| Column # | Content | ||||||
| 1 | The value in column 1, row n of the table array. | ||||||
| 2 |
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| 3 | The value in column column, row n of the table array. |
Investment Studio > Expressions > Functions > Matrix > EXTREMA
float array[*][3] extrema(float array[*][*] table, integer column, boolean include_end_points = FALSE)
Returns a three-column array listing all local extrema in the specified column of table.
If the value in column column, row n of the table array is an extremum, the result table will contain a row with the following entries:
| Column # | Content | ||||||
| 1 | The value in column 1, row n of the table array. | ||||||
| 2 |
|
||||||
| 3 | The value in column column, row n of the table array. |
If include_end_points is TRUE, the first and last row of the table array are included in the result. By default, include_end_points is FALSE.
If no extrema are found, the result is an error (#VALUE!).
Examples
Given the array
_table = {{-1, 2, 3}, {-4, 5, 6}, {-7, 8, 7}, {-6, 5, 7}, {-3, 2, 1}}
the expression
=extrema(array(_table), 2)
returns {{-7, 1, 8}}. This tells us that, excluding the end points, column 2 of _table (values 2, 5, 8, 5, 2) contains one extremum: a local maximum (hence the 1 in the result) with value 8. It also tells us that in the table row containing this maximum, the value of column 1 is -7.
The expression
=extrema(array(_table), 1)
returns {{-7, -1, -7}}: again excluding the end points, column 1 of _table (values -1, -4, -7, -6, -3) contains a local minimum (hence the -1 in the result) with value -7.
The expression
=extrema(array(_table), 3)
returns {{-7, 0, 7}, {-6, 0, 7}}: still excluding the end points, column 3 of _table (values 3, 6, 7, 7, 1) contains two plateau points (hence the 0s in the result) with value 7, in the rows containing values -7 and -6 in column 1.
