FFT with GSL

2025-06-25 02:02:02 +01:00 · 2017-10-10 16:56:23 +01:00
parent 839159831f
commit 6b624186cd
6 changed files with 301 additions and 0 deletions
--- a/utils/sample-ft.cpp
+++ b/utils/sample-ft.cpp
@ -0,0 +1,94 @@
+/*
+ * sample-ft.cpp, part of LatAnalyze 3
+ *
+ * Copyright (C) 2013 - 2016 Antonin Portelli
+ *
+ * LatAnalyze 3 is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * LatAnalyze 3 is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with LatAnalyze 3.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <LatCore/OptParser.hpp>
+#include <LatAnalyze/GslFFT.hpp>
+#include <LatAnalyze/Io.hpp>
+
+using namespace std;
+using namespace Latan;
+
+int main(int argc, char *argv[])
+{
+    // argument parsing ////////////////////////////////////////////////////////
+    OptParser    opt;
+    bool         parsed;
+    string       inFilename, outFilename;
+    unsigned int dir = FFT::Forward;
+    
+    opt.addOption("o", "output", OptParser::OptType::value  , true,
+                  "output file name (default: result not saved)", "");
+    opt.addOption("b", "backward", OptParser::OptType::trigger, true,
+                  "backward Fourier transform (forward by default)");
+    opt.addOption("" , "help"  , OptParser::OptType::trigger, true,
+                  "show this help message and exit");
+    parsed = opt.parse(argc, argv);
+    if (!parsed or (opt.getArgs().size() != 1) or opt.gotOption("help"))
+    {
+        cerr << "usage: " << argv[0];
+        cerr << " <options> <input file>" << endl;
+        cerr << endl << "Possible options:" << endl << opt << endl;
+        
+        return EXIT_FAILURE;
+    }
+    inFilename  = opt.getArgs()[0];
+    outFilename = opt.optionValue("o");
+    if (opt.gotOption("b"))
+    {
+        dir = FFT::Backward;
+    }
+    
+    // Fourier transform ///////////////////////////////////////////////////////
+    DMatSample in          = Io::load<DMatSample>(inFilename);
+    Index      nSample     = in.size(), l = in[central].rows();
+    bool       isInComplex = (in[central].cols() > 1);
+    CMatSample res(nSample, l, 1);
+    DMatSample out(nSample, l, 2);
+    GslFFT     ft(l);
+    
+    cout << "-- computing Fourier transform..." << endl;
+    FOR_STAT_ARRAY(in, s)
+    {
+        res[s].real() = in[s].col(0);
+        if (isInComplex)
+        {
+            res[s].imag() = in[s].col(1);
+        }
+        else
+        {
+            res[s].imag() = DVec::Constant(l, 0.);
+        }
+        ft(res[s], dir);
+        out[s].col(0) = res[s].real();
+        out[s].col(1) = res[s].imag();
+    }
+    
+    // output /////////////////////////////////////////////////////////////////
+    cout << scientific;
+    cout << "central value:\n"      << out[central];
+    cout << endl;
+    cout << "standard deviation:\n" << out.variance().cwiseSqrt();
+    cout << endl;
+    if (!outFilename.empty())
+    {
+        Io::save<DMatSample>(out, outFilename);
+    }
+    
+    return EXIT_SUCCESS;
+}