Re: [patch] Proposal for \rotate in psql - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: [patch] Proposal for \rotate in psql
Date
Msg-id CAFj8pRB90rLbfsnvOskpfAX+t0otkqtJUchMkLLV8U_UvzbeUQ@mail.gmail.com
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In response to Re: [patch] Proposal for \rotate in psql  ("Daniel Verite" <daniel@manitou-mail.org>)
Responses Re: [patch] Proposal for \rotate in psql  ("Daniel Verite" <daniel@manitou-mail.org>)
List pgsql-hackers


2015-09-08 22:55 GMT+02:00 Daniel Verite <daniel@manitou-mail.org>:
        Pavel Stehule wrote:

> rotate ~ sounds like transpose matrix, what is not true in this case.

The various definitions that I can see, such as
http://dictionary.reference.com/browse/rotate
make no mention of matrices. It applies to anything that
moves around a pivot or axis.

OTOH, the established term for the matrix operation you're
referring to appears to be "transpose", as you mention.
https://en.wikipedia.org/wiki/Transpose

I notice that according to
http://www.thesaurus.com/browse/transpose
"rotate" is not present in the 25+ synonyms they suggest for
"transpose".

In the above wikipedia article about matrix transposition,
"rotate" is also never used anywhere.

"rotate matrix" does not exist for google ngrams, whereas
"transpose matrix" does.
https://books.google.com/ngrams

Overall I don't see the evidence that "rotate" alone  would
suggest transposing a matrix.

Now it appears that there is a concept in linear algebra named
"rotation matrix", defined as:
https://en.wikipedia.org/wiki/Rotation_matrix
that seems quite relevant for 3D software.

But as psql is not a tool for linear algebra or 3D in the first place,
who could realistically be deceived?

in the help inside your last patch, you are using "crosstab". Cannto be crosstab the name for this feature?

Regards

Pavel

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