How to use FFTW: Difference between revisions

Latest revision as of 07:58, 10 March 2017

Getting Started

Note that this is done on an Ubuntu operating system, on Windows some steps are different.

Step 1: Download FFTW from http://www.fftw.org/download.html

Step 2: Extract and Configure it (my path: /home/jafarabadi/Documents/fftw-3.3.4)

cd /home/jafarabadi/Documents/fftw-3.3.4
./configure
make
make install

Alternatively install fftw through your package manager (e.g. pacman -Sy fftw)

Step 3: Add library to project: first open [your_project_name].pro file in Qt Creator and add this line:

LIBS += -lfftw3

Step 4: Example

#include <fftw3.h>
int N;

// Set N to the number of complex elements in the input array

fftw_complex *in, *out;
in = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * N);
out = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * N);

// Initialize 'in' with N complex entries

fftw_plan my_plan;
my_plan = fftw_plan_dft_1d(N, in, out, FFTW_FORWARD, FFTW_ESTIMATE);
fftw_execute(my_plan);

// Use 'out' for something

fftw_destroy_plan(my_plan);
fftw_free(in);
fftw_free(out);

// A short tutorial:
// http://www2.math.uu.se/~figueras/Other/text/fftw_tutorial.pdf

@@ Line 1: / Line 1: @@
-[[Category:Learning::HowTo]]
+[[Category:HowTo]]
+== Getting Started ==
-= How to compute FFT using FFTW in Qt =
+'''Note that this is done on an Ubuntu operating system, on Windows some steps are different.'''
-== Getting Start ==
+* '''Step 1''': Download FFTW from http://www.fftw.org/download.html
-'''Note that I do this in Ubuntu operating system, in Windows some steps are different.'''
+* '''Step 2''': Extract and Configure it (my path: /home/jafarabadi/Documents/fftw-3.3.4)
-* Step1: Download FFTW ([[http://www.fftw.org/download.html]])
+<pre>
+cd /home/jafarabadi/Documents/fftw-3.3.4
+./configure
+make
+make install
+</pre>
-* Step2: Extract and Configure it (my path: /home/jafarabadi/Documents/fftw-3.3.4)<br /><code>cd /home/jafarabadi/Documents/fftw-3.3.4<br />chmod ''x configure<br />./configure<br />make<br />make install</code>
+* Alternatively install fftw through your package manager (e.g. pacman -Sy fftw)
-<br />* Step 3: Add library to project: first open [your_project_name].pro file in Qt Creator and add this line:<br /><code>LIBS''= -lfftw3<code>
-* Step 4: Example<br /></code>#include &lt;fftw3.h&amp;gt;</code><br /><code>int N;
+* '''Step 3''': Add library to project: first open [your_project_name].pro file in Qt Creator and add this line:
-fftw_complex *in, '''out;<br />in = (fftw_complex''') fftw_malloc(sizeof(fftw_complex)'''N);<br />out = (fftw_complex''') fftw_malloc(sizeof(fftw_complex)*N);
+<pre>
+LIBS += -lfftw3
+</pre>
-fftw_plan my_plan;<br />my_plan = fftw_plan_dft_1d(N, in, out, FFTW_FORWARD, FFTW_ESTIMATE);<br />fftw_execute(my_plan);
+* '''Step 4''': Example
-fftw_destroy_plan(my_plan);<br />fftw_free(in);<br />fftw_free(out);
+<code>
+#include <fftw3.h>
+int N;
-// A short tutorial: http://www2.math.uu.se/~figueras/fftw_tutorial/text/fftw_tutorial.pdf</code>
+// Set N to the number of complex elements in the input array
+fftw_complex *in, *out;
+in = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * N);
+out = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * N);
+// Initialize 'in' with N complex entries
+fftw_plan my_plan;
+my_plan = fftw_plan_dft_1d(N, in, out, FFTW_FORWARD, FFTW_ESTIMATE);
+fftw_execute(my_plan);
+// Use 'out' for something
+fftw_destroy_plan(my_plan);
+fftw_free(in);
+fftw_free(out);
+// A short tutorial:
+// http://www2.math.uu.se/~figueras/Other/text/fftw_tutorial.pdf
+</code>

How to use FFTW: Difference between revisions

Latest revision as of 07:58, 10 March 2017

Getting Started

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