[cctbxbb] Unstable platform-dependent sort order for flex.sort_permutation

[richard.gildea at diamond.ac.uk]

Hi Luc,

Yes, the random numbers generated by the mersenne twister were the same, however the input tmp_array was in a different sort order, which meant that the output half datasets were platform-dependent:

https://github.com/cctbx/cctbx_project/blob/master/cctbx/miller/__init__.py#L4700

I have just committed the necessary changes to add the parameter stable(=False) to flex.sort_permutation(). miller.array.sort_permutation sets stable=True when calling flex.sort_permutation(). This looks to have made the CC1/2 calculations platform-independent.

Cheers,

Richard

Dr Richard Gildea
Data Analysis Scientist
Tel: +441235 77 8078

Diamond Light Source Ltd.
Diamond House
Harwell Science & Innovation Campus
Didcot
Oxfordshire
OX11 0DE
________________________________
From: cctbxbb-bounces at phenix-online.org [cctbxbb-bounces at phenix-online.org] on behalf of Luc Bourhis [luc_j_bourhis at mac.com]
Sent: 18 November 2016 17:06
To: cctbx mailing list
Subject: Re: [cctbxbb] Unstable platform-dependent sort order for flex.sort_permutation


On 18 Nov 2016, at 17:55, richard.gildea at diamond.ac.uk<mailto:richard.gildea at diamond.ac.uk> wrote:

Luc: split_unmerged splits an unmerged dataset into two random half datasets, in order to calculate the correlation coefficient between the two half datasets:

oh, so you mean that using the same random seed on MacOS and on Linux you did not get the same CC then?


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