APPLY_PCA
Transforms the data using a PCA model.
Transforms the data using a PCA model. This returns new coordinates of each data point.
Syntax
APPLY_PCA ( input-columns
USING PARAMETERS model_name = 'model-name'
[, num_components = num-components]
[, cutoff = cutoff-value]
[, match_by_pos = match-by-position]
[, exclude_columns = 'excluded-columns']
[, key_columns = 'key-columns'] )
Arguments
input-columns- Comma-separated list of columns that contain the data matrix, or asterisk (*) to select all columns. The following requirements apply:
-
All columns must be a numeric data type.
-
Enclose the column name in double quotes if it contains special characters.
-
Parameters
model_nameName of the model (case-insensitive).
num_components- The number of components to keep in the model. This is the number of output columns that will be generated. If you omit this parameter and the
cutoffparameter, all model components are kept. cutoff- Set to 1, specifies the minimum accumulated explained variance. Components are taken until the accumulated explained variance reaches this value.
match_by_posBoolean value that specifies how input columns are matched to model features:
-
true: Match by the position of columns in the input columns list. -
false(default): Match by name.
-
exclude_columnsComma-separated list of column names from
input-columnsto exclude from processing.key_columns- Comma-separated list of column names from
input-columnsthat identify its data rows. These columns are included in the output table.
Examples
=> SELECT PCA ('pcamodel', 'world','country,HDI,em1970,em1971,em1972,em1973,em1974,em1975,em1976,em1977,
em1978,em1979,em1980,em1981,em1982,em1983,em1984 ,em1985,em1986,em1987,em1988,em1989,em1990,em1991,em1992,
em1993,em1994,em1995,em1996,em1997,em1998,em1999,em2000,em2001,em2002,em2003,em2004,em2005,em2006,em2007,
em2008,em2009,em2010,gdp1970,gdp1971,gdp1972,gdp1973,gdp1974,gdp1975,gdp1976,gdp1977,gdp1978,gdp1979,gdp1980,
gdp1981,gdp1982,gdp1983,gdp1984,gdp1985,gdp1986,gdp1987,gdp1988,gdp1989,gdp1990,gdp1991,gdp1992,gdp1993,
gdp1994,gdp1995,gdp1996,gdp1997,gdp1998,gdp1999,gdp2000,gdp2001,gdp2002,gdp2003,gdp2004,gdp2005,gdp2006,
gdp2007,gdp2008,gdp2009,gdp2010' USING PARAMETERS exclude_columns='HDI,country');
PCA
---------------------------------------------------------------
Finished in 1 iterations.
Accepted Rows: 96 Rejected Rows: 0
(1 row)
=> CREATE TABLE worldPCA AS SELECT
APPLY_PCA (HDI,country,em1970,em1971,em1972,em1973,em1974,em1975,em1976,em1977,em1978,em1979,
em1980,em1981,em1982,em1983,em1984 ,em1985,em1986,em1987,em1988,em1989,em1990,em1991,em1992,em1993,em1994,
em1995,em1996,em1997,em1998,em1999,em2000,em2001,em2002,em2003,em2004,em2005,em2006,em2007,em2008,em2009,
em2010,gdp1970,gdp1971,gdp1972,gdp1973,gdp1974,gdp1975,gdp1976,gdp1977,gdp1978,gdp1979,gdp1980,gdp1981,gdp1982,
gdp1983,gdp1984,gdp1985,gdp1986,gdp1987,gdp1988,gdp1989,gdp1990,gdp1991,gdp1992,gdp1993,gdp1994,gdp1995,
gdp1996,gdp1997,gdp1998,gdp1999,gdp2000,gdp2001,gdp2002,gdp2003,gdp2004,gdp2005,gdp2006,gdp2007,gdp2008,
gdp2009,gdp2010 USING PARAMETERS model_name='pcamodel', exclude_columns='HDI, country', key_columns='HDI,
country',cutoff=.3)OVER () FROM world;
CREATE TABLE
=> SELECT * FROM worldPCA;
HDI | country | col1
------+---------------------+-------------------
0.886 | Belgium | 79002.2946705704
0.699 | Belize | -25631.6670012556
0.427 | Benin | -40373.4104598122
0.805 | Chile | -16805.7940082156
0.687 | China | -37279.2893141103
0.744 | Costa Rica | -19505.5631231635
0.4 | Cote d'Ivoire | -38058.2060339272
0.776 | Cuba | -23724.5779612041
0.895 | Denmark | 117325.594028813
0.644 | Egypt | -34609.9941604549
...
(96 rows)
=> SELECT APPLY_INVERSE_PCA (HDI, country, col1
USING PARAMETERS model_name = 'pcamodel', exclude_columns='HDI,country',
key_columns = 'HDI, country') OVER () FROM worldPCA;
HDI | country | em1970 | em1971 | em1972 | em1973 |
em1974 | em1975 | em1976| em1977 | em1978 | em1979
| em1980 | em1981 | em1982 | em1983 | em1984 |em1985
| em1986 | em1987 | em1988 | em1989 | em1990 | em1991
| em1992 | em1993| em1994 | em1995 | em1996 | em1997
| em1998 | em1999 | em2000 | em2001 |em2002 |
em2003 | em2004 | em2005 | em2006 | em2007 | em2008
| em2009 | em2010 | gdp1970 | gdp1971 | gdp1972 | gdp1973
| gdp1974 | gdp1975 | gdp1976 | gdp1977 |gdp1978 | gdp1979
| gdp1980 | gdp1981 | gdp1982 | gdp1983 | gdp1984 | gdp1985
| gdp1986| gdp1987 | gdp1988 | gdp1989 | gdp1990 | gdp1991
| gdp1992 | gdp1993 | gdp1994 | gdp1995 | gdp1996 |
gdp1997 | gdp1998 | gdp1999 | gdp2000 | gdp2001 | gdp2002
| gdp2003 |gdp2004 | gdp2005 | gdp2006 | gdp2007 | gdp2008
| gdp2009 | gdp2010
-------+---------------------+-------------------+-------------------+------------------+------------------
+------------------+-------------------+------------------+------------------+-------------------+---------
----------+-------------------+------------------+-------------------+-------------------+-----------------
--+------------------+-------------------+-------------------+-------------------+------------------+-------
-----------+------------------+-------------------+-------------------+------------------+------------------
-+-------------------+------------------+-------------------+-------------------+-------------------+-------
------------+--------------------+------------------+-------------------+------------------+----------------
---+-------------------+-------------------+------------------+-------------------+------------------+------
------------+------------------+------------------+------------------+------------------+------------------+
------------------+------------------+------------------+------------------+------------------+-------------
-----+------------------+------------------+------------------+------------------+------------------+-------
-----------+------------------+------------------+------------------+------------------+------------------+-
-----------------+------------------+------------------+------------------+------------------+--------------
----+------------------+------------------+------------------+------------------+------------------+--------
----------+------------------+------------------+------------------+------------------+------------------
0.886 | Belgium | 18585.6613572407 | -16145.6374560074 | 26938.956253415 | 8094.30475779595 |
12073.5461203817 | -11069.0567600181 | 19133.8584911727| 5500.312894949 | -4227.94863799987 | 6265.77925410752
| -10884.749295608 | 30929.4669575201 | -7831.49439429977 | 3235.81760508742 | -22765.9285442662 | 27200
.6767714485 | -10554.9550160917 | 1169.4144482273 | -16783.7961289161 | 27932.2660829329 | 17227.9083196848
| 13956.0524012749 | -40175.6286481088 | -10889.4785920499 | 22703.6576872859 | -14635.5832197402 |
2857.12270512168 | 20473.5044214494 | -52199.4895696423 | -11038.7346460738 | 18466.7298633088 | -17410.4225137703 |
-3475.63826305462 | 29305.6753822341 | 1242.5724942049 | 17491.0096310849 | -12609.9984515902 | -17909.3603476248
| 6276.58431412381 | 21851.9475485178 | -2614.33738160397 | 3777.74134131349 | 4522.08854282736 | 4251.90446379366
| 4512.15101396876 | 4265.49424538129 | 5190.06845330997 | 4543.80444817989 | 5639.81122679089 | 4420.44705213467
| 5658.8820279283 | 5172.69025294376 | 5019.63640408663 | 5938.84979495903 | 4976.57073629812 | 4710.49525137591
| 6523.65700286465 | 5067.82520773578 | 6789.13070219317 | 5525.94643553563 | 6894.68336419297 | 5961.58442474331
| 5661.21093840818 | 7721.56088518218 | 5959.7301109143 | 6453.43604137202 | 6739.39384033096 | 7517.97645468455
| 6907.49136910647 | 7049.03921764209 | 7726.49091035527 | 8552.65909911844 | 7963.94487647115 | 7187.45827585515
| 7994.02955410523 | 9532.89844418041 | 7962.25713582666 | 7846.68238907624 | 10230.9878908643 | 8642.76044946519
| 8886.79860331866 | 8718.3731386891
...
(96 rows)