| 1 | use std::f32::{self, consts}; |
| 2 | use std::ops::{Not, Neg, Add, AddAssign, Sub, SubAssign, Mul, MulAssign}; |
| 3 | use std::fmt; |
| 4 | |
| 5 | #[repr(C)] |
| 6 | #[derive(Debug,Clone,Copy,PartialEq)] |
| 7 | pub struct FFTComplex { |
| 8 | pub re: f32, |
| 9 | pub im: f32, |
| 10 | } |
| 11 | |
| 12 | impl FFTComplex { |
| 13 | pub fn exp(val: f32) -> Self { |
| 14 | FFTComplex { re: val.cos(), im: val.sin() } |
| 15 | } |
| 16 | pub fn rotate(self) -> Self { |
| 17 | FFTComplex { re: -self.im, im: self.re } |
| 18 | } |
| 19 | pub fn scale(self, scale: f32) -> Self { |
| 20 | FFTComplex { re: self.re * scale, im: self.im * scale } |
| 21 | } |
| 22 | } |
| 23 | |
| 24 | impl Neg for FFTComplex { |
| 25 | type Output = FFTComplex; |
| 26 | fn neg(self) -> Self::Output { |
| 27 | FFTComplex { re: -self.re, im: -self.im } |
| 28 | } |
| 29 | } |
| 30 | |
| 31 | impl Not for FFTComplex { |
| 32 | type Output = FFTComplex; |
| 33 | fn not(self) -> Self::Output { |
| 34 | FFTComplex { re: self.re, im: -self.im } |
| 35 | } |
| 36 | } |
| 37 | |
| 38 | impl Add for FFTComplex { |
| 39 | type Output = FFTComplex; |
| 40 | fn add(self, other: Self) -> Self::Output { |
| 41 | FFTComplex { re: self.re + other.re, im: self.im + other.im } |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | impl AddAssign for FFTComplex { |
| 46 | fn add_assign(&mut self, other: Self) { |
| 47 | self.re += other.re; |
| 48 | self.im += other.im; |
| 49 | } |
| 50 | } |
| 51 | |
| 52 | impl Sub for FFTComplex { |
| 53 | type Output = FFTComplex; |
| 54 | fn sub(self, other: Self) -> Self::Output { |
| 55 | FFTComplex { re: self.re - other.re, im: self.im - other.im } |
| 56 | } |
| 57 | } |
| 58 | |
| 59 | impl SubAssign for FFTComplex { |
| 60 | fn sub_assign(&mut self, other: Self) { |
| 61 | self.re -= other.re; |
| 62 | self.im -= other.im; |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | impl Mul for FFTComplex { |
| 67 | type Output = FFTComplex; |
| 68 | fn mul(self, other: Self) -> Self::Output { |
| 69 | FFTComplex { re: self.re * other.re - self.im * other.im, |
| 70 | im: self.im * other.re + self.re * other.im } |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | impl MulAssign for FFTComplex { |
| 75 | fn mul_assign(&mut self, other: Self) { |
| 76 | let re = self.re * other.re - self.im * other.im; |
| 77 | let im = self.im * other.re + self.re * other.im; |
| 78 | self.re = re; |
| 79 | self.im = im; |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | impl fmt::Display for FFTComplex { |
| 84 | fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| 85 | write!(f, "({}, {})", self.re, self.im) |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | pub const FFTC_ZERO: FFTComplex = FFTComplex { re: 0.0, im: 0.0 }; |
| 90 | |
| 91 | #[derive(Debug,Clone,Copy,PartialEq)] |
| 92 | pub enum FFTMode { |
| 93 | Matrix, |
| 94 | CooleyTukey, |
| 95 | SplitRadix, |
| 96 | } |
| 97 | |
| 98 | pub struct FFT { |
| 99 | table: Vec<FFTComplex>, |
| 100 | perms: Vec<usize>, |
| 101 | swaps: Vec<usize>, |
| 102 | bits: u32, |
| 103 | mode: FFTMode, |
| 104 | } |
| 105 | |
| 106 | impl FFT { |
| 107 | fn do_fft_inplace_ct(&mut self, data: &mut [FFTComplex], bits: u32, forward: bool) { |
| 108 | if bits == 0 { return; } |
| 109 | if bits == 1 { |
| 110 | let sum01 = data[0] + data[1]; |
| 111 | let dif01 = data[0] - data[1]; |
| 112 | data[0] = sum01; |
| 113 | data[1] = dif01; |
| 114 | return; |
| 115 | } |
| 116 | if bits == 2 { |
| 117 | let sum01 = data[0] + data[1]; |
| 118 | let dif01 = data[0] - data[1]; |
| 119 | let sum23 = data[2] + data[3]; |
| 120 | let dif23 = data[2] - data[3]; |
| 121 | if forward { |
| 122 | data[0] = sum01 + sum23; |
| 123 | data[1] = dif01 - dif23.rotate(); |
| 124 | data[2] = sum01 - sum23; |
| 125 | data[3] = dif01 + dif23.rotate(); |
| 126 | } else { |
| 127 | data[0] = sum01 + sum23; |
| 128 | data[1] = dif01 + dif23.rotate(); |
| 129 | data[2] = sum01 - sum23; |
| 130 | data[3] = dif01 - dif23.rotate(); |
| 131 | } |
| 132 | return; |
| 133 | } |
| 134 | |
| 135 | let hsize = (1 << (bits - 1)) as usize; |
| 136 | self.do_fft_inplace_ct(&mut data[0..hsize], bits - 1, forward); |
| 137 | self.do_fft_inplace_ct(&mut data[hsize..], bits - 1, forward); |
| 138 | let offs = hsize; |
| 139 | { |
| 140 | let e = data[0]; |
| 141 | let o = data[hsize]; |
| 142 | data[0] = e + o; |
| 143 | data[hsize] = e - o; |
| 144 | } |
| 145 | if forward { |
| 146 | for k in 1..hsize { |
| 147 | let e = data[k]; |
| 148 | let o = data[k + hsize] * self.table[offs + k]; |
| 149 | data[k] = e + o; |
| 150 | data[k + hsize] = e - o; |
| 151 | } |
| 152 | } else { |
| 153 | for k in 1..hsize { |
| 154 | let e = data[k]; |
| 155 | let o = data[k + hsize] * !self.table[offs + k]; |
| 156 | data[k] = e + o; |
| 157 | data[k + hsize] = e - o; |
| 158 | } |
| 159 | } |
| 160 | } |
| 161 | |
| 162 | fn do_fft_inplace_splitradix(&mut self, data: &mut [FFTComplex], bits: u32, forward: bool) { |
| 163 | if bits == 0 { return; } |
| 164 | if bits == 1 { |
| 165 | let sum01 = data[0] + data[1]; |
| 166 | let dif01 = data[0] - data[1]; |
| 167 | data[0] = sum01; |
| 168 | data[1] = dif01; |
| 169 | return; |
| 170 | } |
| 171 | if bits == 2 { |
| 172 | let sum01 = data[0] + data[2]; |
| 173 | let dif01 = data[0] - data[2]; |
| 174 | let sum23 = data[1] + data[3]; |
| 175 | let dif23 = data[1] - data[3]; |
| 176 | if forward { |
| 177 | data[0] = sum01 + sum23; |
| 178 | data[1] = dif01 - dif23.rotate(); |
| 179 | data[2] = sum01 - sum23; |
| 180 | data[3] = dif01 + dif23.rotate(); |
| 181 | } else { |
| 182 | data[0] = sum01 + sum23; |
| 183 | data[1] = dif01 + dif23.rotate(); |
| 184 | data[2] = sum01 - sum23; |
| 185 | data[3] = dif01 - dif23.rotate(); |
| 186 | } |
| 187 | return; |
| 188 | } |
| 189 | let qsize = (1 << (bits - 2)) as usize; |
| 190 | let hsize = (1 << (bits - 1)) as usize; |
| 191 | let q3size = qsize + hsize; |
| 192 | |
| 193 | self.do_fft_inplace_splitradix(&mut data[0 ..hsize], bits - 1, forward); |
| 194 | self.do_fft_inplace_splitradix(&mut data[hsize ..q3size], bits - 2, forward); |
| 195 | self.do_fft_inplace_splitradix(&mut data[q3size..], bits - 2, forward); |
| 196 | let off = hsize; |
| 197 | if forward { |
| 198 | { |
| 199 | let t3 = data[0 + hsize] + data[0 + q3size]; |
| 200 | let t4 = (data[0 + hsize] - data[0 + q3size]).rotate(); |
| 201 | let e1 = data[0]; |
| 202 | let e2 = data[0 + qsize]; |
| 203 | data[0] = e1 + t3; |
| 204 | data[0 + qsize] = e2 - t4; |
| 205 | data[0 + hsize] = e1 - t3; |
| 206 | data[0 + q3size] = e2 + t4; |
| 207 | } |
| 208 | for k in 1..qsize { |
| 209 | let t1 = self.table[off + k * 2 + 0] * data[k + hsize]; |
| 210 | let t2 = self.table[off + k * 2 + 1] * data[k + q3size]; |
| 211 | let t3 = t1 + t2; |
| 212 | let t4 = (t1 - t2).rotate(); |
| 213 | let e1 = data[k]; |
| 214 | let e2 = data[k + qsize]; |
| 215 | data[k] = e1 + t3; |
| 216 | data[k + qsize] = e2 - t4; |
| 217 | data[k + hsize] = e1 - t3; |
| 218 | data[k + qsize * 3] = e2 + t4; |
| 219 | } |
| 220 | } else { |
| 221 | { |
| 222 | let t3 = data[0 + hsize] + data[0 + q3size]; |
| 223 | let t4 = (data[0 + hsize] - data[0 + q3size]).rotate(); |
| 224 | let e1 = data[0]; |
| 225 | let e2 = data[0 + qsize]; |
| 226 | data[0] = e1 + t3; |
| 227 | data[0 + qsize] = e2 + t4; |
| 228 | data[0 + hsize] = e1 - t3; |
| 229 | data[0 + q3size] = e2 - t4; |
| 230 | } |
| 231 | for k in 1..qsize { |
| 232 | let t1 = !self.table[off + k * 2 + 0] * data[k + hsize]; |
| 233 | let t2 = !self.table[off + k * 2 + 1] * data[k + q3size]; |
| 234 | let t3 = t1 + t2; |
| 235 | let t4 = (t1 - t2).rotate(); |
| 236 | let e1 = data[k]; |
| 237 | let e2 = data[k + qsize]; |
| 238 | data[k] = e1 + t3; |
| 239 | data[k + qsize] = e2 + t4; |
| 240 | data[k + hsize] = e1 - t3; |
| 241 | data[k + qsize * 3] = e2 - t4; |
| 242 | } |
| 243 | } |
| 244 | } |
| 245 | |
| 246 | pub fn do_fft(&mut self, src: &[FFTComplex], dst: &mut [FFTComplex], forward: bool) { |
| 247 | match self.mode { |
| 248 | FFTMode::Matrix => { |
| 249 | let base = if forward { -consts::PI * 2.0 / (src.len() as f32) } |
| 250 | else { consts::PI * 2.0 / (src.len() as f32) }; |
| 251 | for k in 0..src.len() { |
| 252 | let mut sum = FFTC_ZERO; |
| 253 | for n in 0..src.len() { |
| 254 | let w = FFTComplex::exp(base * ((n * k) as f32)); |
| 255 | sum += src[n] * w; |
| 256 | } |
| 257 | dst[k] = sum; |
| 258 | } |
| 259 | }, |
| 260 | FFTMode::CooleyTukey => { |
| 261 | let bits = self.bits; |
| 262 | for k in 0..src.len() { dst[k] = src[self.perms[k]]; } |
| 263 | self.do_fft_inplace_ct(dst, bits, forward); |
| 264 | }, |
| 265 | FFTMode::SplitRadix => { |
| 266 | let bits = self.bits; |
| 267 | for k in 0..src.len() { dst[k] = src[self.perms[k]]; } |
| 268 | self.do_fft_inplace_splitradix(dst, bits, forward); |
| 269 | }, |
| 270 | }; |
| 271 | } |
| 272 | |
| 273 | pub fn do_fft_inplace(&mut self, data: &mut [FFTComplex], forward: bool) { |
| 274 | for idx in 0..self.swaps.len() { |
| 275 | let nidx = self.swaps[idx]; |
| 276 | if idx != nidx { |
| 277 | let t = data[nidx]; |
| 278 | data[nidx] = data[idx]; |
| 279 | data[idx] = t; |
| 280 | } |
| 281 | } |
| 282 | match self.mode { |
| 283 | FFTMode::Matrix => { |
| 284 | let size = (1 << self.bits) as usize; |
| 285 | let base = if forward { -consts::PI * 2.0 / (size as f32) } |
| 286 | else { consts::PI * 2.0 / (size as f32) }; |
| 287 | let mut res: Vec<FFTComplex> = Vec::with_capacity(size); |
| 288 | for k in 0..size { |
| 289 | let mut sum = FFTC_ZERO; |
| 290 | for n in 0..size { |
| 291 | let w = FFTComplex::exp(base * ((n * k) as f32)); |
| 292 | sum += data[n] * w; |
| 293 | } |
| 294 | res.push(sum); |
| 295 | } |
| 296 | for k in 0..size { |
| 297 | data[k] = res[k]; |
| 298 | } |
| 299 | }, |
| 300 | FFTMode::CooleyTukey => { |
| 301 | let bits = self.bits; |
| 302 | self.do_fft_inplace_ct(data, bits, forward); |
| 303 | }, |
| 304 | FFTMode::SplitRadix => { |
| 305 | let bits = self.bits; |
| 306 | self.do_fft_inplace_splitradix(data, bits, forward); |
| 307 | }, |
| 308 | }; |
| 309 | } |
| 310 | } |
| 311 | |
| 312 | pub struct FFTBuilder { |
| 313 | } |
| 314 | |
| 315 | fn reverse_bits(inval: u32) -> u32 { |
| 316 | const REV_TAB: [u8; 16] = [ |
| 317 | 0b0000, 0b1000, 0b0100, 0b1100, 0b0010, 0b1010, 0b0110, 0b1110, |
| 318 | 0b0001, 0b1001, 0b0101, 0b1101, 0b0011, 0b1011, 0b0111, 0b1111, |
| 319 | ]; |
| 320 | |
| 321 | let mut ret = 0; |
| 322 | let mut val = inval; |
| 323 | for _ in 0..8 { |
| 324 | ret = (ret << 4) | (REV_TAB[(val & 0xF) as usize] as u32); |
| 325 | val = val >> 4; |
| 326 | } |
| 327 | ret |
| 328 | } |
| 329 | |
| 330 | fn swp_idx(idx: usize, bits: u32) -> usize { |
| 331 | let s = reverse_bits(idx as u32) as usize; |
| 332 | s >> (32 - bits) |
| 333 | } |
| 334 | |
| 335 | fn gen_sr_perms(swaps: &mut [usize], size: usize) { |
| 336 | if size <= 4 { return; } |
| 337 | let mut evec: Vec<usize> = Vec::with_capacity(size / 2); |
| 338 | let mut ovec1: Vec<usize> = Vec::with_capacity(size / 4); |
| 339 | let mut ovec2: Vec<usize> = Vec::with_capacity(size / 4); |
| 340 | for k in 0..size/4 { |
| 341 | evec.push (swaps[k * 4 + 0]); |
| 342 | ovec1.push(swaps[k * 4 + 1]); |
| 343 | evec.push (swaps[k * 4 + 2]); |
| 344 | ovec2.push(swaps[k * 4 + 3]); |
| 345 | } |
| 346 | for k in 0..size/2 { swaps[k] = evec[k]; } |
| 347 | for k in 0..size/4 { swaps[k + size/2] = ovec1[k]; } |
| 348 | for k in 0..size/4 { swaps[k + 3*size/4] = ovec2[k]; } |
| 349 | gen_sr_perms(&mut swaps[0..size/2], size/2); |
| 350 | gen_sr_perms(&mut swaps[size/2..3*size/4], size/4); |
| 351 | gen_sr_perms(&mut swaps[3*size/4..], size/4); |
| 352 | } |
| 353 | |
| 354 | fn gen_swaps_for_perm(swaps: &mut Vec<usize>, perms: &Vec<usize>) { |
| 355 | let mut idx_arr: Vec<usize> = Vec::with_capacity(perms.len()); |
| 356 | for i in 0..perms.len() { idx_arr.push(i); } |
| 357 | let mut run_size = 0; |
| 358 | let mut run_pos = 0; |
| 359 | for idx in 0..perms.len() { |
| 360 | if perms[idx] == idx_arr[idx] { |
| 361 | if run_size == 0 { run_pos = idx; } |
| 362 | run_size += 1; |
| 363 | } else { |
| 364 | for i in 0..run_size { |
| 365 | swaps.push(run_pos + i); |
| 366 | } |
| 367 | run_size = 0; |
| 368 | let mut spos = idx + 1; |
| 369 | while idx_arr[spos] != perms[idx] { spos += 1; } |
| 370 | idx_arr[spos] = idx_arr[idx]; |
| 371 | idx_arr[idx] = perms[idx]; |
| 372 | swaps.push(spos); |
| 373 | } |
| 374 | } |
| 375 | } |
| 376 | |
| 377 | impl FFTBuilder { |
| 378 | pub fn new_fft(mode: FFTMode, size: usize) -> FFT { |
| 379 | let mut swaps: Vec<usize>; |
| 380 | let mut perms: Vec<usize>; |
| 381 | let mut table: Vec<FFTComplex>; |
| 382 | let bits = 31 - (size as u32).leading_zeros(); |
| 383 | match mode { |
| 384 | FFTMode::Matrix => { |
| 385 | swaps = Vec::new(); |
| 386 | perms = Vec::new(); |
| 387 | table = Vec::new(); |
| 388 | }, |
| 389 | FFTMode::CooleyTukey => { |
| 390 | perms = Vec::with_capacity(size); |
| 391 | for i in 0..size { |
| 392 | perms.push(swp_idx(i, bits)); |
| 393 | } |
| 394 | swaps = Vec::with_capacity(size); |
| 395 | table = Vec::with_capacity(size); |
| 396 | for _ in 0..4 { table.push(FFTC_ZERO); } |
| 397 | for b in 3..(bits+1) { |
| 398 | let hsize = (1 << (b - 1)) as usize; |
| 399 | let base = -consts::PI / (hsize as f32); |
| 400 | for k in 0..hsize { |
| 401 | table.push(FFTComplex::exp(base * (k as f32))); |
| 402 | } |
| 403 | } |
| 404 | }, |
| 405 | FFTMode::SplitRadix => { |
| 406 | perms = Vec::with_capacity(size); |
| 407 | for i in 0..size { |
| 408 | perms.push(i); |
| 409 | } |
| 410 | gen_sr_perms(perms.as_mut_slice(), 1 << bits); |
| 411 | swaps = Vec::with_capacity(size); |
| 412 | table = Vec::with_capacity(size); |
| 413 | for _ in 0..4 { table.push(FFTC_ZERO); } |
| 414 | for b in 3..(bits+1) { |
| 415 | let qsize = (1 << (b - 2)) as usize; |
| 416 | let base = -consts::PI / ((qsize * 2) as f32); |
| 417 | for k in 0..qsize { |
| 418 | table.push(FFTComplex::exp(base * ((k * 1) as f32))); |
| 419 | table.push(FFTComplex::exp(base * ((k * 3) as f32))); |
| 420 | } |
| 421 | } |
| 422 | }, |
| 423 | }; |
| 424 | gen_swaps_for_perm(&mut swaps, &perms); |
| 425 | FFT { mode: mode, swaps: swaps, perms: perms, bits: bits, table: table } |
| 426 | } |
| 427 | } |
| 428 | |
| 429 | pub struct RDFT { |
| 430 | table: Vec<FFTComplex>, |
| 431 | fft: FFT, |
| 432 | fwd: bool, |
| 433 | size: usize, |
| 434 | fwd_fft: bool, |
| 435 | } |
| 436 | |
| 437 | fn crossadd(a: &FFTComplex, b: &FFTComplex) -> FFTComplex { |
| 438 | FFTComplex { re: a.re + b.re, im: a.im - b.im } |
| 439 | } |
| 440 | |
| 441 | impl RDFT { |
| 442 | pub fn do_rdft(&mut self, src: &[FFTComplex], dst: &mut [FFTComplex]) { |
| 443 | dst.copy_from_slice(src); |
| 444 | self.do_rdft_inplace(dst); |
| 445 | } |
| 446 | pub fn do_rdft_inplace(&mut self, buf: &mut [FFTComplex]) { |
| 447 | if !self.fwd { |
| 448 | for n in 0..self.size/2 { |
| 449 | let in0 = buf[n + 1]; |
| 450 | let in1 = buf[self.size - n - 1]; |
| 451 | |
| 452 | let t0 = crossadd(&in0, &in1); |
| 453 | let t1 = FFTComplex { re: in1.im + in0.im, im: in1.re - in0.re }; |
| 454 | let tab = self.table[n]; |
| 455 | let t2 = FFTComplex { re: t1.im * tab.im + t1.re * tab.re, im: t1.im * tab.re - t1.re * tab.im }; |
| 456 | |
| 457 | buf[n + 1] = FFTComplex { re: t0.im - t2.im, im: t0.re - t2.re }; // (t0 - t2).conj().rotate() |
| 458 | buf[self.size - n - 1] = (t0 + t2).rotate(); |
| 459 | } |
| 460 | let a = buf[0].re; |
| 461 | let b = buf[0].im; |
| 462 | buf[0].re = a - b; |
| 463 | buf[0].im = a + b; |
| 464 | } |
| 465 | self.fft.do_fft_inplace(buf, self.fwd_fft); |
| 466 | if self.fwd { |
| 467 | for n in 0..self.size/2 { |
| 468 | let in0 = buf[n + 1]; |
| 469 | let in1 = buf[self.size - n - 1]; |
| 470 | |
| 471 | let t0 = crossadd(&in0, &in1).scale(0.5); |
| 472 | let t1 = FFTComplex { re: in0.im + in1.im, im: in0.re - in1.re }; |
| 473 | let t2 = t1 * self.table[n]; |
| 474 | |
| 475 | buf[n + 1] = crossadd(&t0, &t2); |
| 476 | buf[self.size - n - 1] = FFTComplex { re: t0.re - t2.re, im: -(t0.im + t2.im) }; |
| 477 | } |
| 478 | let a = buf[0].re; |
| 479 | let b = buf[0].im; |
| 480 | buf[0].re = a + b; |
| 481 | buf[0].im = a - b; |
| 482 | } else { |
| 483 | for n in 0..self.size { |
| 484 | buf[n] = FFTComplex{ re: buf[n].im, im: buf[n].re }; |
| 485 | } |
| 486 | } |
| 487 | } |
| 488 | } |
| 489 | |
| 490 | pub struct RDFTBuilder { |
| 491 | } |
| 492 | |
| 493 | impl RDFTBuilder { |
| 494 | pub fn new_rdft(mode: FFTMode, size: usize, forward: bool, forward_fft: bool) -> RDFT { |
| 495 | let mut table: Vec<FFTComplex> = Vec::with_capacity(size / 4); |
| 496 | let (base, scale) = if forward { (consts::PI / (size as f32), 0.5) } else { (-consts::PI / (size as f32), 1.0) }; |
| 497 | for i in 0..size/2 { |
| 498 | table.push(FFTComplex::exp(base * ((i + 1) as f32)).scale(scale)); |
| 499 | } |
| 500 | let fft = FFTBuilder::new_fft(mode, size); |
| 501 | RDFT { table, fft, size, fwd: forward, fwd_fft: forward_fft } |
| 502 | } |
| 503 | } |
| 504 | |
| 505 | |
| 506 | #[cfg(test)] |
| 507 | mod test { |
| 508 | use super::*; |
| 509 | |
| 510 | #[test] |
| 511 | fn test_fft() { |
| 512 | let mut fin: [FFTComplex; 128] = [FFTC_ZERO; 128]; |
| 513 | let mut fout1: [FFTComplex; 128] = [FFTC_ZERO; 128]; |
| 514 | let mut fout2: [FFTComplex; 128] = [FFTC_ZERO; 128]; |
| 515 | let mut fout3: [FFTComplex; 128] = [FFTC_ZERO; 128]; |
| 516 | let mut fft1 = FFTBuilder::new_fft(FFTMode::Matrix, fin.len()); |
| 517 | let mut fft2 = FFTBuilder::new_fft(FFTMode::CooleyTukey, fin.len()); |
| 518 | let mut fft3 = FFTBuilder::new_fft(FFTMode::SplitRadix, fin.len()); |
| 519 | let mut seed: u32 = 42; |
| 520 | for i in 0..fin.len() { |
| 521 | seed = seed.wrapping_mul(1664525).wrapping_add(1013904223); |
| 522 | let val = (seed >> 16) as i16; |
| 523 | fin[i].re = (val as f32) / 256.0; |
| 524 | seed = seed.wrapping_mul(1664525).wrapping_add(1013904223); |
| 525 | let val = (seed >> 16) as i16; |
| 526 | fin[i].im = (val as f32) / 256.0; |
| 527 | } |
| 528 | fft1.do_fft(&fin, &mut fout1, true); |
| 529 | fft2.do_fft(&fin, &mut fout2, true); |
| 530 | fft3.do_fft(&fin, &mut fout3, true); |
| 531 | |
| 532 | for i in 0..fin.len() { |
| 533 | assert!((fout1[i].re - fout2[i].re).abs() < 1.0); |
| 534 | assert!((fout1[i].im - fout2[i].im).abs() < 1.0); |
| 535 | assert!((fout1[i].re - fout3[i].re).abs() < 1.0); |
| 536 | assert!((fout1[i].im - fout3[i].im).abs() < 1.0); |
| 537 | } |
| 538 | fft1.do_fft_inplace(&mut fout1, false); |
| 539 | fft2.do_fft_inplace(&mut fout2, false); |
| 540 | fft3.do_fft_inplace(&mut fout3, false); |
| 541 | |
| 542 | let sc = 1.0 / (fin.len() as f32); |
| 543 | for i in 0..fin.len() { |
| 544 | assert!((fin[i].re - fout1[i].re * sc).abs() < 1.0); |
| 545 | assert!((fin[i].im - fout1[i].im * sc).abs() < 1.0); |
| 546 | assert!((fout1[i].re - fout2[i].re).abs() < 1.0); |
| 547 | assert!((fout1[i].im - fout2[i].im).abs() < 1.0); |
| 548 | assert!((fout1[i].re - fout3[i].re).abs() < 1.0); |
| 549 | assert!((fout1[i].im - fout3[i].im).abs() < 1.0); |
| 550 | } |
| 551 | } |
| 552 | |
| 553 | #[test] |
| 554 | fn test_rdft() { |
| 555 | let mut fin: [FFTComplex; 128] = [FFTC_ZERO; 128]; |
| 556 | let mut fout1: [FFTComplex; 128] = [FFTC_ZERO; 128]; |
| 557 | let mut rdft = RDFTBuilder::new_rdft(FFTMode::SplitRadix, fin.len(), true, true); |
| 558 | let mut seed: u32 = 42; |
| 559 | for i in 0..fin.len() { |
| 560 | seed = seed.wrapping_mul(1664525).wrapping_add(1013904223); |
| 561 | let val = (seed >> 16) as i16; |
| 562 | fin[i].re = (val as f32) / 256.0; |
| 563 | seed = seed.wrapping_mul(1664525).wrapping_add(1013904223); |
| 564 | let val = (seed >> 16) as i16; |
| 565 | fin[i].im = (val as f32) / 256.0; |
| 566 | } |
| 567 | rdft.do_rdft(&fin, &mut fout1); |
| 568 | let mut irdft = RDFTBuilder::new_rdft(FFTMode::SplitRadix, fin.len(), false, true); |
| 569 | irdft.do_rdft_inplace(&mut fout1); |
| 570 | |
| 571 | for i in 0..fin.len() { |
| 572 | let tst = fout1[i].scale(0.5/(fout1.len() as f32)); |
| 573 | assert!((tst.re - fin[i].re).abs() < 1.0); |
| 574 | assert!((tst.im - fin[i].im).abs() < 1.0); |
| 575 | } |
| 576 | } |
| 577 | } |