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The ALADIN phasing
This important operation is completed twice a year to "phase" the ALADIN code with its "mother" code ARPEGE.
The ALADIN code is following the ARPEGE one in its permanent evolution (see history of ALADIN cycles). This is due mainly to the technical evolution of calculating machines (CDC, CRAY 2, CRAY C90, FUJITSU, ...) which imposes a new adaptation of the code to the new machine properties.
The evolution of the number of observations over the world dictates also a code development if one wants to take new observations into account.
In addition to these two external constraints, code must contain the newest coding rules if one wants to have a permanent portable one, ...
Code optimisation, as bugs correction, compas bugs correction, computation time and memory winning, ... is also another constraint.
And of course, the evolution of the code is also imposed by the new developments (a development usually involves another one !).
A Phasers'guide defines the rules of these phasings :
The code can be modified for the above-mentioned purposes by a limited number of known developers or phasers to avoid complexity and misunderstanding consequences. Thus, ALADIN code can be touched only by GMAP team, ALADIN partners, some SCEM teams (COMPAS) and of course persons who come to GMAP for training.
The software validation after modification is an absolute must. The phaser or developers must intensively validate its work. After the entire merge of modifications, all the system configurations must be tested and validated. And before using the new software for operational purpose, a double suite is strongly recommended.
So a phaser must keep in mind that he has to respect all coding rules, to check all interactions with the remaining code at each step. He must also phase his scripts and namelists and keep himself informed about all what is being performed into the whole code at the same time.
During the 4th Assembly of ALADIN Partners (Lisbon, December the 6th, 1999), stricter rules for participation to the maintenance effort inside the ALADIN partnership were proposed by Dominique Giard and accepted :
The participation of each ALADIN team to phasing must be at least 1 person once a year. It can be more for the largest teams (more than 4 full-time equivalent persons for instance). The minimum size of a phasing team is 8 persons for a full cycle, less for intermediate cycles if any.
Only one inexperienced person per phasing team is accepted. This newcomer must of course have some basic knowledge of ALADIN.
An ordered list of all ALADIN scientists will be elaborated. Persons will be invited following this list in "rotation mode", so that everyone will contribute but not very often. Each team will send its own part of the list, mentioning constraints if any, to the Toulouse support team. Otherwise the list of quarterly contributions will be used.
Phasing is centralised in Toulouse since a very close co-operation between ALADIN and ARPEGE scientists is required for this crucial exercise. The stays are usually 6 weeks long, costs may be supported by Météo-France. Deported validation of cycles are accepted as contributions to phasing exercises exceptionally, for technical options that cannot be validated in Toulouse.
It was also admitted to dedicate 10% of the ALADIN effort on the maintenance. Maintenance includes not only phasing, but also code optimisation and cleaning, code documentation and the preparation of databases for the use of all partners.