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[LPT and DA Challenge] [1st LPT and DA challenge] New upload deadline + final instructions

LPT and DA Challenge
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leclaire has sent you a group email from First LPT and DA challenge.

Dear registered user on the 1st LPT and DA challenge data portal,

With the perspective of result upload, we would like to inform you about some changes in the challenge instructions, and provide the practical details for upload.


1. Date changes and registration reminder

The due date for uploading processed results has been slightly postponed, it is now July 17th, 2020.

We remind that in order to be considered as a participant to the challenge(s), in addition to uploading your results you should also be registered to the 3rd CFD for PIV workshop, during which the analysis of the results will be presented. If this is not the case yet, please visit the workshop webpage,, which will give you all the information about the workshop, and the link for registration ( In this registration form, select ‘Yes’ for ‘Intending to participate at DA- or LPT- challenge’.  

Please also note the date of the workshop: it is now November 19-20, 2020, in Paris.


2. Changes in the instructions to participants (file ‘1st LPT and DA Challenge Instructions.pdf’)

Some changes have been performed in the instructions, which are highlighted in green in the PDF document (see this file for the complete updated informations):

  • As requested by several teams, we decided to allow uploading two result files per dataset, if these results stem from two different algorithms.
  • Output file naming (sections 2.4 and 3.3): to ease result processing, we now request that each file begins with the participant name. In case you upload two different results, please distinguish them in your participant name.
  • Section 3.3 pertaining to DA output has been modified. Changes pertain to:
    • Correction of output mesh definition: axes Y and Z were spuriously swapped
    • Correction of pressure normalisation in the results did not consider the right location as a reference
    • Example scripts for generating the results in the proper hdf5 format are now available in the ‘Challenge files’ section, both in Python ( and Matlab (Generate_DA_output.m). Please use the commands in these scripts in order to generate properly formatted output files.

3. Instructions for result upload

In the coming days, each user with a validated account will receive an email informing that a dedicated directory for upload has been set up, within directory ‘Result Upload’ in the ‘Challenge files’ section of the portal. Each user will be able to see only his/her own directory and its contents, and upload in it only. When the case arises, one directory per team gathering several registered users will be created, and the email informing of the creation will be sent jointly to all these users.

Please then upload in your directory each of your result files, by using the naming detailed in the instructions. Also, do not forget to upload a text file containing a half page description of the algorithms used, which is to be included (possibly in a summarized form) during the results presentation. If you submit results obtained with two different algorithms, then the description (which can be longer) should specify how they differ.


In case of questions about all these aspects, please do not hesitate to contact me by e-mail.

Best regards

Benjamin Leclaire, on behalf of the organizers