Add new gvar type for postgres

local_db/postgres_gvar/Makefile

@@ -0,0 +1,35 @@
+#-------------------------------------------------------------------------
+# Author: William Jay (wjay@fnal.gov)
+# Adapted from 
+# https://github.com/postgres/postgres/blob/master/src/tutorial/Makefile
+# Makefile--
+#    Makefile for tutorial
+#
+# By default, this builds against an existing PostgreSQL installation
+# (the one identified by whichever pg_config is first in your path).
+# Within a configured source tree, you can say "make NO_PGXS=1 all"
+# to build using the surrounding source tree.
+#
+# IDENTIFICATION
+#    src/tutorial/Makefile
+#
+#-------------------------------------------------------------------------
+
+MODULES = gvar 
+DATA_built = gvar.sql
+
+ifdef NO_PGXS
+subdir = src/tutorial
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/src/makefiles/pgxs.mk
+else
+PG_CONFIG = /Applications/Postgres.app/Contents/Versions/latest/bin/pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+endif
+
+%.sql: %.source
+	rm -f $@; \
+	C=`pwd`; \
+	sed -e "s:_OBJWD_:$$C:g" < $< > $@

local_db/postgres_gvar/gvar.c

@@ -0,0 +1,263 @@
+/* Author: William Jay (wjay@fnal.gov)
+ * Adapted from 
+ * https://github.com/postgres/postgres/blob/master/src/tutorial/complex.c
+ * 
+ *
+ ******************************************************************************
+  This file contains routines that can be bound to a Postgres backend and
+  called by the backend in the process of processing queries.  The calling
+  format for these routines is dictated by Postgres architecture.
+******************************************************************************/
+
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "libpq/pqformat.h"  /* needed for send/recv functions */
+#include "math.h"            /* needed for sqrt */
+
+PG_MODULE_MAGIC;
+
+typedef struct Gvar
+{
+	double mean;
+	double sdev;
+}			Gvar;
+
+
+/*****************************************************************************
+ * Input/Output functions
+ *****************************************************************************/
+
+PG_FUNCTION_INFO_V1(gvar_in);
+
+Datum
+gvar_in(PG_FUNCTION_ARGS)
+{
+	char *str = PG_GETARG_CSTRING(0);
+	double mean, sdev;
+	Gvar *result;
+
+	if (sscanf(str, " ( %lf , %lf )", &mean, &sdev) != 2)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+				 errmsg("invalid input syntax for type %s: \"%s\"",
+						"gvar", str)));
+
+	result = (Gvar *) palloc(sizeof(Gvar));
+	result->mean = mean;
+	result->sdev = sdev;
+	PG_RETURN_POINTER(result);
+}
+
+PG_FUNCTION_INFO_V1(gvar_out);
+
+Datum
+gvar_out(PG_FUNCTION_ARGS)
+{
+	Gvar *gvar = (Gvar *) PG_GETARG_POINTER(0);
+	char *result;
+
+	result = psprintf("(%g,%g)", gvar->mean, gvar->sdev);
+	PG_RETURN_CSTRING(result);
+}
+
+/*****************************************************************************
+ * Binary Input/Output functions
+ *
+ * These are optional.
+ *****************************************************************************/
+
+PG_FUNCTION_INFO_V1(gvar_recv);
+
+Datum
+gvar_recv(PG_FUNCTION_ARGS)
+{
+	StringInfo buf = (StringInfo) PG_GETARG_POINTER(0);
+	Gvar *result;
+
+	result = (Gvar *) palloc(sizeof(Gvar));
+	result->mean = pq_getmsgfloat8(buf);
+	result->sdev = pq_getmsgfloat8(buf);
+	PG_RETURN_POINTER(result);
+}
+
+PG_FUNCTION_INFO_V1(gvar_send);
+
+Datum
+gvar_send(PG_FUNCTION_ARGS)
+{
+	Gvar    *gvar = (Gvar *) PG_GETARG_POINTER(0);
+	StringInfoData buf;
+
+	pq_begintypsend(&buf);
+	pq_sendfloat8(&buf, gvar->mean);
+	pq_sendfloat8(&buf, gvar->sdev);
+	PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
+}
+
+/*****************************************************************************
+ * New Operators
+ *
+ * A practical Gvar datatype would provide much more than this, of course.
+ *****************************************************************************/
+
+PG_FUNCTION_INFO_V1(gvar_add);
+
+Datum
+gvar_add(PG_FUNCTION_ARGS)
+{
+	Gvar    *a = (Gvar *) PG_GETARG_POINTER(0);
+	Gvar    *b = (Gvar *) PG_GETARG_POINTER(1);
+	Gvar    *result;
+
+	result = (Gvar *) palloc(sizeof(Gvar));
+	result->mean = a->mean + b->mean;
+	result->sdev = sqrt((a)->sdev*(a)->sdev + (b)->sdev*(b)->sdev);
+	PG_RETURN_POINTER(result);
+}
+
+PG_FUNCTION_INFO_V1(gvar_subtract);
+
+Datum
+gvar_subtract(PG_FUNCTION_ARGS)
+{
+    Gvar    *a = (Gvar *) PG_GETARG_POINTER(0);
+    Gvar    *b = (Gvar *) PG_GETARG_POINTER(1);
+    Gvar    *result;
+
+    result = (Gvar *) palloc(sizeof(Gvar));
+    result->mean = a->mean - b->mean;
+	result->sdev = sqrt((a)->sdev*(a)->sdev + (b)->sdev*(b)->sdev);
+	PG_RETURN_POINTER(result);
+}
+
+PG_FUNCTION_INFO_V1(gvar_multiply);
+
+Datum
+gvar_multiply(PG_FUNCTION_ARGS)
+{
+    Gvar    *a = (Gvar *) PG_GETARG_POINTER(0);
+    Gvar    *b = (Gvar *) PG_GETARG_POINTER(1);
+    Gvar    *result;
+
+    result = (Gvar *) palloc(sizeof(Gvar));
+    result->mean = (a)->mean*(b)->mean;
+	result->sdev = sqrt(
+        (b)->mean*(b)->mean * (a)->sdev*(a)->sdev
+        + (a)->mean*(a)->mean * (b)->sdev*(b)->sdev
+    );
+	PG_RETURN_POINTER(result);
+}
+
+PG_FUNCTION_INFO_V1(gvar_divide);
+
+Datum
+gvar_divide(PG_FUNCTION_ARGS)
+{
+    Gvar    *a = (Gvar *) PG_GETARG_POINTER(0);
+    Gvar    *b = (Gvar *) PG_GETARG_POINTER(1);
+    Gvar    *result;
+
+    result = (Gvar *) palloc(sizeof(Gvar));
+    result->mean = (a)->mean/(b)->mean;
+	result->sdev = sqrt(
+        (a)->sdev*(a)->sdev / ((b)->mean*(b)->mean)
+        + (a)->mean*(a)->mean * (b)->sdev*(b)->sdev 
+          / ((b)->mean*(b)->mean*(b)->mean*(b)->mean)
+    );
+	PG_RETURN_POINTER(result);
+}
+
+/*****************************************************************************
+ * Operator class for defining B-tree index
+ *
+ * It's essential that the comparison operators and support function for a
+ * B-tree index opclass always agree on the relative ordering of any two
+ * data values.  Experience has shown that it's depressingly easy to write
+ * unintentionally inconsistent functions.  One way to reduce the odds of
+ * making a mistake is to make all the functions simple wrappers around
+ * an internal three-way-comparison function, as we do here.
+ * 
+ * Ordering operators for gvars will simply use the mean, ignoring the error.
+ *****************************************************************************/
+
+
+static int
+gvar_mean_cmp_internal(Gvar * a, Gvar * b)
+{
+	double		amean = a->mean,
+				bmean = b->mean;
+
+	if (amean < bmean)
+		return -1;
+	if (amean > bmean)
+		return 1;
+	return 0;
+}
+
+
+PG_FUNCTION_INFO_V1(gvar_mean_lt);
+
+Datum
+gvar_mean_lt(PG_FUNCTION_ARGS)
+{
+	Gvar    *a = (Gvar *) PG_GETARG_POINTER(0);
+	Gvar    *b = (Gvar *) PG_GETARG_POINTER(1);
+
+	PG_RETURN_BOOL(gvar_mean_cmp_internal(a, b) < 0);
+}
+
+PG_FUNCTION_INFO_V1(gvar_mean_le);
+
+Datum
+gvar_mean_le(PG_FUNCTION_ARGS)
+{
+	Gvar    *a = (Gvar *) PG_GETARG_POINTER(0);
+	Gvar    *b = (Gvar *) PG_GETARG_POINTER(1);
+
+	PG_RETURN_BOOL(gvar_mean_cmp_internal(a, b) <= 0);
+}
+
+PG_FUNCTION_INFO_V1(gvar_mean_eq);
+
+Datum
+gvar_mean_eq(PG_FUNCTION_ARGS)
+{
+	Gvar    *a = (Gvar *) PG_GETARG_POINTER(0);
+	Gvar    *b = (Gvar *) PG_GETARG_POINTER(1);
+
+	PG_RETURN_BOOL(gvar_mean_cmp_internal(a, b) == 0);
+}
+
+PG_FUNCTION_INFO_V1(gvar_mean_ge);
+
+Datum
+gvar_mean_ge(PG_FUNCTION_ARGS)
+{
+	Gvar    *a = (Gvar *) PG_GETARG_POINTER(0);
+	Gvar    *b = (Gvar *) PG_GETARG_POINTER(1);
+
+	PG_RETURN_BOOL(gvar_mean_cmp_internal(a, b) >= 0);
+}
+
+PG_FUNCTION_INFO_V1(gvar_mean_gt);
+
+Datum
+gvar_mean_gt(PG_FUNCTION_ARGS)
+{
+	Gvar    *a = (Gvar *) PG_GETARG_POINTER(0);
+	Gvar    *b = (Gvar *) PG_GETARG_POINTER(1);
+
+	PG_RETURN_BOOL(gvar_mean_cmp_internal(a, b) > 0);
+}
+
+PG_FUNCTION_INFO_V1(gvar_mean_cmp);
+
+Datum
+gvar_mean_cmp(PG_FUNCTION_ARGS)
+{
+	Gvar    *a = (Gvar *) PG_GETARG_POINTER(0);
+	Gvar    *b = (Gvar *) PG_GETARG_POINTER(1);
+
+	PG_RETURN_INT32(gvar_mean_cmp_internal(a, b));
+}