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Adding documentation for epoch propagation.
Also, fixing upgrade script generation.
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Diff for: ‎Makefile

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Original file line numberDiff line numberDiff line change
@@ -19,6 +19,7 @@ DATA_built = $(RELEASE_SQL) \
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pg_sphere--1.1.5beta0gavo--1.1.5beta2gavo.sql \
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pg_sphere--1.1.5beta2gavo--1.1.5beta4gavo.sql \
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pg_sphere--1.1.5beta4gavo--1.2.0.sql \
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pg_sphere--1.1.5beta4gavo--1.2.0.sql\
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pg_sphere--1.2.0--1.2.1.sql
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DOCS = README.pg_sphere COPYRIGHT.pg_sphere
@@ -198,12 +199,9 @@ pg_sphere--1.1.5beta4gavo--1.2.0.sql: pgs_moc_ops.sql.in
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cat $^ > $@
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ifeq ($(has_parallel), n)
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sed -i -e '/PARALLEL/d' $@ # version $(pg_version) does not have support for PARALLEL
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pg_sphere--1.2.0-1.2.1.sql: pgs_epochprop.sql.in
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cat upgrade_scripts/$@.in $^ > $@
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endif
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pg_sphere--1.2.0--1.2.1.sql: pgs_moc_geo_casts.sql.in
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pg_sphere--1.2.0--1.2.1.sql: pgs_moc_geo_casts.sql.in pgs_epochprop.sql.in
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cat $^ > $@
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ifeq ($(has_parallel), n)
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sed -i -e '/PARALLEL/d' $@ # version $(pg_version) does not have support for PARALLEL

Diff for: ‎doc/functions.sgm

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@@ -667,5 +667,133 @@
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</example>
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</sect2>
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<sect2 id="funcs.epochprop">
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<title>
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Epoch propagation
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</title>
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<sect3 id="funcs.epochprop.full">
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<title>6-Parameter Epoch Propagation</title>
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<funcsynopsis>
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<funcprototype>
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<funcdef><type>double precision[6]</type>
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<function>epoch_prop</function></funcdef>
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<paramdef>spoint <parameter>pos</parameter></paramdef>
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<paramdef>double precision <parameter>parallax</parameter></paramdef>
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<paramdef>double precision <parameter>pm_long</parameter></paramdef>
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<paramdef>double precision <parameter>pm_lat</parameter></paramdef>
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<paramdef>double precision <parameter>radial_velocity</parameter></paramdef>
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<paramdef>double precision <parameter>delta_t</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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<para>
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Propagates a spherical phase vector in time (in particular,
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applies proper motion to positions)
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</para>
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<para>
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Following both pg_sphere and, where missing, astronomical
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conventions makes units somewhat eclectic here; pm_long and pm_lat
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need to be in rad/yr, whereas parallax is in mas, and
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radial_velocity in km/s. The time difference must be in
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(Julian) years.
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</para>
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<para>
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This function returns a 6-array of [long, lat, parallax,
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pm_long, pm_lat, radial_velocity] of the corresponding values
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delta_t years after the reference epoch for the original position.
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As in the function arguments, long and lat are in rad, pm_lon and
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pm_lat are in rad/yr, parallax is in mas, and radial_velocity is
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in km/s. If you are only interested in the position, consider
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the epoch_prop_pos functions below that have a somewhat less
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contorted signature.
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</para>
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<para>
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It is an error to have either pos or delta_t NULL. For all
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other arguments, NULLs are turned into 0s, except for parallax,
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where some very small default is put in. In that case,
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both parallax and radial_velocity will be NULL in the output
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array.
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</para>
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<para>
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This uses the rigorous method derived in "The Hipparcos and Tycho
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Catalogues", ESA Special Publication 1200 (1997), p 94f. It does
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not take into account relativistic effects, and it also does not
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account for secular aberration.
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</para>
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<example>
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<title>Propagating Barnard's star into the past</title>
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<programlisting><![CDATA[
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SELECT
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to_char(DEGREES(tp[1]), '999D9999999999'),
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to_char(DEGREES(tp[2]), '999D9999999999'),
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to_char(tp[3], '999D999'),
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to_char(DEGREES(tp[4])*3.6e6, '999D999'),
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to_char(DEGREES(tp[5])*3.6e6, '99999D999'),
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to_char(tp[6], '999D999')
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FROM (
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SELECT epoch_prop(
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spoint(radians(269.45207695), radians(4.693364966)), 546.9759,
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RADIANS(-801.551/3.6e6), RADIANS(10362/3.6e6), -110,
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-100) AS tp) AS q;
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to_char | to_char | to_char | to_char | to_char | to_char
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-----------------+-----------------+----------+----------+------------+----------
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269.4742714391 | 4.4072939987 | 543.624 | -791.442 | 10235.412 | -110.450
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]]></programlisting>
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</example>
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</sect3>
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<sect3>
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<title>Epoch Propagation of Positions Only</title>
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<funcsynopsis>
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<funcprototype>
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<funcdef><type>spoint</type>
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<function>epoch_prop_pos</function></funcdef>
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<paramdef>spoint <parameter>pos</parameter></paramdef>
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<paramdef>double precision <parameter>parallax</parameter></paramdef>
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<paramdef>double precision <parameter>pm_long</parameter></paramdef>
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<paramdef>double precision <parameter>pm_lat</parameter></paramdef>
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<paramdef>double precision <parameter>radial_velocity</parameter></paramdef>
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<paramdef>double precision <parameter>delta_t</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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<funcsynopsis>
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<funcprototype>
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<funcdef><type>spoint</type>
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<function>epoch_prop_pos</function></funcdef>
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<paramdef>spoint <parameter>pos</parameter></paramdef>
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<paramdef>double precision <parameter>pm_long</parameter></paramdef>
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<paramdef>double precision <parameter>pm_lat</parameter></paramdef>
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<paramdef>double precision <parameter>delta_t</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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<para>
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These are simplified versions of epoch_prop returning only spoints;
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the propagated values for the other coordinates are discarded
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(but still internallay computed; these functions do not
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run any faster than epoch_prop itself).
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</para>
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<para>
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As with epoch_prop itself, missing values (except for pos and
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delta_t) are substituted by 0 (or a very small value in the
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case of parallax).
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</para>
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<example>
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<title>Barnard's star, position and proper motion</title>
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<programlisting><![CDATA[
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SELECT epoch_prop_pos(
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spoint(radians(269.45207695), radians(4.693364966)),
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RADIANS(-801.551/3.6e6), RADIANS(10362/3.6e6),
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20) AS tp;
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tp
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-----------------------------------------
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(4.70274793061952 , 0.0829193989380876)
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]]></programlisting>
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</example>
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</sect3>
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</sect2>
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</sect1>

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