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1 /* |
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2 |
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3 Copyright (C) 2004 David Bateman |
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4 Copyright (C) 1996, 1997 John W. Eaton |
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5 |
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6 This file is part of Octave. |
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7 |
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8 Octave is free software; you can redistribute it and/or modify it |
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9 under the terms of the GNU General Public License as published by the |
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10 Free Software Foundation; either version 2, or (at your option) any |
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11 later version. |
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12 |
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13 Octave is distributed in the hope that it will be useful, but WITHOUT |
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14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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16 for more details. |
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17 |
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18 You should have received a copy of the GNU General Public License |
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19 along with Octave; see the file COPYING. If not, write to the Free |
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20 Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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21 02110-1301, USA. |
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22 |
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23 */ |
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24 |
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25 #ifdef HAVE_CONFIG_H |
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26 #include <config.h> |
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27 #endif |
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28 |
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29 #include "lo-mappers.h" |
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30 |
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31 #include "defun-dld.h" |
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32 #include "error.h" |
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33 #include "gripes.h" |
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34 #include "oct-obj.h" |
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35 #include "utils.h" |
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36 |
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37 #if defined (HAVE_FFTW3) |
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38 #define FFTSRC "@sc{Fftw}" |
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39 #else |
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40 #define FFTSRC "@sc{Fftpack}" |
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41 #endif |
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42 |
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43 static octave_value |
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44 do_fft (const octave_value_list &args, const char *fcn, int type) |
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45 { |
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46 octave_value retval; |
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47 |
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48 int nargin = args.length (); |
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49 |
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50 if (nargin < 1 || nargin > 3) |
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51 { |
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52 print_usage (); |
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53 return retval; |
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54 } |
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55 |
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56 octave_value arg = args(0); |
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57 dim_vector dims = arg.dims (); |
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58 octave_idx_type n_points = -1; |
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59 int dim = -1; |
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60 |
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61 if (nargin > 1) |
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62 { |
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63 if (! args(1).is_empty ()) |
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64 { |
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65 double dval = args(1).double_value (); |
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66 if (xisnan (dval)) |
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67 error ("%s: NaN is invalid as the N_POINTS", fcn); |
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68 else |
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69 { |
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70 n_points = NINTbig (dval); |
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71 if (n_points < 0) |
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72 error ("%s: number of points must be greater than zero", fcn); |
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73 } |
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74 } |
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75 } |
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76 |
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77 if (error_state) |
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78 return retval; |
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79 |
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80 if (nargin > 2) |
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81 { |
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82 double dval = args(2).double_value (); |
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83 if (xisnan (dval)) |
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84 error ("%s: NaN is invalid as the N_POINTS", fcn); |
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85 else if (dval < 1 || dval > dims.length ()) |
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86 error ("%s: invalid dimension along which to perform fft", fcn); |
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87 else |
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88 // to be safe, cast it back to int since dim is an int |
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89 dim = NINT (dval) - 1; |
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90 } |
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91 |
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92 if (error_state) |
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93 return retval; |
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94 |
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95 for (octave_idx_type i = 0; i < dims.length (); i++) |
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96 if (dims(i) < 0) |
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97 return retval; |
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98 |
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99 if (dim < 0) |
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100 { |
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101 for (octave_idx_type i = 0; i < dims.length (); i++) |
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102 if (dims(i) > 1) |
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103 { |
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104 dim = i; |
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105 break; |
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106 } |
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107 |
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108 // And if the first argument is scalar? |
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109 if (dim < 0) |
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110 dim = 1; |
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111 } |
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112 |
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113 if (n_points < 0) |
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114 n_points = dims (dim); |
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115 else |
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116 dims (dim) = n_points; |
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117 |
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118 if (dims.any_zero () || n_points == 0) |
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119 return octave_value (NDArray (dims)); |
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120 |
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121 if (arg.is_real_type ()) |
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122 { |
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123 NDArray nda = arg.array_value (); |
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124 |
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125 if (! error_state) |
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126 { |
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127 nda.resize (dims, 0.0); |
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128 retval = (type != 0 ? nda.ifourier (dim) : nda.fourier (dim)); |
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129 } |
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130 } |
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131 else if (arg.is_complex_type ()) |
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132 { |
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133 ComplexNDArray cnda = arg.complex_array_value (); |
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134 |
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135 if (! error_state) |
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136 { |
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137 cnda.resize (dims, 0.0); |
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138 retval = (type != 0 ? cnda.ifourier (dim) : cnda.fourier (dim)); |
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139 } |
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140 } |
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141 else |
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142 { |
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143 gripe_wrong_type_arg (fcn, arg); |
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144 } |
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145 |
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146 return retval; |
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147 } |
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148 |
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149 /* |
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150 |
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151 %!error(fft()) |
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152 %!assert(fft([]), []) |
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153 %!assert(fft(zeros(10,0)), zeros(10,0)) |
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154 %!assert(fft(zeros(0,10)), zeros(0,10)) |
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155 %!assert(fft(0), 0) |
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156 %!assert(fft(1), 1) |
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157 %!assert(fft(1), 1) |
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158 %!assert(fft(ones(2,2)), [2,2; 0,0]) |
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159 %!assert(fft(eye(2,2)), [1,1; 1,-1]) |
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160 |
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161 */ |
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162 |
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163 |
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164 DEFUN_DLD (fft, args, , |
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165 "-*- texinfo -*-\n\ |
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166 @deftypefn {Loadable Function} {} fft (@var{a}, @var{n}, @var{dim})\n\ |
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167 Compute the FFT of @var{a} using subroutines from\n" |
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168 FFTSRC |
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169 ". The FFT is calculated along the first non-singleton dimension of the\n\ |
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170 array. Thus if @var{a} is a matrix, @code{fft (@var{a})} computes the\n\ |
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171 FFT for each column of @var{a}.\n\ |
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172 \n\ |
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173 If called with two arguments, @var{n} is expected to be an integer\n\ |
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174 specifying the number of elements of @var{a} to use, or an empty\n\ |
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175 matrix to specify that its value should be ignored. If @var{n} is\n\ |
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176 larger than the dimension along which the FFT is calculated, then\n\ |
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177 @var{a} is resized and padded with zeros. Otherwise, if @var{n} is\n\ |
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178 smaller than the dimension along which the FFT is calculated, then\n\ |
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179 @var{a} is truncated.\n\ |
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180 \n\ |
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181 If called with three arguments, @var{dim} is an integer specifying the\n\ |
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182 dimension of the matrix along which the FFT is performed\n\ |
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183 @seealso{ifft, fft2, fftn, fftw}\n\ |
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184 @end deftypefn") |
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185 { |
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186 return do_fft (args, "fft", 0); |
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187 } |
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188 |
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189 |
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190 DEFUN_DLD (ifft, args, , |
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191 "-*- texinfo -*-\n\ |
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192 @deftypefn {Loadable Function} {} ifft (@var{a}, @var{n}, @var{dim})\n\ |
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193 Compute the inverse FFT of @var{a} using subroutines from\n" |
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194 FFTSRC |
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195 ". The inverse FFT is calculated along the first non-singleton dimension\n\ |
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196 of the array. Thus if @var{a} is a matrix, @code{fft (@var{a})} computes\n\ |
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197 the inverse FFT for each column of @var{a}.\n\ |
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198 \n\ |
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199 If called with two arguments, @var{n} is expected to be an integer\n\ |
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200 specifying the number of elements of @var{a} to use, or an empty\n\ |
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201 matrix to specify that its value should be ignored. If @var{n} is\n\ |
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202 larger than the dimension along which the inverse FFT is calculated, then\n\ |
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203 @var{a} is resized and padded with zeros. Otherwise, if@var{n} is\n\ |
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204 smaller than the dimension along which the inverse FFT is calculated,\n\ |
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205 then @var{a} is truncated.\n\ |
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206 \n\ |
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207 If called with three agruments, @var{dim} is an integer specifying the\n\ |
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208 dimension of the matrix along which the inverse FFT is performed\n\ |
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209 @seealso{fft, ifft2, ifftn, fftw}\n\ |
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210 @end deftypefn") |
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211 { |
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212 return do_fft (args, "ifft", 1); |
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213 } |
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214 |
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215 /* |
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216 ;;; Local Variables: *** |
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217 ;;; mode: C++ *** |
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218 ;;; End: *** |
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219 */ |
