relax 3.2.1

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relax version 3.2.1
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Keywords B14 and B14 full relaxation dispersion models, NS CPMG 2-site expanded model, structure.delete user function
Release type Major bugfix
Release date 23 May 2014

The PDF version of the relax 3.2.1 user manual The relax 3.2.1 user manual


This is a major bugfix release which includes the equations for the B14 and B14 full relaxation dispersion models [Baldwin 2014] introduced with relax version 3.2.0, now being calculated correctly, the NS CPMG 2-site expanded model correctly handling edge cases where no exchange is expected, and the structure.delete user function correctly operating when multiple models are loaded into the data store.


The new relax versions can be downloaded from If binary distributions are not yet available for your platform and you manage to compile the binary modules, please consider contributing these to the relax project (described in section 3.6 of the relax manual,


Version 3.2.1
(23 May 2014, from /trunk)


  • N/A


  • Punctuation fixes throughout the CHANGES document.
  • Modified system test Relax_disp.test_cpmg_synthetic_ns3d_to_cr72 to catch bug #22017: LinAlgError, for all numerical CPMG models. System test was renamed from test_cpmg_synthetic_cr72 to test_cpmg_synthetic_ns3d_to_cr72, to reflect which model create the data and which model fits the data.
  • Modified cpmg_synthetic script to first create all time structures before doing back-calculation. Bug #22017: LinAlgError, for all numerical CPMG models. The numerical models need all time points which are defined in setup to be present when calculating.
  • Renamed system test to test_cpmg_synthetic_ns3d_to_cr72_noise_cluster. The model that creates the data has been changed to numerical model. Bug #22017: LinAlgError, for all numerical CPMG models.
  • Implemented system test Relax_disp.test_cpmg_synthetic_ns3d_to_b14. Bug #22021: model B14 shows bad fitting to data. This is to catch model B14 showing bad fitting behaviour.
  • Parameter precision increase for system test Relax_disp.test_baldwin_synthetic. The correct implementation of the trigonometric functions allow for higher precision. Bug #22021: model B14 shows bad fitting to data. Duplicate line codes were also removed.
  • Code cleanup in system test Relax_disp.test_baldwin_synthetic_full. Bug #22021: model B14 shows bad fitting to data. The precision could also be increased by 1 digit.
  • Code cleanup in system test Relax_disp.test_baldwin_synthetic. Bug #22021: model B14 shows bad fitting to data. Removing many unnecessary lines of code.
  • Added 7 unit tests demonstrating edge case 'no Rex' failures of the NS CPMG 2-site expanded model. This follows from the ideas in the post These tests cover all parameter value combinations which result in no exchange: Δω = 0.0; pA = 1.0; kex = 0.0; Δω = 0.0 and pA = 1.0; Δω = 0.0 and kex = 0.0; pA = 1.0 and kex = 0.0; Δω = 0.0, pA = 1.0, and kex = 0.0. Such tests should be replicated for all dispersion models.
  • Created the Structure.test_bug_22069_structure_delete_helix_attribute system test. This is to catch bug #22069, the failure of the structure.delete user function with "AttributeError: Internal instance has no attribute 'helices'".
  • Created the Structure.test_bug_22070_structure_superimpose_after_deletion system test. This is to catch bug #22070, the failure of the structure.superimpose user function after deleting atoms with structure.delete.
  • Added some checks to the Structure.test_bug_22070_structure_superimpose_after_deletion system test. These tests reveal the real problem - that the atoms of the second model have not been removed by the structure.delete user function.
  • Added git-svn support for the relax version information module. This allows the subversion revision number and repository URL to be displayed on program startup, so that it is stored in log files. This is very useful for debugging purposes.
  • Improvements for the git-svn support in the relax version module. Python 3 is now correctly handled and the URL is properly extracted from the git repository.
  • Improvement for the unit test printouts when run with the --time command line option. The full unit test name is now printed out, reverting to the old behaviour. However the shortened test names are preserved for the other test suite categories.
  • Created the test_ns_cpmg_2site_expanded_no_rex8() relaxation dispersion unit test. This is a demonstration, showing the NS CPMG 2-site expanded model with no exchange when kex = 1e5. I.e. when the motion is too fast for exchange to be observed. This test should be used for all dispersion models to make sure that they model this edge case correctly as well. This follows from
  • Attempt at fixing bug #22071, the relax unit test and system test not functioning. The fix here is that the git commands to show the current subversion revision number only works when run from the relax base directory, or one of the subdirectories. This should now be fixed, as the pipe running the command will first 'cd' to the relax base directory.
  • Another attempt at fixing bug #22071, the relax unit test and system test not functioning. This time the complicated shell command "cd %s; git svn find-rev $(git rev-parse HEAD)" has been replaced with "cd %s; git svn info".
  • Changed most default dispersion parameter values to avoid edge cases where there is no exchange. The Δω parameters were all 0.0 and kex 1e5, both of which result in no exchange. If this is ever used for an optimisation starting point - which it never should, apart from development, test suite, and debugging purposes - then the optimisation algorithm will have a very hard time recovering. The pA parameter has been changed to 0.90 to set it to a reasonable value while still staying far away from the no exchange condition of pA = 1.0. This follows from
  • Fixes for 3 dispersion system tests for the change in default parameter values. The default values are used in the auto-analysis in the test suite to avoid the grid search. The changed values affected the optimisation of two spins from Flemming Hansen's data located at test_suite/shared_data/dispersion/Hansen/, residue 4 used as an example of no exchange and residue 70 used as an example where data is only available at one field. The system test Relax_disp.test_set_grid_r20_from_min_r2eff_cpmg was also modified as it was directly checking these default values.
  • Fix for the Relax_disp.test_cpmg_synthetic_dx_map_points system test. This uses the default parameter values to start the optimisation, therefore the recent change away from edge case 'no Rex' values allows the parameter values stored in ds.dx_clust_val to be correctly optimised.
  • Speed up for the version module when using a repository copy of the code. The repository revision and URL and now stored as module variables, so that the 'svn info' and 'git svn info' commands are only run twice, once for the revision() function and once for the url() function.
  • Large speed up for the relax start up times for svn and git-svn copies of the relax repository. The 'svn info' and 'git svn info' commands are now only executed once when the version module is first imported. The revision() and url() functions have been merged into the repo_info() function and this is called when the module is imported. This repo_info() function stores the repository revision and URL as the version.repo_revision and version.repo_url module variables. It also catches if these variables are already set, so that multiple imports of the module do not cause the repository information to be looked up each time. Previously the revision() and url() functions where called every time a relax state or result file was created, hence for repository copies the 'svn info' or 'git svn info' commands were being called each time. The functions were also called for each interpreter object instantiated, and for each import of the version module.



For reference, the announcement for this release can also be found at following links:

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  • [Baldwin 2014] ^ Baldwin A. J. (2014). An exact solution for R2,eff in CPMG experiments in the case of two site chemical exchange. J. Magn. Reson., 244, 114-124. (DOI: 10.1016/j.jmr.2014.02.023)

See also