From 92010434d45482742ac4d6a04e680cd3dec70104 Mon Sep 17 00:00:00 2001
From: Jan Wieck <JanWieck@Yahoo.com>
Date: Tue, 4 Jul 2000 14:36:03 +0000
Subject: [PATCH] New contrib module for statistical mathematics
Jan
---
contrib/statmath/Makefile | 58 ++++++
contrib/statmath/README.statmath | 39 ++++
contrib/statmath/statmath.c | 307 +++++++++++++++++++++++++++++++
contrib/statmath/statmath.sql.in | 88 +++++++++
4 files changed, 492 insertions(+)
create mode 100644 contrib/statmath/Makefile
create mode 100644 contrib/statmath/README.statmath
create mode 100644 contrib/statmath/statmath.c
create mode 100644 contrib/statmath/statmath.sql.in
diff --git a/contrib/statmath/Makefile b/contrib/statmath/Makefile
new file mode 100644
index 00000000000..cafd36e2b43
--- /dev/null
+++ b/contrib/statmath/Makefile
@@ -0,0 +1,58 @@
+#
+# $Header: /cvsroot/pgsql/contrib/statmath/Attic/Makefile,v 1.1 2000/07/04 14:36:03 wieck Exp $
+#
+
+TOPDIR=../..
+
+include ../Makefile.global
+
+NAME = statmath
+
+PROGRAM =
+OBJS = $(NAME).o
+DOCS = README.$(NAME)
+SQLS = $(NAME).sql
+BINS =
+EXAMPLES=
+MODS = $(NAME)$(DLSUFFIX)
+
+CFLAGS += -I. $(CFLAGS_SL)
+
+OTHER_CLEAN = $(SQLS)
+
+all: $(MODS) $(SQLS)
+
+%.sql: %.sql.in
+ $(SED) "s|MODULE_PATHNAME|$(CONTRIB_MODDIR)/$(NAME)$(DLSUFFIX)|" < $< > $@
+
+install: install_doc install_sql install_mod install_bin
+
+install_doc:
+ for inst_file in $(DOCS); do \
+ $(INSTALL) $(INSTL_LIB_OPTS) $$inst_file $(CONTRIB_DOCDIR); \
+ done
+
+install_sql:
+ for inst_file in $(SQLS); do \
+ $(INSTALL) $(INSTL_LIB_OPTS) $$inst_file $(CONTRIB_SQLDIR); \
+ done
+
+install_mod:
+ for inst_file in $(MODS); do \
+ $(INSTALL) $(INSTL_SHLIB_OPTS) $$inst_file $(CONTRIB_MODDIR); \
+ done
+
+install_bin:
+ for inst_file in $(BINS); do \
+ $(INSTALL) $(INSTL_EXE_OPTS) $$inst_file $(CONTRIB_BINDIR); \
+ done
+
+depend dep:
+ $(CC) -MM -MG $(CFLAGS) *.c > depend
+
+clean:
+ $(RM) *~ $(OBJS) $(MODS) $(PROGRAM) depend $(OTHER_CLEAN) core log
+
+ifeq (depend,$(wildcard depend))
+include depend
+endif
diff --git a/contrib/statmath/README.statmath b/contrib/statmath/README.statmath
new file mode 100644
index 00000000000..7db5f7c673b
--- /dev/null
+++ b/contrib/statmath/README.statmath
@@ -0,0 +1,39 @@
+Statistical aggregate functions for PostgreSQL.
+
+This module provides some aggregate functions for statistical
+mathematics. A new datatype holding two double precision
+floating point values is required by them.
+
+The aggregates are:
+
+average(float8) average value computed by
+
+ n
+ ___
+ _ 1 \
+ x = --- > x
+ n /__ i
+ i=1
+
+
+variance(float8 variance computed by
+
+ n
+ ___
+ 2 1 \ _ 2
+ s = --- > (x - x)
+ n-1 /__ i
+ i=1
+
+
+
+stddev(float8) standard deviation computed by
+
+ _____
+ / 2
+ s = / s
+ \/
+
+
+--
+Jan Wieck <JanWieck@Yahoo.com>
diff --git a/contrib/statmath/statmath.c b/contrib/statmath/statmath.c
new file mode 100644
index 00000000000..f248a2890a6
--- /dev/null
+++ b/contrib/statmath/statmath.c
@@ -0,0 +1,307 @@
+/* ----------
+ * Module statmath
+ *
+ * statistical aggregates for average, variance and standard
+ * deviation.
+ *
+ * Jan Wieck
+ * ----------
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <errno.h>
+
+#include "postgres.h"
+#include "utils/palloc.h"
+
+
+/* ----------
+ * Declarations
+ *
+ * statmath_stateval_in() Input function for state transition variable
+ * statmath_stateval_out() Output function for state transition variable
+ * statmath_collect() State transition function to collect items
+ * statmath_average_fin() Final function for average aggregate
+ * statmath_variance_fin() Final function for variance aggregate
+ * statmath_stddev_fin() Final function for deviation aggregate
+ * ----------
+ */
+
+float64 statmath_stateval_in(char *str);
+char *statmath_stateval_out(float64 sval);
+
+float64 statmath_collect(float64 sval, float64 item);
+float64 statmath_average_fin(float64 sval, int4 n);
+float64 statmath_variance_fin(float64 sval, int4 n);
+float64 statmath_stddev_fin(float64 sval, int4 n);
+
+
+/* ----------
+ * statmath_checkval -
+ *
+ * Bounds checking for float8 values in Postgres
+ * ----------
+ */
+static void
+statmath_checkval(double val)
+{
+ if (fabs(val) > DBL_MAX)
+ elog(ERROR, "statmath: overflow");
+ if (val != 0.0 && fabs(val) < DBL_MIN)
+ elog(ERROR, "statmath: underflow");
+}
+
+
+/* ----------
+ * statmath_stateval_in -
+ *
+ * Input function for the state transition value data type.
+ * The input string are two float8's separated with a colon ':'.
+ * ----------
+ */
+float64
+statmath_stateval_in(char *str)
+{
+ float64 retval;
+ double tmp;
+ char *cp1, *cp2;
+
+ if (!str)
+ return (float64) NULL;
+
+ /*
+ * Allocate space for the result
+ */
+ retval = (float64) palloc(sizeof(float64data) * 2);
+
+ /*
+ * Get the first number
+ */
+ errno = 0;
+ tmp = strtod(str, &cp1);
+ if (*cp1 != ':' || errno == ERANGE)
+ elog(ERROR, "statmath: illegal input format '%s'", str);
+ statmath_checkval(tmp);
+ retval[0] = tmp;
+
+ /*
+ * Get the second number
+ */
+ tmp = strtod(++cp1, &cp2);
+ if (*cp2 != '\0' || errno == ERANGE)
+ elog(ERROR, "statmath: illegal input format '%s'", str);
+ statmath_checkval(tmp);
+ retval[1] = tmp;
+
+ /*
+ * Return the internal binary format
+ */
+ return retval;
+}
+
+
+/* ----------
+ * statmath_stateval_out -
+ *
+ * Output function for the state transition value data type.
+ * ----------
+ */
+char *
+statmath_stateval_out(float64 sval)
+{
+ char buf[1024];
+ double v1, v2;
+
+ if (!sval)
+ return pstrdup("(null)");
+
+ /*
+ * Print the values in the external format and return
+ * the result in allocated space
+ */
+ v1 = sval[0];
+ v2 = sval[1];
+ sprintf(buf, "%.*g:%.*g", DBL_DIG, v1, DBL_DIG, v2);
+ return pstrdup(buf);
+}
+
+
+/* ----------
+ * statmath_collect -
+ *
+ * State transition function to collect data for the variance
+ * and standard deviation aggregates.
+ * The state transition variable holds 2 float8 values. The
+ * first is the sum of the items, the second the sum of the
+ * item quadratic products.
+ * ----------
+ */
+float64
+statmath_collect(float64 sval, float64 item)
+{
+ float64 retval;
+ double tmp;
+
+ if (!sval || !item)
+ return (float64) NULL;
+
+ /*
+ * Allocate space for the result
+ */
+ retval = (float64) palloc(sizeof(float64data) * 2);
+
+ /*
+ * Compute the new values
+ */
+ tmp = sval[0] + *item;
+ statmath_checkval(tmp);
+ retval[0] = tmp;
+
+ tmp = sval[1] + *item * *item;
+ statmath_checkval(tmp);
+ retval[1] = tmp;
+
+ /*
+ * Return the result
+ */
+ return retval;
+}
+
+
+/* ----------
+ * statmath_average_fin -
+ *
+ * Final computation function for the average aggregate.
+ * ----------
+ */
+float64
+statmath_average_fin(float64 sum, int4 n)
+{
+ float64 retval;
+ double tmp;
+
+ if (!sum)
+ return (float64) NULL;
+
+ /*
+ * Allocate space for the result
+ */
+ retval = (float64) palloc(sizeof(float64data));
+
+ /*
+ * Avoid division by zero if no items collected
+ */
+ if (n == 0)
+ {
+ *retval = 0.0;
+ return retval;
+ }
+
+ /*
+ * Compute the average
+ */
+ tmp = *sum / (double)n;
+ statmath_checkval(tmp);
+ *retval = tmp;
+
+ /*
+ * Return the result
+ */
+ return retval;
+}
+
+
+/* ----------
+ * statmath_variance_fin -
+ *
+ * Final computation function for the variance aggregate
+ * ----------
+ */
+float64
+statmath_variance_fin(float64 sval, int4 n)
+{
+ float64 retval;
+ double avg;
+ double variance;
+
+ if (!sval)
+ return (float64) NULL;
+
+ /*
+ * Allocate space for the result
+ */
+ retval = (float64) palloc(sizeof(float64data));
+
+ /*
+ * Avoid division by zero if less than 2 items collected
+ */
+ if (n < 2)
+ {
+ *retval = 0.0;
+ return retval;
+ }
+
+ /*
+ * Calculate the variance
+ */
+ avg = sval[0] / (double)n;
+ variance = (sval[1] - sval[0] * avg) / ((double)n - 1.0);
+
+ statmath_checkval(variance);
+ *retval = variance;
+
+ /*
+ * Return the result
+ */
+ return retval;
+}
+
+
+/* ----------
+ * statmath_stateval_in -
+ *
+ * Input function for the state transition value data type
+ * ----------
+ */
+float64
+statmath_stddev_fin(float64 sval, int4 n)
+{
+ float64 retval;
+ double avg;
+ double stddev;
+
+ if (!sval)
+ return (float64) NULL;
+
+ /*
+ * Allocate space for the result
+ */
+ retval = (float64) palloc(sizeof(float64data));
+
+ /*
+ * Avoid division by zero if less than 2 items collected
+ */
+ if (n < 2)
+ {
+ *retval = 0.0;
+ return retval;
+ }
+
+ /*
+ * Calculate the standard deviation
+ */
+ avg = sval[0] / (double)n;
+ stddev = sqrt((sval[1] - sval[0] * avg) / ((double)n - 1.0));
+
+ statmath_checkval(stddev);
+ *retval = stddev;
+
+ /*
+ * Return the result
+ */
+ return retval;
+}
+
+
diff --git a/contrib/statmath/statmath.sql.in b/contrib/statmath/statmath.sql.in
new file mode 100644
index 00000000000..ce01b460ad5
--- /dev/null
+++ b/contrib/statmath/statmath.sql.in
@@ -0,0 +1,88 @@
+-- statmath.sql
+--
+-- Install the statistical aggregates
+--
+
+--
+-- Create the new data type for the state transition variable
+--
+CREATE FUNCTION statmath_stateval_in(opaque)
+ RETURNS statmath_stateval
+ AS 'MODULE_PATHNAME'
+ LANGUAGE 'C';
+
+CREATE FUNCTION statmath_stateval_out(opaque)
+ RETURNS opaque
+ AS 'MODULE_PATHNAME'
+ LANGUAGE 'C';
+
+CREATE TYPE statmath_stateval (
+ internallength = 16,
+ input = statmath_stateval_in,
+ output = statmath_stateval_out,
+ alignment = double
+);
+
+--
+-- Create the statistic data collector used in the aggregates
+--
+CREATE FUNCTION statmath_collect(statmath_stateval, float8)
+ RETURNS statmath_stateval
+ AS 'MODULE_PATHNAME'
+ LANGUAGE 'C';
+
+--
+-- Create the final functions for the three aggregates
+--
+CREATE FUNCTION statmath_average_fin(float8, int4)
+ RETURNS float8
+ AS 'MODULE_PATHNAME'
+ LANGUAGE 'C';
+
+CREATE FUNCTION statmath_variance_fin(statmath_stateval, int4)
+ RETURNS float8
+ AS 'MODULE_PATHNAME'
+ LANGUAGE 'C';
+
+CREATE FUNCTION statmath_stddev_fin(statmath_stateval, int4)
+ RETURNS float8
+ AS 'MODULE_PATHNAME'
+ LANGUAGE 'C';
+
+--
+-- Create the aggregates themself
+--
+CREATE AGGREGATE average (
+ basetype = float8,
+ stype1 = float8,
+ stype2 = int4,
+ sfunc1 = float8pl,
+ sfunc2 = int4inc,
+ finalfunc = statmath_average_fin,
+ initcond1 = '0',
+ initcond2 = '0'
+);
+
+CREATE AGGREGATE variance (
+ basetype = float8,
+ stype1 = statmath_stateval,
+ stype2 = int4,
+ sfunc1 = statmath_collect,
+ sfunc2 = int4inc,
+ finalfunc = statmath_variance_fin,
+ initcond1 = '0:0',
+ initcond2 = '0'
+);
+
+CREATE AGGREGATE stddev (
+ basetype = float8,
+ stype1 = statmath_stateval,
+ stype2 = int4,
+ sfunc1 = statmath_collect,
+ sfunc2 = int4inc,
+ finalfunc = statmath_stddev_fin,
+ initcond1 = '0:0',
+ initcond2 = '0'
+);
+
+
--
GitLab