... systems.¹

Although in practice, changing the algorithm engine usually involves a change in the primitive and possibly a change in the messaging layer!

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... recipe.²

ORAC-DR does not enforce this rule though and it is possible to include Perl constructs in private recipes and for testing. It should not be done for production code.

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... level³

purely because the recipe level does not contain code

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... primitives⁴

unless the primitive is nested inside another primitive

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...undef⁵

Although it is not possible for a user to specify a primitive argument value of undef this is still good programming practice.

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... extension⁶

the extension used for Starlink N-Dimensional data format (NDF)

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... used)⁷

This is not always a good idea when debugging. Future versions of the pipeline will disable the removal of temporary files when the -debug flag is in use

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... recipe.⁸

It will not simply return undef. The recipe will fail to run since the hash would not have been declared previously.

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... file⁹

For efficiency, the index file is kept in memory rather than read from disk every time it is to be accessed. This means that ORAC-DR is not guaranteed to work if two processes are sharing a single ouput data directory as this would cause problems with index file updates [they are not locked].

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... fixed.¹⁰

currently the one known issue is multiple declarations of the ORAC_PRIMITIVE variable.

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... instrument¹¹

Plans are ongoing to allow multiple search paths for recipes and primitives so that single copies can be used by multiple instruments without having to copy the files to separate locations

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