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#... 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: [email protected] [[email protected]] on behalf of Luc Bourhis [[email protected]] 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, [email protected]mailto:[email protected] 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? -- This e-mail and any attachments may contain confidential, copyright and or privileged material, and are for the use of the intended addressee only. If you are not the intended addressee or an authorised recipient of the addressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclose the information in or attached to the e-mail. Any opinions expressed within this e-mail are those of the individual and not necessarily of Diamond Light Source Ltd. Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachments are free from viruses and we cannot accept liability for any damage which you may sustain as a result of software viruses which may be transmitted in or with the message. Diamond Light Source Limited (company no. 4375679). Registered in England and Wales with its registered office at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom