APPLY_INVERSE_PCA

Inverts the APPLY_PCA-generated transform back to the original coordinate system.

Inverts the APPLY_PCA-generated transform back to the original coordinate system.

Syntax

APPLY_INVERSE_PCA ( input-columns
        USING PARAMETERS model_name = 'model-name'
            [, exclude_columns = 'excluded-columns']
            [, key_columns = 'key-columns'] )

Arguments

input-columns
Comma-separated list of columns to use from the input relation, 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_name

Name of the model (case-insensitive).

exclude_columns

Comma-separated list of column names from input-columns to exclude from processing.

key_columns
Comma-separated list of column names from input-columns that identify its data rows. These columns are included in the output table.

Examples

The following example shows how to use the APPLY_INVERSE_PCA function. It shows the output for the first record.


=> 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)

See also