- cctbxbb - phenix-online.org

reflection conditions for non-standard settings
by David Waterman 06 Jun '11

06 Jun '11

Hi, I'm new to cctbx and to this mailing list, so please let me first apologise if the answer to this question should be obvious, or lies in the archive. I want a list of general reflection conditions for all space groups and settings listed in the CCP4 file syminfo.lib. At first I thought I could get this information from the online version of ITC vol A, but I soon realised that only certain standard settings are included. To avoid deriving them all by hand from the symop and cenop lines, I wonder if there is a foolproof way I can get this information from cctbx, but I don't know where to begin. Perhaps something in sgtbx? Many thanks -- David

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Introducing arbitrary translations in symmetry operations
by Emre S. Tasci 04 Jun '11

04 Jun '11

Dear All, We are trying to identify affine normalizers' space group from the additional operators, but having difficulties in introducing the arbitrary translations. As an example, suppose that our "base" space group is 25, and the additional operators are: -x,-y,-z x+1/2,y,z x,y+1/2,z x,y,z+t which, combined, defines P1 mmm But we couldn't find a way to introduce "x,y,z+t" while we are "expand_smx"ing the space group with these operators. Any ideas how to do this? With my thanks in advance, Emre -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Emre S. Tasci - http://www.emresururi.com Fisica de la Materia Condensada Facultad de Ciencia y Tecnologia Universidad del Pais Vasco Apartado 644 48080 Bilbao / Spain -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

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Re: [cctbxbb] Best way to compare incomplete f_hkl to calculated f_hkl
by Ralf W. Grosse-Kunstleve 11 Apr '11

11 Apr '11

Hi Jan, There are two steps to think about: .map_to_asu() and .common_set() or .common_sets(). Look for these methods in cctbx/regression/tst_miller.py, then add print statements to see how they work (run the command with e.g. "P31" so that it only exercisesone space group). However, the best way to compute f_calc given an array of f_obs is via f_calc = f_obs.structure_factors_from_scatterers( xray_structure).f_calc() This way the f_calc are directly compatible with the f_obs array. Ralf >________________________________ >From: Jan Marten Simons <marten(a)xtal.rwth-aachen.de> >To: cctbxbb(a)phenix-online.org >Sent: Monday, April 11, 2011 3:00 AM >Subject: Re: [cctbxbb] Best way to compare incomplete f_hkl to calculated f_hkl > >Hi, > >I'm looking at the best (=fastest) way to compare a (possibly incomplete) list >of observed reflections f_hkl_obs (or fo2_hkl_obs) to the f_hkl_calc of >calculated structure factors or intensities from a model structure. > >in miller.py there is a function to calculate a difference between f_obs and >f_calc, but it asserts that all reflections are present in f_obs: > >def f_obs_minus_f_calc(self, f_obs_factor, f_calc): >assert f_calc.is_complex_array() >assert self.indices().all_eq(f_calc.indices()) >assert self.anomalous_flag() is f_calc.anomalous_flag() >... > >In my case it's possible that some reflections could not be observed so they >should either be skipped or be assumed to be of zero intensity. As I could not >locate the definition for .all_eq(...), yet I'm not sure if this is already >handled and if it is how it is done. > >Then there is f_obs_minus_xray_structure_f_calc in miller.py as well. Would >this be a better approach if the model structure changes quite often? What if >I just got f_calc from another source (like doing some custom sped-up partial >structure factor calculation)? > >In general: What would be your advice on this with cctbx? > > >With regards, > >Dipl. Phys. > Jan M. Simons > >Institute of Crystallography >RWTH Aachen University >_______________________________________________ >cctbxbb mailing list >cctbxbb(a)phenix-online.org >http://phenix-online.org/mailman/listinfo/cctbxbb > > >

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Best way to compare incomplete f_hkl to calculated f_hkl
by Jan Marten Simons 11 Apr '11

11 Apr '11

Hi, I'm looking at the best (=fastest) way to compare a (possibly incomplete) list of observed reflections f_hkl_obs (or fo2_hkl_obs) to the f_hkl_calc of calculated structure factors or intensities from a model structure. in miller.py there is a function to calculate a difference between f_obs and f_calc, but it asserts that all reflections are present in f_obs: def f_obs_minus_f_calc(self, f_obs_factor, f_calc): assert f_calc.is_complex_array() assert self.indices().all_eq(f_calc.indices()) assert self.anomalous_flag() is f_calc.anomalous_flag() ... In my case it's possible that some reflections could not be observed so they should either be skipped or be assumed to be of zero intensity. As I could not locate the definition for .all_eq(...), yet I'm not sure if this is already handled and if it is how it is done. Then there is f_obs_minus_xray_structure_f_calc in miller.py as well. Would this be a better approach if the model structure changes quite often? What if I just got f_calc from another source (like doing some custom sped-up partial structure factor calculation)? In general: What would be your advice on this with cctbx? With regards, Dipl. Phys. Jan M. Simons Institute of Crystallography RWTH Aachen University

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Use of cctbx with C++
by Flavio Zamponi 16 Mar '11

16 Mar '11

Hi all, I would like to use cctbx with C++. To start with I would like to do something basic, like: >/ from cctbx import xray />/ />/ xs = xray.structure.from_cif(file_path="my.cif") / I looked into the cctbx functions/class list, but I could not find something similar for C++. Can someone help me? Many thanks in advance, Flavio

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Docstrings and online reference
by Jan Marten Simons 11 Feb '11

11 Feb '11

Hi all, as you might have noticed I started to add some docstrings to functions. The purpose of those is to give a user of the toolbox an idea of this: 1. What's the purpose of the object (function/method/class/...)? 2. What objects should be thrown at it as input/keyword arguments? 3. What kind of object does one get as return value? I try to extract the information only from the source code, so it's possible that I sometimes don't get it right, as I'm just starting to explore the inner workings of the toolbox and esp. phenix related parts are (yet) quite obscure for me. I'm trying to document objects in a consistent way, so that a user (as well as ourself) doesn't get confused. I invite you all to adapt the scheme for new functions/objects you code and request comments on further improving it before extending its use, so that it's useful and to your likeing as well. A current example of one such docstring: def set_u_iso(self, value = None, values = None, selection = None): """Set isotropic mean thermic displacements of scatterers Input: value -- (optional) a single double value to set all u_iso of selected scatterers to values -- (optional) an array of double values to set all u_iso of selected scatterers to selection -- (optional) an array of bools to select scatterers to be updated with new u_iso values Returns: cctbx.xray.structure """ [...] During my first pass I noticed some already existing docstrings which are also shown in the online docs at e.g. http://cctbx.sourceforge.net/current/python/cctbx.xray.structure.html. Are those pages automatically generated via a cronjob or does it take a manual update to get this information up2date? Cheers, Jan

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Missing gaussians for some ions?
by Jan Marten Simons 24 Dec '10

24 Dec '10

Hi, I did some more tests using cif files from cod and found out that some of those trigger errors like this for http://www.crystallography.net/cif/1/1000029.cif: Traceback (most recent call last): File "Check_F_calc.py", line 29, in <module> f_calc = structure.structure_factors(d_min=1.0).f_calc() File "/home/marten/Arbeit/cctbx- latest/cctbx_sources/cctbx/xray/structure.py", line 813, in structure_factors algorithm=algorithm) File "/home/marten/Arbeit/cctbx- latest/cctbx_sources/cctbx/xray/structure_factors/from_scatterers.py", line 53, in __call__ miller_set=miller_set) File "/home/marten/Arbeit/cctbx- latest/cctbx_sources/cctbx/xray/structure_factors/from_scatterers_fft.py", line 32, in __init__ tolerance_positive_definite=manager.tolerance_positive_definite()) RuntimeError: gaussian not defined for scattering_type "Y4+". The cif file itself can be read and gives a valid summary: Number of scatterers: 13 At special positions: 5 Unit cell: (7.82927, 7.82927, 5.70757, 90, 90, 120) Space group: P 3 1 c (No. 159) Label, Scattering, Multiplicity, Coordinates, Occupancy, Uiso, Ustar as Uiso Y1 Y4+ 2 ( 0.3333 0.6667 0.2420) 0.27 0.0000 [ - ] Si1 Si4+ 6 ( 0.5087 0.0819 0.2130) 0.77 0.0000 [ - ] Al1 Al3+ 6 ( 0.5087 0.0819 0.2130) 0.23 0.0000 [ - ] Si2 Si4+ 6 ( 0.1706 0.2533 0.0020) 0.77 0.0000 [ - ] Al2 Al3+ 6 ( 0.1706 0.2533 0.0020) 0.23 0.0000 [ - ] N1 N3- 2 ( 0.0000 0.0000 0.0000) 0.94 0.0000 [ - ] O1 O2- 2 ( 0.0000 0.0000 0.0000) 0.06 0.0000 [ - ] N2 N3- 2 ( 0.3333 0.6667 0.6530) 0.94 0.0000 [ - ] O2 O2- 2 ( 0.3333 0.6667 0.6530) 0.06 0.0000 [ - ] N3 N3- 6 ( 0.3458 -0.0472 -0.0050) 0.94 0.0000 [ - ] O3 O2- 6 ( 0.3458 -0.0472 -0.0050) 0.06 0.0000 [ - ] N4 N3- 6 ( 0.3219 0.3180 0.2460) 0.94 0.0000 [ - ] O4 O2- 6 ( 0.3219 0.3180 0.2460) 0.06 0.0000 [ - ] Y1: 0.3333 0.6667 0.2420 point group type: 3 special position operator: 1/3,2/3,z Si1: 0.5087 0.0819 0.2130 point group type: 1 special position operator: x,y,z Al1: 0.5087 0.0819 0.2130 point group type: 1 special position operator: x,y,z Si2: 0.1706 0.2533 0.0020 point group type: 1 special position operator: x,y,z Al2: 0.1706 0.2533 0.0020 point group type: 1 special position operator: x,y,z N1: 0.0000 0.0000 0.0000 point group type: 3 special position operator: 0,0,z O1: 0.0000 0.0000 0.0000 point group type: 3 special position operator: 0,0,z N2: 0.3333 0.6667 0.6530 point group type: 3 special position operator: 1/3,2/3,z O2: 0.3333 0.6667 0.6530 point group type: 3 special position operator: 1/3,2/3,z N3: 0.3458 -0.0472 -0.0050 point group type: 1 special position operator: x,y,z O3: 0.3458 -0.0472 -0.0050 point group type: 1 special position operator: x,y,z N4: 0.3219 0.3180 0.2460 point group type: 1 special position operator: x,y,z O4: 0.3219 0.3180 0.2460 point group type: 1 special position operator: x,y,z Other cif files give other missing gaussians: http://www.crystallography.net/cif/1/1000145.cif: > RuntimeError: gaussian not defined for scattering_type "V4+". http://www.crystallography.net/cif/1/1000181.cif: > RuntimeError: gaussian not defined for scattering_type "H1+". http://www.crystallography.net/cif/1/1000353.cif: > RuntimeError: gaussian not defined for scattering_type "H1+". I'm not sure if this is a problem related to the notation used in those cif files or if cctbx is missing some data here that should be added to it. With regards, Dipl. Pyhs. Jan M. Simons Institute of Crystallography RWTH Aachen University

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State of python3 support?
by Jan Marten Simons 16 Dec '10

16 Dec '10

Hi, as I've noticed from the changelogs cctbx is closely following python 2.x releases. Now I wonder if there are plans to move over to python3 soon? If I got it right, python 2.6 and 2.7 already offer most of python3 features and syntax as optional modules, so that the code can be prepared in advance (like converting print into print()-functions etc. [1] has some ideas on why and how to do a port. So I'm interested in your thoughts about python3 and cctbx. [1] http://peadrop.com/blog/2009/04/05/porting-your-code-to-python-3/ With regards, Jan M. Simons Institute of Crystallography RWTH Aachen

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How to load a structure from a .cif file?
by Jan Marten Simons 15 Dec '10

15 Dec '10

Hi, I've just started to work up some code for my phd. I've found cctbx to be quite a nice code base for my goals. So far I've seen that there is quite a large ammount of functions implemented, but in my opinion documentation on how to use them is either hidden or not in very verbose state. So from looking at the source I'm pretty confident that cctbx can load a crystalstructure from a .cif file (like those obtained from COD, http://www.crystallography.net/). But so far I've not been able to figure out how to do this. My experiments included: from iotbx import crystal_symmetry_from_any as sym_from_any from iotbx import file_reader file_name = "./xtal_data/9008806.cif" structure = file_reader.any_file(file_name) #gives an object, but not a structure # or structure = sym_from_any.extract_from(file_name) # returns none print(str(structure)) structure.show_summary().show_scatterers() Could you give me a hint into the right direction, please? With regards, Jan Simons

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Re: [cctbxbb] Help : CCTBX working
by Swapnil U Shinde 25 Nov '10

25 Nov '10

Hello I have installed CCTBX correctly and both tests run fine.Though when I try to import cctbx it throwing me error as 'no module named cctbx' e.g from cctbx import xray ImportError: No module named cctbx Does it mean python is not properly linked with cctbx.Please help me on this. Additional info: Python 2.6.6 Windows 7 OS Please let me know how to resolve this issue. Thanks in advance.. Thanks & Regards Swapnil U. Shinde ----- Original Message ----- From: Swapnil U Shinde <sshinde2(a)gmu.edu> Date: Tuesday, November 23, 2010 2:51 pm Subject: Help : CCTBX working > Hello > I am using EPD for python,numpy,scipy and cctbx on windows 7 > machine.(I compiled cctbx from windows studio 2010). Test results > for all are attached herewith. > In my code cctbx is accessed as - > ######### > cmmd2 = "cctbx.python \"" > cmddir = FIXDIR(os.getcwd()) > print "os.getcwd" > print os.getcwd() > print "****MML****: GetUnitCell_2.py" > cmmd2 = cmmd2 + cmddir + "GetUnitCell_2.py\"" > print "cmmd2" > print cmmd2 > #-------------------------------------- > # Execute GetUnitCell.py > #-------------------------------------- > bufsize = 1 > try: > print "*** Executing cctbx" > p2 = Popen(cmmd2, shell=True, bufsize=bufsize, stdin=PIPE, > stdout=PIPE, stderr=PIPE) > output2 = p2.communicate(input = allout) > ############# > cmmd2 is showing correct path of module GetUnitCell_2.py. However > output2 is coming empty which shows cctbx is not being accessed > properly. I am not sure whether it is because of faulty > installation or bug in code. > > Please advise how to proceed on this issue.I am stuck on it for > long time. > Thanks in advance!!! > > Thanks & Regards > Swapnil U. Shinde >

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