")
  fsignal = filter(signal, 100.0d0, 3, dble([ 1., 10. ]), 2, dble(0.5))

  call system("rm -rf utils/fsignal.bin")
  call savebin("utils/fsignal.bin", fsignal)
  print *, "Filtered signal saved in utils/fsignal.bin"

  print *
  stop
end program example_fft

Link

keurfonluu/FFTPack
keurfonluu/Forlab
NCAR/ncl#123

fftpack's Issues

[fftpack with gfortran10] the makefile needs to be updated.

Regarding parameter matching, gfortran10 has changed its characteristics, and the makefile needs to be updated.
Need to add a flag: --fallow-argument-mismatch
ref:

1. NCAR/ncl#123
2. https://gcc.gnu.org/gcc-10/changes.html