aboutsummaryrefslogtreecommitdiff
path: root/src/symmetry.c
blob: 65aef98b908797a696c27a4bca912436d411ddf4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
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
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
/*
 * symmetry.c
 *
 * Symmetry stuff
 *
 * (c) 2006-2008 Thomas White <taw27@cam.ac.uk>
 *
 *  synth2d - Two-Dimensional Crystallographic Fourier Synthesis
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <assert.h>

#include "symmetry.h"
#include "reflist.h"
#include "model.h"

#define is_odd(a) ((a)%2==1)

/* Return a list of atoms containing the given atom and all its symmetry equivalents */
AtomicModel *symmetry_generate_equivalent_atoms(AtomicModel *model, size_t j, ModelTarget target) {

	AtomicModel *list;

	list = model_new();
	list->atoms[list->n_atoms] = model->atoms[j];  list->n_atoms++;

	if ( target == MODEL_TARGET_DISPLAY ) {

		if ( model->atoms[j].x == 0 ) {
			list->atoms[list->n_atoms] = model->atoms[j];
			list->atoms[list->n_atoms].x = 1.0;
			list->n_atoms++;
		}

		if ( model->atoms[j].y == 0 ) {
			list->atoms[list->n_atoms] = model->atoms[j];
			list->atoms[list->n_atoms].y = 1.0;
			list->n_atoms++;
		}

		if ( (model->atoms[j].x == 0) && (model->atoms[j].y == 0) ) {
			list->atoms[list->n_atoms] = model->atoms[j];
			list->atoms[list->n_atoms].x = 1.0;
			list->atoms[list->n_atoms].y = 1.0;
			list->n_atoms++;
		}

	}

	if ( model->sym & SYMMETRY_CENTRE ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].x = 1-list->atoms[list->n_atoms].x;
		list->atoms[list->n_atoms].y = 1-list->atoms[list->n_atoms].y;
		list->n_atoms++;
	}

	if ( model->sym & SYMMETRY_MIRROR_HORIZONTAL ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].y = 1-list->atoms[list->n_atoms].y;
		list->n_atoms++;
	}

	if ( model->sym & SYMMETRY_MIRROR_VERTICAL ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].x = 1-list->atoms[list->n_atoms].x;
		list->n_atoms++;
	}

	if ( model->sym & SYMMETRY_GLIDE_HORIZONTAL ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].x = fmod(0.5 + list->atoms[list->n_atoms].x, 1);
		list->atoms[list->n_atoms].y = 1-list->atoms[list->n_atoms].y;
		list->n_atoms++;
	}

	if ( model->sym & SYMMETRY_GLIDE_VERTICAL ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].x = 1-list->atoms[list->n_atoms].x;
		list->atoms[list->n_atoms].y = fmod(0.5 + list->atoms[list->n_atoms].y, 1);
		list->n_atoms++;
	}

	if ( model->sym & SYMMETRY_GLIDE_HORIZONTAL_QUARTER ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].x = fmod(0.5 + list->atoms[list->n_atoms].x, 1);
		list->atoms[list->n_atoms].y = fmod(1.5 - list->atoms[list->n_atoms].y, 1);
		list->n_atoms++;
	}

	if ( model->sym & SYMMETRY_GLIDE_VERTICAL_QUARTER ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].x = fmod(1.5 - list->atoms[list->n_atoms].x, 1);
		list->atoms[list->n_atoms].y = fmod(0.5 + list->atoms[list->n_atoms].y, 1);
		list->n_atoms++;
	}

	/* Fix cm */
	if ( (model->sym & SYMMETRY_GLIDE_HORIZONTAL_QUARTER) && (model->sym & SYMMETRY_MIRROR_HORIZONTAL) ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].x = fmod(0.5 + list->atoms[list->n_atoms].x, 1);
		list->atoms[list->n_atoms].y = 1 - fmod(1.5 - list->atoms[list->n_atoms].y, 1);
		list->n_atoms++;
	} else if ( (model->sym & SYMMETRY_GLIDE_VERTICAL_QUARTER) && (model->sym & SYMMETRY_MIRROR_VERTICAL) ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].x = 1 - fmod(1.5 - list->atoms[list->n_atoms].x, 1);
		list->atoms[list->n_atoms].y = fmod(0.5 + list->atoms[list->n_atoms].y, 1);
		list->n_atoms++;
	}

	/* Fix c2mm */
	if ( (model->sym & SYMMETRY_GLIDE_VERTICAL_QUARTER) && (model->sym & SYMMETRY_MIRROR_HORIZONTAL) ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].x = fmod(1.5 - list->atoms[list->n_atoms].x, 1);
		list->atoms[list->n_atoms].y = 1 - fmod(0.5 + list->atoms[list->n_atoms].y, 1);
		list->n_atoms++;
	}

	if ( model->sym & SYMMETRY_MIRROR_HORIZONTAL_QUARTER ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].x = list->atoms[list->n_atoms].x;
		list->atoms[list->n_atoms].y = fmod(1.5 - list->atoms[list->n_atoms].y, 1);
		list->n_atoms++;
	}

	if ( model->sym & SYMMETRY_MIRROR_VERTICAL_QUARTER ) {
		list->atoms[list->n_atoms] = model->atoms[j];
		list->atoms[list->n_atoms].x = fmod(1.5 - list->atoms[list->n_atoms].x, 1);
		list->atoms[list->n_atoms].y = list->atoms[list->n_atoms].y;
		list->n_atoms++;
	}

	return list;

}

ReflectionList *symmetry_generate_equivalent_reflections(Symmetry sym, signed int h, signed int k, signed int l) {

	ReflectionList *result;

	result = reflist_new();

	/* Remove the minus in front of 'l' to make even HOLZ conditional transforms real.
	 *	This is generally the wrong thing to do. */
	if ( sym & SYMMETRY_FRIEDEL ) reflist_addref_deltatheta(result, -h, -k, -l, 0, -1);

	if ( sym & SYMMETRY_MIRROR_HORIZONTAL ) reflist_addref_deltatheta(result, h, -k, l, 0, 1);
	if ( sym & SYMMETRY_MIRROR_VERTICAL ) reflist_addref_deltatheta(result, -h, k, l, 0, 1);
	if ( sym & SYMMETRY_MIRROR_DIAGONAL ) reflist_addref_deltatheta(result, -h, -k, l, 0, 1);

	if ( sym & SYMMETRY_GLIDE_HORIZONTAL ) reflist_addref_deltatheta(result, h, -k, l, M_PI, 1);
	if ( sym & SYMMETRY_GLIDE_VERTICAL ) reflist_addref_deltatheta(result, -h, k, l, M_PI, 1);

	if ( sym & SYMMETRY_GLIDE_HORIZONTAL_QUARTER ) {
		if ( is_odd(abs(h)+abs(k)) ) {
			reflist_addref_deltatheta(result, h, -k, l, M_PI, 1);
		} else {
			reflist_addref_deltatheta(result, h, -k, l, 0, 1);
		}
	}

	if ( sym & SYMMETRY_GLIDE_VERTICAL_QUARTER ) {
		if ( is_odd(abs(h)+abs(k)) ) {
			reflist_addref_deltatheta(result, -h, k, l, M_PI, 1);
		} else {
			reflist_addref_deltatheta(result, -h, k, l, 0, 1);
		}
	}

	if ( sym & SYMMETRY_ROTATION_4 ) {
		if ( sym & SYMMETRY_GLIDE_DIAGONAL ) {
			if ( is_odd(abs(h)+abs(k)) ) {
				reflist_addref_deltatheta(result, h, -k, l, M_PI, 1);
				reflist_addref_deltatheta(result, -h, k, l, M_PI, 1);
				reflist_addref_deltatheta(result, -h, -k, l, 0, 1);
				reflist_addref_deltatheta(result, k, h, l, 0, 1);
				reflist_addref_deltatheta(result, -k, h, l, M_PI, 1);
				reflist_addref_deltatheta(result, k, -h, l, M_PI, 1);
				reflist_addref_deltatheta(result, -k, -h, l, 0, 1);
			} else {
				reflist_addref_deltatheta(result, h, -k, l, 0, 1);
				reflist_addref_deltatheta(result, -h, k, l, 0, 1);
				reflist_addref_deltatheta(result, -h, -k, l, 0, 1);
				reflist_addref_deltatheta(result, k, h, l, 0, 1);
				reflist_addref_deltatheta(result, -k, h, l, 0, 1);
				reflist_addref_deltatheta(result, k, -h, l, 0, 1);
				reflist_addref_deltatheta(result, -k, -h, l, 0, 1);
			}
		} else {
			reflist_addref_deltatheta(result, -h, -k, l, 0, 1);
			reflist_addref_deltatheta(result, -h, k, l, 0, 1);
			reflist_addref_deltatheta(result, h, -k, l, 0, 1);
		}
	}

	return result;

}

static double symmetry_realphase(double phk) {

	if ( (phk >= 0) && (phk < M_PI_2) ) phk = 0;
	else if ( (phk > M_PI_2) && (phk < M_PI) ) phk = M_PI;
	else if ( (phk < 0) && (phk > -M_PI/2) ) phk = 0;
	else if ( (phk <= -M_PI_2) && (phk > -M_PI) ) phk = M_PI;

	return phk;

}

void symmetry_centricity(ReflectionList *reflections, unsigned int i, Symmetry sym, SymFlags flags) {

	double am, ph;
	signed int h, k;

	ph = 0;
	h = reflections->refs[i].h;
	k = reflections->refs[i].k;

	am = reflections->refs[i].amplitude;
	if ( flags & SYMFLAG_PHASES_KNOWN ) ph = fmod(reflections->refs[i].phase_known, 2*M_PI);
	if ( flags & SYMFLAG_PHASES_CALC ) ph = fmod(reflections->refs[i].phase_calc, 2*M_PI);

	if ( (sym & SYMMETRY_MIRROR_HORIZONTAL) && (sym & SYMMETRY_FRIEDEL) && (h == 0) ) {
		ph = symmetry_realphase(ph);
	}

	if ( (sym & SYMMETRY_MIRROR_VERTICAL) && (sym & SYMMETRY_FRIEDEL) && (k == 0) ) {
		ph = symmetry_realphase(ph);
	}

	if ( (sym & SYMMETRY_CENTRE) && (sym & SYMMETRY_FRIEDEL) ) {
		ph = symmetry_realphase(ph);
	}

	if ((	( (sym & SYMMETRY_GLIDE_HORIZONTAL) && (sym & SYMMETRY_MIRROR_VERTICAL) )
	     || ( (sym & SYMMETRY_GLIDE_HORIZONTAL_QUARTER) && (sym & SYMMETRY_MIRROR_VERTICAL) )
	     || ( (sym & SYMMETRY_GLIDE_VERTICAL) && (sym & SYMMETRY_MIRROR_HORIZONTAL) )
	     || ( (sym & SYMMETRY_GLIDE_VERTICAL_QUARTER) && (sym & SYMMETRY_MIRROR_HORIZONTAL) ) )
	     && (is_odd(abs(h)+abs(k))) ) {
		if ( (ph >= 0) && (ph < M_PI) ) ph = M_PI_2;
		else if ( (ph >= M_PI_2) && (ph < 2*M_PI) ) ph = -M_PI_2;
		else if ( (ph < 0) && (ph > -M_PI) ) ph = -M_PI_2;
		else if ( (ph <= -M_PI) ) ph = M_PI_2;
	}

	if ( flags & SYMFLAG_PHASES_KNOWN ) reflections->refs[i].phase_known = ph;
	if ( flags & SYMFLAG_PHASES_CALC ) reflections->refs[i].phase_calc = ph;

}

unsigned int symmetry_reflection_allowed(signed int h, signed int k, signed int l, Symmetry sym) {

	if ( (sym & SYMMETRY_GLIDE_HORIZONTAL) && (h == 0) && (k % 2) ) return 0;
	if ( (sym & SYMMETRY_GLIDE_HORIZONTAL_QUARTER) && (h == 0) && (k % 2) ) return 0;
	if ( (sym & SYMMETRY_GLIDE_VERTICAL) && (k == 0) && (h % 2) ) return 0;
	if ( (sym & SYMMETRY_GLIDE_VERTICAL_QUARTER) && (k == 0) && (h % 2) ) return 0;
	if ( (sym & SYMMETRY_ROTATION_4 ) && ( sym & SYMMETRY_GLIDE_DIAGONAL ) && (k == 0) && (h % 2) ) return 0;
	if ( (sym & SYMMETRY_ROTATION_4 ) && ( sym & SYMMETRY_GLIDE_DIAGONAL ) && (h == 0) && (k % 2) ) return 0;

	return 1;

}

/* Symmetrise a list of reflections (expanding all equivalents to P1) */
double symmetry_symmetrise(ReflectionList *reflections, Symmetry sym, SymFlags flags) {

	unsigned int i = 0;
	double r_sym = 0;
	double r_sym_norm = 0;
	unsigned int new_ref = 0;
	unsigned int elim_ref = 0;
	double am_elim = 0;
	unsigned int n = reflections->n_reflections;

	for ( i=1; i<n; i++ ) {	/* Don't symmetrise 000 */

		signed int h, k, l;

		h = reflections->refs[i].h;
		k = reflections->refs[i].k;
		l = reflections->refs[i].l;

		if ( (h==0) && (k==0) && (l==0) ) continue;
		if ( symmetry_reflection_allowed(h, k, l, sym) ) {

			double ph = 69;
			unsigned int j;
			double av;
			unsigned int av_n;
			ReflectionList *equivalents;

			equivalents = symmetry_generate_equivalent_reflections(sym, h, k, l);
			symmetry_centricity(reflections, i, sym, flags);

			/* First pass: calculate average amplitude, determine phase */
			av = reflections->refs[i].amplitude; av_n = 1;
			for ( j=1; j<equivalents->n_reflections; j++ ) {
				unsigned int p;
				p = reflist_inlist(reflections, equivalents->refs[j].h, equivalents->refs[j].k, equivalents->refs[j].l);
				if ( p ) {
					av += reflections->refs[p].amplitude;
					av_n++;
				}
			}
			av = av / av_n;
			r_sym += fabs(av - reflections->refs[i].amplitude);
			r_sym_norm += reflections->refs[i].amplitude;
			if ( flags & SYMFLAG_PHASES_KNOWN ) ph = fmod(reflections->refs[i].phase_known, 2*M_PI);
			if ( flags & SYMFLAG_PHASES_CALC ) ph = fmod(reflections->refs[i].phase_calc, 2*M_PI);
			//printf("Phase of %3i %3i %3i is %f\n", h, k, l, ph);

			/* Second pass: set all equivalent reflections to the average amplitude */
			reflections->refs[i].amplitude = av;
			for ( j=1; j<equivalents->n_reflections; j++ ) {

				unsigned int p;
				double phn;
				p = reflist_inlist(reflections, equivalents->refs[j].h, equivalents->refs[j].k, equivalents->refs[j].l);
				if ( p ) {
					r_sym += fabs(av - reflections->refs[p].amplitude);
					r_sym_norm += reflections->refs[p].amplitude;
					reflections->refs[p].amplitude = av;
				} else {
					p = reflist_addref_am(reflections, equivalents->refs[j].h, equivalents->refs[j].k, equivalents->refs[j].l, av);
					//printf("SY: Generating %3i %3i %3i am=%f\n", equivalents->refs[j].h,
					//			equivalents->refs[j].k, equivalents->refs[j].l, av);
					new_ref++;
				}
				phn = (ph + equivalents->refs[j].delta_theta) * equivalents->refs[j].multiplier;
				if ( flags & SYMFLAG_PHASES_KNOWN ) {
					reflections->refs[p].phase_known = phn;
					reflections->refs[p].phase_known_set = 1;
				}
				if ( flags & SYMFLAG_PHASES_CALC ) {
					reflections->refs[p].phase_calc = phn;
					reflections->refs[p].phase_calc_set = 1;
				}
				//printf("Set phase of %3i %3i %3i to %f (dt=%f, mul=%i)\n", equivalents->refs[j].h,
							//equivalents->refs[j].k, equivalents->refs[j].l,
							//phn, equivalents->refs[j].delta_theta, equivalents->refs[j].multiplier);


			}

			reflist_free(equivalents);

		} else {

			am_elim += reflections->refs[i].amplitude;
			reflist_delref(reflections, h, k, l);
			//printf("SY: Eliminating systematically absent reflection %i %i %i\n", h, k, l);
			elim_ref++;
			i--;

		}

	}

	if ( r_sym > 0 ) {
		r_sym = r_sym / r_sym_norm;
	}
	//printf("SY: R_sym = %.2f%%, %i reflections generated, %i reflections eliminated (total amplitude %f)\n", r_sym*100, new_ref, elim_ref, am_elim);

	return r_sym;

}

Symmetry symmetry_encode(const char *symmetry) {

	if ( strcmp(symmetry, "p1") == 0 ) return PLANEGROUP_P1;
	if ( strcmp(symmetry, "p2") == 0 ) return PLANEGROUP_P2;
	if ( strcmp(symmetry, "pm (m // x)") == 0 ) return PLANEGROUP_PM_X;
	if ( strcmp(symmetry, "pm (m // y)") == 0 ) return PLANEGROUP_PM_Y;
	if ( strcmp(symmetry, "pg (g // x)") == 0 ) return PLANEGROUP_PG_X;
	if ( strcmp(symmetry, "pg (g // y)") == 0 ) return PLANEGROUP_PG_Y;
	if ( strcmp(symmetry, "cm (m // x)") == 0 ) return PLANEGROUP_CM_X;
	if ( strcmp(symmetry, "cm (m // y)") == 0 ) return PLANEGROUP_CM_Y;
	if ( strcmp(symmetry, "p2mm") == 0 ) return PLANEGROUP_P2MM;
	if ( strcmp(symmetry, "p2mg (m // x)") == 0 ) return PLANEGROUP_P2MG_X;
	if ( strcmp(symmetry, "p2mg (m // y)") == 0 ) return PLANEGROUP_P2MG_Y;
	if ( strcmp(symmetry, "p2gg") == 0 ) return PLANEGROUP_P2GG;
	if ( strcmp(symmetry, "c2mm") == 0 ) return PLANEGROUP_C2MM;
	if ( strcmp(symmetry, "p4") == 0 ) return PLANEGROUP_P4;
	if ( strcmp(symmetry, "p4mm") == 0 ) return PLANEGROUP_P4MM;
	if ( strcmp(symmetry, "p4gm") == 0 ) return PLANEGROUP_P4GM;
	if ( strcmp(symmetry, "p3") == 0 ) return PLANEGROUP_P3;
	if ( strcmp(symmetry, "p3m1") == 0 ) return PLANEGROUP_P3M1;
	if ( strcmp(symmetry, "p31m") == 0 ) return PLANEGROUP_P31M;
	if ( strcmp(symmetry, "p6") == 0 ) return PLANEGROUP_P6;
	if ( strcmp(symmetry, "p6mm") == 0 ) return PLANEGROUP_P6MM;

	fprintf(stderr, "Unrecognised symmetry identifier '%s'\n", symmetry);
	return SYMMETRY_IDENTITY;

}

const char *symmetry_decode(Symmetry sym) {

	if ( sym == PLANEGROUP_P1 ) return "p1";
	if ( sym == PLANEGROUP_P2 ) return "p2";
	if ( sym == PLANEGROUP_PM_X ) return "pm (m // x)";
	if ( sym == PLANEGROUP_PM_Y ) return "pm (m // y)";
	if ( sym == PLANEGROUP_PG_X ) return "pg (g // x)";
	if ( sym == PLANEGROUP_PG_Y ) return "pg (g // y)";
	if ( sym == PLANEGROUP_CM_X ) return "cm (m // x)";
	if ( sym == PLANEGROUP_CM_Y ) return "cm (m // y)";
	if ( sym == PLANEGROUP_P2MM ) return "p2mm";
	if ( sym == PLANEGROUP_P2MG_X ) return "p2mg (m // x)";
	if ( sym == PLANEGROUP_P2MG_Y ) return "p2mg (m // y)";
	if ( sym == PLANEGROUP_P2GG ) return "p2gg";
	if ( sym == PLANEGROUP_C2MM ) return "c2mm";
	if ( sym == PLANEGROUP_P4 ) return "p4";
	if ( sym == PLANEGROUP_P4MM ) return "p4mm";
	if ( sym == PLANEGROUP_P4GM ) return "p4gm";
	if ( sym == PLANEGROUP_P3 ) return "p3";
	if ( sym == PLANEGROUP_P3M1 ) return "p3m1";
	if ( sym == PLANEGROUP_P31M ) return "p31m";
	if ( sym == PLANEGROUP_P6 ) return "p6";
	if ( sym == PLANEGROUP_P6MM ) return "p6mm";
	if ( sym == (PLANEGROUP_P1 | SYMMETRY_FRIEDEL) ) return "p1 & Friedel";
	if ( sym == (PLANEGROUP_P2 | SYMMETRY_FRIEDEL) ) return "p2 & Friedel";
	if ( sym == (PLANEGROUP_PM_X | SYMMETRY_FRIEDEL) ) return "pm (m // x) & Friedel";
	if ( sym == (PLANEGROUP_PM_Y | SYMMETRY_FRIEDEL) ) return "pm (m // y) & Friedel";
	if ( sym == (PLANEGROUP_PG_X | SYMMETRY_FRIEDEL) ) return "pg (g // x) & Friedel";
	if ( sym == (PLANEGROUP_PG_Y | SYMMETRY_FRIEDEL) ) return "pg (g // y) & Friedel";
	if ( sym == (PLANEGROUP_CM_X | SYMMETRY_FRIEDEL) ) return "cm (m // x) & Friedel";
	if ( sym == (PLANEGROUP_CM_Y | SYMMETRY_FRIEDEL) ) return "cm (m // y) & Friedel";
	if ( sym == (PLANEGROUP_P2MM | SYMMETRY_FRIEDEL) ) return "p2mm & Friedel";
	if ( sym == (PLANEGROUP_P2MG_X | SYMMETRY_FRIEDEL) ) return "p2mg (m // x) & Friedel";
	if ( sym == (PLANEGROUP_P2MG_Y | SYMMETRY_FRIEDEL) ) return "p2mg (m // y) & Friedel";
	if ( sym == (PLANEGROUP_P2GG | SYMMETRY_FRIEDEL) ) return "p2gg & Friedel";
	if ( sym == (PLANEGROUP_C2MM | SYMMETRY_FRIEDEL) ) return "c2mm & Friedel";
	if ( sym == (PLANEGROUP_P4 | SYMMETRY_FRIEDEL) ) return "p4 & Friedel";
	if ( sym == (PLANEGROUP_P4MM | SYMMETRY_FRIEDEL) ) return "p4mm & Friedel";
	if ( sym == (PLANEGROUP_P4GM | SYMMETRY_FRIEDEL) ) return "p4gm & Friedel";
	if ( sym == (PLANEGROUP_P3 | SYMMETRY_FRIEDEL) ) return "p3 & Friedel";
	if ( sym == (PLANEGROUP_P3M1 | SYMMETRY_FRIEDEL) ) return "p3m1 & Friedel";
	if ( sym == (PLANEGROUP_P31M | SYMMETRY_FRIEDEL) ) return "p31m & Friedel";
	if ( sym == (PLANEGROUP_P6 | SYMMETRY_FRIEDEL) ) return "p6 & Friedel";
	if ( sym == (PLANEGROUP_P6MM | SYMMETRY_FRIEDEL) ) return "p6mm & Friedel";

	return "(unknown symmetry)";

}

void symmetry_symmetrise_array(fftw_complex *in, signed int width, signed int height, Symmetry sym) {

	ReflectionList *reflections;

	reflections = reflist_new_from_array(in, width, height);
	symmetry_symmetrise(reflections, sym, SYMFLAG_PHASES_KNOWN);
	reflist_fill_array(in, reflections, width, height);
	reflist_free(reflections);

}