[301] | 1 | // ----------------------------------------------------------------------- |
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| 2 | // Hanning.cc: Member functions for the Hanning class. |
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| 3 | // ----------------------------------------------------------------------- |
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| 4 | // Copyright (C) 2006, Matthew Whiting, ATNF |
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| 5 | // |
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| 6 | // This program is free software; you can redistribute it and/or modify it |
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| 7 | // under the terms of the GNU General Public License as published by the |
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| 8 | // Free Software Foundation; either version 2 of the License, or (at your |
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| 9 | // option) any later version. |
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| 10 | // |
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| 11 | // Duchamp is distributed in the hope that it will be useful, but WITHOUT |
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| 12 | // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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| 13 | // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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| 14 | // for more details. |
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| 15 | // |
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| 16 | // You should have received a copy of the GNU General Public License |
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| 17 | // along with Duchamp; if not, write to the Free Software Foundation, |
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| 18 | // Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA |
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| 19 | // |
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| 20 | // Correspondence concerning Duchamp may be directed to: |
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| 21 | // Internet email: Matthew.Whiting [at] atnf.csiro.au |
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| 22 | // Postal address: Dr. Matthew Whiting |
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| 23 | // Australia Telescope National Facility, CSIRO |
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| 24 | // PO Box 76 |
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| 25 | // Epping NSW 1710 |
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| 26 | // AUSTRALIA |
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| 27 | // ----------------------------------------------------------------------- |
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[221] | 28 | #include <iostream> |
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| 29 | #include <math.h> |
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[393] | 30 | #include <duchamp/Utils/Hanning.hh> |
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[221] | 31 | |
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| 32 | Hanning::Hanning(){ |
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| 33 | allocated=false; |
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[275] | 34 | } |
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| 35 | |
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[221] | 36 | Hanning::~Hanning(){ |
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| 37 | if(allocated) delete [] coeffs; |
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[275] | 38 | } |
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[221] | 39 | |
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[365] | 40 | Hanning::Hanning(const Hanning& h) |
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| 41 | { |
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| 42 | operator=(h); |
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| 43 | } |
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| 44 | |
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| 45 | Hanning& Hanning::operator=(const Hanning& h) |
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| 46 | { |
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| 47 | if(this==&h) return *this; |
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| 48 | this->hanningSize = h.hanningSize; |
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| 49 | this->allocated = h.allocated; |
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| 50 | if(h.allocated){ |
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| 51 | this->coeffs = new float[this->hanningSize]; |
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| 52 | for(int i=0;i<h.hanningSize;i++) this->coeffs[i] = h.coeffs[i]; |
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| 53 | } |
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| 54 | return *this; |
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| 55 | } |
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| 56 | |
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[528] | 57 | Hanning::Hanning(int size) |
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| 58 | { |
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| 59 | /// @details |
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| 60 | /// Constructor that sets the Hanning width and calculates the |
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| 61 | /// coefficients. Does this by simply calling the |
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| 62 | /// Hanning::define(int) function. |
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| 63 | /// \param size The full width of the filter. The parameter \f$a\f$ |
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| 64 | /// is defined as (size+1)/2. |
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[275] | 65 | |
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| 66 | this->allocated=false; |
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| 67 | this->define(size); |
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[419] | 68 | } |
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[275] | 69 | |
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| 70 | void Hanning::define(int size) |
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| 71 | { |
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[528] | 72 | /// @details |
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| 73 | /// Function that sets the Hanning width and calculates the coefficients. |
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| 74 | /// \param size The full width of the filter. The parameter \f$a\f$ is |
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| 75 | /// defined as (size+1)/2. |
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| 76 | |
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[221] | 77 | if(size%2==0){ |
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| 78 | std::cerr << "Hanning: need an odd number for the size. " |
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[365] | 79 | << "Changing "<< size << " to " << size+1<<".\n"; |
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| 80 | size++; |
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[221] | 81 | } |
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[275] | 82 | this->hanningSize = size; |
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| 83 | if(this->allocated) delete [] this->coeffs; |
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| 84 | this->coeffs = new float[size]; |
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| 85 | this->allocated = true; |
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[221] | 86 | float a = (size+1.)/2.; |
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| 87 | for(int i=0;i<size;i++){ |
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| 88 | float x = i-(size-1)/2.; |
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[275] | 89 | this->coeffs[i] = 0.5 + 0.5*cos(x * M_PI / a); |
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[221] | 90 | } |
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[275] | 91 | } |
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[221] | 92 | |
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| 93 | |
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[275] | 94 | |
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[528] | 95 | float *Hanning::smooth(float *array, int npts) |
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| 96 | { |
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| 97 | /// @details |
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| 98 | /// This smooths an array of float by doing a discrete convolution of |
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| 99 | /// the input array with the filter coefficients. |
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| 100 | /// |
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| 101 | /// Currently only works for C arrays of floats, as that is all I |
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| 102 | /// need it for. Could be made more general if needs be. |
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| 103 | /// |
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| 104 | /// \param array The input array. Needs to be defined -- no memory |
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| 105 | /// checks are done! |
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| 106 | /// \param npts The size of the input array. |
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| 107 | /// \return Returns an array of the same size. If filter coefficients |
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| 108 | /// have not been allocated, the input array is returned. |
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| 109 | |
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[221] | 110 | if(!this->allocated) return array; |
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| 111 | else{ |
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| 112 | float *newarray = new float[npts]; |
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| 113 | float scale = (hanningSize+1.)/2.; |
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| 114 | for(int i=0;i<npts;i++){ |
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| 115 | newarray[i] = 0.; |
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| 116 | for(int j=0;j<hanningSize;j++){ |
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| 117 | int x = j-(hanningSize-1)/2; |
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| 118 | if((i+x>0)&&(i+x<npts)) newarray[i]+=coeffs[j] * array[i+x]; |
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| 119 | } |
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| 120 | newarray[i] /= scale; |
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| 121 | } |
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| 122 | return newarray; |
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| 123 | } |
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[275] | 124 | } |
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