fftwaff.h 7.85 KB
 thomas.forbriger committed Oct 23, 2015 1 2 3 4 5 6 7 8 9 10 11 12 13 /*! \file fftwaff.h * \brief use fftw together with aff containers (prototypes) * * ---------------------------------------------------------------------------- * * \author Thomas Forbriger * \date 11/07/2006 * * use fftw together with aff containers (prototypes) * * link with -lrfftw -lfftw -lm -laff * * ----  thomas.forbriger committed Oct 23, 2015 14  * libfourier is free software; you can redistribute it and/or modify  thomas.forbriger committed Oct 23, 2015 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208  * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program 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 this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * ---- * * * Copyright (c) 2006 by Thomas Forbriger (BFO Schiltach) * * REVISIONS and CHANGES * - 11/07/2006 V1.0 Thomas Forbriger * - 12/09/2007 V1.1 first running version * - 07/10/2010 V1.2 * - migrate to FFTW3: * - use different fftw header file (fftw3.h) * - type of FFTW plan has changed * - 02/10/2012 V1.3 * - provide size calculation functions * * Migration to FFTW3: * - The location of the arrays in memory are part of the plan. * Consequently we have to either create a new plan for each transform or to * allocate the working array together with the plan and keep it available in * the background. The solution of choice is to keep arrays. We will * introduce a control parameter to the arguments of the constructor which * optionally allows to get rid of the arrays after each transformation. * - FFTW3 uses wisdom by default. * \code * void fftw_forget_wisdom(void); * \endcode * should be called by the destructor of the class. Alternatively * \code * void fftw_cleanup(void); * \endcode * could be called which apparently is even more rigorous. Plans, however, * must be destroyed prior to calling \c fftw_cleanup. * - The FFTW documentation states: * To the extent that this is true, if you have a variable * \code * complex *x, * \endcode * you can pass it directly to FFTW via * \code * reinterpret_cast(x). * \endcode * * ============================================================================ */ // include guard #ifndef TF_FFTWAFF_H_VERSION #define TF_FFTWAFF_H_VERSION \ "TF_FFTWAFF_H V1.3" #include #ifdef FFTWFALLBACK #include #else #include #endif #include namespace fourier { /*! All Fourier transform stuff is collected here. */ namespace fft { /*! A rigid class to do simple transforms using libdrfftw.a. * * uses real double arrays * * How to use this class: * * You may create one instance of this class and use it to transform * several signals in both directions in turn. The class itself takes care * of the transform size and creates a new plan if necessary. FFTs are * invoked by the bracket operators. You should use the class object like * a function. The scaling operators (taking the sampling interval as one * of their arguments) return a series or spectrum scaled appropriately to * match the values of samples from the corresponding Fourier integral * transform (usual convention with \f$dt\f$ and \f$df\f$ * integrals - not \f$d \omega\f$). * * \note * The appropriate number of samples for the time series obtained from a * given set of Fourier coefficients is non-unique, if only the Fourier * coefficients for positive frequencies are given, as is the case here. * A time series with \f$2n\f$ samples and a time series with \f$2n+1\f$ * samples both will results in a set of \f$n+1\f$ Fourier coefficients. * The method to determine the required number of time samples from the * imaginary part of the Nyquist Fourier coefficients only works if the * Nyquist coefficient (at least real part) is finite - which is not the * case for most of our signals. This way we will obtain \f$n+1\f$ Fourier * coefficients from \f$2n\f$ time series samples. When reconstructing the * time series, we will obtain \f$2n+1\f$ samples with a sampling interval * now being \f$2n/(2n+1)\f$ of the original interval. For this reason it * is appropriate to set the size of the expected time series explicitely * either by using the constructor * DRFFTWAFF::DRFFTWAFF(const unsigned int& n) or by * calling DRFFTWAFF::size(const unsigned int& s) prior to * DRFFTWAFF::operator()(const Tspectrum::Tcoc& s). * * \sa \ref page_fftw3 */ class DRFFTWAFF { public: typedef double Tsample; typedef std::complex Tcoeff; typedef aff::Series Tseries; typedef aff::Series Tspectrum; #ifdef FFTWFALLBACK DRFFTWAFF(const unsigned int& n): Msize(n), Mplan_forward(0), Mplan_backward(0) { } DRFFTWAFF(): Msize(0), Mplan_forward(0), Mplan_backward(0) { } #else DRFFTWAFF(const unsigned int& n, const bool& deletearrays=false): Msize(n), Mplan_forward(0), Mplan_backward(0), Mseriesarray(0), Mspectrumarray(0), Mdeletearrays(deletearrays) { } DRFFTWAFF(const bool& deletearrays=false): Msize(0), Mplan_forward(0), Mplan_backward(0), Mseriesarray(0), Mspectrumarray(0), Mdeletearrays(deletearrays) { } #endif ~DRFFTWAFF(); Tspectrum operator()(const Tseries::Tcoc& s, const bool& debug=false) const; Tseries operator()(const Tspectrum::Tcoc& s, const bool& debug=false) const; Tspectrum operator()(const Tseries::Tcoc& s, const Tsample& dt, const bool& debug=false) const; Tseries operator()(const Tspectrum::Tcoc& s, const Tsample& dt, const bool& debug=false) const; Tsample scale_series(const Tsample& dt) const; Tsample scale_spectrum(const Tsample& dt) const; unsigned int size() const { return(Msize); } void size(const unsigned int& s) const { this->set_size(s); } //! return number of coefficients for given number of samples inline static unsigned int spectrumsize(const unsigned int& n) { return(n/2+1); } //! return number of samples for given number of coefficients inline static unsigned int seriessize(const unsigned int& n) { return(n*2-1); } private: void create_plan_forward() const; void create_plan_backward() const; void delete_plans() const; #ifndef FFTWFALLBACK void create_arrays() const; void delete_arrays() const; unsigned int ssize() const { return(DRFFTWAFF::spectrumsize(this->size())); } #endif void set_size(const unsigned int& n) const; mutable unsigned int Msize; #ifdef FFTWFALLBACK mutable rfftw_plan Mplan_forward; mutable rfftw_plan Mplan_backward; #else mutable fftw_plan Mplan_forward; mutable fftw_plan Mplan_backward; mutable double *Mseriesarray; mutable fftw_complex *Mspectrumarray; mutable Tspectrum Mspectrum; mutable Tseries Mseries; bool Mdeletearrays; #endif }; // class DRFFTWAFF } // namespace ftt } // namespace fourier #endif // TF_FFTWAFF_H_VERSION (includeguard) /* ----- END OF fftwaff.h ----- */