[GRASS-user] log function for SQLite

[Moritz Lennert]

On 08/03/17 13:17, Nikos Alexandris wrote:
>
> NikosAlexandris wrote:
>
>>>>>> Dear list,
>>>>>>
>>>>>> where is the extension for SQLite that contains the (mathematical) log
>>>>>> function available to download?  As referenced in
>>>>>> https://grass.osgeo.org/grass73/manuals/v.db.update.html.
>
> Helmut Kudrnovsky:
>
>>>>>> I think the reference in the manual requires a source or a link to it.
>>>>>
>>>>> just found something in the wiki:
>>>>>
>>>>> https://grasswiki.osgeo.org/wiki/Build_SQLite_extension_on_windows
>
> Nikos:
>
>>> For Linux:
>>>
>>> gcc extension-functions.c -fPIC -shared -o libextensionfunctions.so
>>>
>>> Note,
>>>
>>> 1) there is still a "compile" warning for the code (no time to hunt)
>>> 2) The log() function does not like, naturally, 0 values. But this can
>>> be workedaround with a where SQL clause.
>>>
>>> Can we not integrate this into GRASS?  It feels awkward to have to spend
>>> so much time for a log or similar function to use in a v.db.update call.
>
> Moritz:
>
>> -1
>>
>> I don't think we should start interalizing solutions to issues related
>> to database backend choice.
>
> We can of course integrate a log and an "sqrt" function for v.db.update,
> right?

You mean within the v.db.update code ? But why log and sqrt and not others ?

As said, I don't think we should go down that road.

Moritz