[gmx-users] umbrella-histogram-windows

[parto haghighi]

Dear gmx users
I am working on an umbrella sampling system.(lipid bilayer+drug).
I have used distance
I have used lipid as a refrence group and drug as a pull group.in
npt_umbrella mdp I have used constraint for refrence group and in
md_umbrella I have removed the constraint.
After that my summery.dat file contains following data:
0	2.2163574
1	2.2125353
2	2.1688467
3	2.1041310
4	2.0907198
5	2.0372755
6	2.0344109
7	2.0205807
8	2.0188276
9	2.0063477
10	2.0100271
11	1.9960003
12	2.0011811
13	1.9741284
14	1.9680872
15	1.9487932
16	1.8766397
17	1.7200924
18	1.6762846
19	1.5760427
20	1.4725303
21	1.4852792
22	1.3151125
23	1.1968731
24	1.1196491
25	1.0879384
26	1.1214086
27	1.0457795
28	1.1297384
29	1.0547690
30	1.1172924
31	1.2132208
32	1.2790826
33	1.2556396
34	1.2034254
35	1.0906192
36	1.0417964
37	1.1047103
38	1.1989108
39	1.2073846
40	1.1673214
41	1.0815340
42	1.1169575
43	1.1769875
44	1.2455147
45	1.1928731
46	1.1054069
47	1.0790326
48	1.1362654
49	1.1214680
50	1.0738213
51	1.0363408
52	1.0989448
53	1.1428183
54	1.1201882
55	1.1889806
56	1.2362384
57	1.2051160
58	1.2037644
59	1.2171633
60	1.2363109
61	1.2392871
62	1.2603214
63	1.2539344
64	1.1282977
65	1.1482411
66	1.1867742
67	1.1649172
68	1.1241708
69	1.1105422
70	1.1251793
71	1.0987285
72	1.1251851
73	1.1679051
74	1.1052191
75	1.1244428
76	1.1386129
77	1.1365076
78	1.1383851
79	1.1449340
80	1.1346834
81	1.1167825
82	1.0945875
83	1.1300997
84	1.1428297
85	1.1867594
86	1.1590696
87	1.1404225
88	1.1742213
89	1.1349461
90	1.1314867
91	1.1361587
92	1.1224793
93	1.1788386
94	1.1498441
95	1.1506270
96	1.1064949
97	1.1546595
98	1.1564190
99	1.0714226
100	1.1199773
101	1.1281228
102	1.1524893
103	1.1595686
104	1.1536553
105	1.1890795
106	1.1438330
107	1.1567581
108	1.1610076
109	1.1843101
110	1.1461171
111	1.1774145
112	1.1266857
113	1.1730814
114	1.1112221
115	1.1658539
116	1.1526571
117	1.1057193
118	1.1287234
119	1.2012605
120	1.1389650
121	1.1590703
122	1.1685155
123	1.1321938
124	1.1486048
125	1.1461945
126	1.1769872
127	1.1249954
128	1.1714567
129	1.1397712
130	1.2048318
131	1.1261573
132	1.1649654
133	1.1346296
134	1.1994447
135	1.1558460
136	1.1871395
137	1.1626594
138	1.1184026
139	1.1341229
140	1.1324711
141	1.1030517
142	1.1764932
143	1.1264903
144	1.1322395
145	1.1227130
146	1.1129291
147	1.1315118
148	1.1746687
149	1.1266127
150	1.1803793
151	1.1231681
152	1.1136831
153	1.1268005
154	1.1447661
155	1.1451746
156	1.1446071
157	1.1281052
158	1.1278596
159	1.1505933
160	1.1632346
161	1.1634330
162	1.1200876
163	1.1263421
164	1.1532616
165	1.1385699
166	1.1633223
167	1.1415736
168	1.1360134
169	1.1299793
170	1.1757061
171	1.1165316
172	1.1547863
173	1.1442331
174	1.1547793
175	1.1619559
176	1.0891477
177	1.2072016
178	1.0957750
179	1.1775378
180	1.1678475
181	1.1312756
182	1.1353923
183	1.1531162
184	1.1581031
185	1.1339137
186	1.1845239
187	1.1742307
188	1.1601242
189	1.1375409
190	1.1153691
191	1.1614760
192	1.1293349
193	1.2212412
194	1.1004681
195	1.1768598
196	1.1651047
197	1.1433749
198	1.1317539
199	1.1521342
200	1.1553539
201	1.1589068
202	1.1888202
203	1.1139559
204	1.0850017
205	1.1767445
206	1.1000916
207	1.1339216
208	1.1156967
209	1.1692301
210	1.1610108
211	1.1196257
212	1.0764190
213	1.1954692
214	1.1750859
215	1.1475511
216	1.2494902
217	1.3200271
218	1.3524807
219	1.2711932
220	1.2862429
221	1.2441974
222	1.1245995
223	1.1403349
224	1.1821948
225	1.1194941
226	1.2166983
227	1.1187817
228	1.1529719
229	1.1997244
230	1.2553700
231	1.2353689
232	1.2522210
233	1.2437250
234	1.2698068
235	1.2502098
236	1.2633507
237	1.2545269
238	1.1212504
239	1.2201137
240	1.1697107
241	1.1291697
242	1.1705309
243	1.1632101
244	1.1949524
245	1.0947707
246	1.1494623
247	1.1255785
248	1.1695995
249	1.1463469
250	1.1618913
251	1.1328190
252	1.1561620
253	1.1524103
254	1.1164197
255	1.2098684
256	1.0705856
257	1.1655772
258	1.1455529
259	1.1588525
260	1.1378038
261	1.2334902
262	1.1669033
263	1.1166701
264	1.2513789
265	1.2197116
266	1.1542124
267	1.1439006
268	1.1764008
269	1.1560290
270	1.1297302
271	1.1459278
272	1.1193644
273	1.1963632
274	1.1195823
275	1.1798624
276	1.1239418
277	1.1408878
278	1.1209821
279	1.1570644
280	1.1687217
281	1.1703171
282	1.1599334
283	1.2152494
284	1.1819685
285	1.1444129
286	1.1373526
287	1.1522148
288	1.1955314
289	1.1804147
290	1.1278866
291	1.1855028
292	1.1350925
293	1.1918853
294	1.3350349
295	1.3654863
296	1.3674002
297	1.2899203
298	1.2829879
299	1.3052024
300	1.3288844
301	1.2837309
302	1.3256962
303	1.3243275
304	1.2473432
305	1.2359587
306	1.2649387
307	1.2660151
308	1.1724662
309	1.0874159
310	1.1483515
311	1.1234104
312	1.0911723
313	1.1726278
314	1.1236658
315	1.1503312
316	1.1483864
317	1.1385110
318	1.1450268
319	1.1258433
320	1.1607553
321	1.1851472
322	1.0866253
323	1.1584546
324	1.1706716
325	1.1875124
326	1.1405223
327	1.1409515
328	1.1348391
329	1.1583944
330	1.1505178
331	1.1372125
332	1.1527471
333	1.1294298
334	1.1278995
335	1.1661187
336	1.1231481
337	1.1155541
338	1.1182202
339	1.2047386
340	1.3277398
341	1.3305781
342	1.3356986
343	1.3074728
344	1.3149188
345	1.3659440
346	1.2956467
347	1.2984017
348	1.3240537
349	1.3195872
350	1.1910413
351	1.1419021
352	1.2791880
353	1.2110095
354	1.2410124
355	1.2374715
356	1.2517792
357	1.2964147
358	1.2125144
359	1.2226928
360	1.2527926
361	1.2526986
362	1.2585649
363	1.2118053
364	1.1915550
365	1.0578706
366	1.1585858
367	1.2330620
368	1.2205206
369	1.2902780
370	1.2496578
371	1.3022352
372	1.2931545
373	1.3098337
374	1.2268461
375	1.2309457
376	1.1559575
377	1.1523703
378	1.2773541
379	1.2432717
380	1.2776868
381	1.2967623
382	1.3015278
383	1.2940338
384	1.2748120
385	1.2233861
386	1.2562447
387	1.2719577
388	1.3442591
389	1.2361699
390	1.2806933
391	1.2778905
392	1.3138871
393	1.3569471
394	1.2524719
395	1.2874336
396	1.2607288
397	1.2356847
398	1.3131601
399	1.2253601
400	1.1105402
401	1.1580552
402	1.1277891
403	1.1714592
404	1.0912436
405	1.1864986
406	1.1878401
407	1.1372809
408	1.1702988
409	1.2193290
410	1.2647056
411	1.2543653
412	1.3284186
413	1.3181866
414	1.3686719
415	1.4521370
416	1.4641754
417	1.4523519
418	1.5920088
419	1.5980577
420	1.5489434
421	1.4902735
422	1.5826549
423	1.5600006
424	1.5902211
425	1.5323428
426	1.5456631
427	1.5273204
428	1.5900084
429	1.5412893
430	1.5962194
431	1.5370157
432	1.4973781
433	1.5288886
434	1.5560608
435	1.5629433
436	1.5456027
437	1.5347616
438	1.5467555
439	1.5660588
440	1.5592589
441	1.5447172
442	1.5793159
443	1.5243505
444	1.5337485
445	1.5812923
446	1.5076854
447	1.5527291
448	1.5599996
449	1.5375631
450	1.5507294
451	1.4763156
452	1.5596538
453	1.4723976
454	1.4742548
455	1.4885223
456	1.5286931
457	1.5812750
458	1.5992634
459	1.6721720
460	1.5979157
461	1.5882409
462	1.6096119
463	1.6853847
464	1.5547028
465	1.4746356
466	1.5158916
467	1.4675600
468	1.5343397
469	1.3681053
470	1.5010762
471	1.4803838
472	1.4953094
473	1.5424787
474	1.5200848
475	1.5052415
476	1.4971479
477	1.6006268
478	1.5689414
479	1.5624480
480	1.5368186
481	1.5469188
482	1.5405121
483	1.5489655
484	1.5677957
485	1.5555471
486	1.5745570
487	1.5241419
488	1.5673757
489	1.5205972
490	1.5468128
491	1.5371502
492	1.5486749
493	1.5264599
494	1.5077617
495	1.6062210
496	1.5399962
497	1.5931936
498	1.6058899
499	1.6357416
500	1.5546903

I have applied  0,3,9,15,16,17,18,19,20,22,39,42 and 51 (from 0 to
500) points for my umbrella sampling.following are my questions:
1.why do not the points descend regularly when the drug is going to
center of membrane?
2.In my histogram curve I only have 1 peak on the 2nd point of my 13
points above,why?
thanks a lot in progress