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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 | } |