View source for CumMin and CumMax

''New to [[Analytica 5.3]]''

[[Category:Transforming functions]]

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== CumMin(x, I'', passNull, reset{{Release|5.5||, window}}'') ==
== CumMax(x, I '', passNull, reset{{Release|5.5||, window}}'') ==

Returns an array with each element being the minimum or maximum of all preceding elements of «X» along dimension «I» up to, and including, the corresponding element of «X».

== Examples ==
:<code>I := </code>
::<code>1..7</code>
:<code>X := </code>
::<code>Array(I, [5, 2, 1, 8, -3, 0, 4])</code>
:<code>CumMin(X, I) &rarr;</code> 
::<code>[5, 2, 1, 1, -3, -3, -3]</code>   {indexed by <code>I</code>}
:<code>CumMax(X, I) &rarr;</code> 
::<code>[5, 5, 5, 8, 8, 8, 8]</code>   {indexed by <code>I</code>}

== Optional Parameters ==
=== PassNull ===
«PassNull» is an optional boolean parameter that defaults to <code>False</code>. When it is omitted or explicitly set to <code>False</code>, [[CumProduct]] ignores [[Null]] values.  In that case they have essentially the same effect as a one, unless they happen to be the first value in «X», in which case they are passed since no numeric values are yet obtained.

When «passNull» is explicitly set to true, then [[Null]] values are passed through as [[Null]] in the result.

:<code> J := 1..11</code>
:<code>X2 := </code>
::<code>Array(J, [Null, Null, 4, 2, Null, Null, 2, -1, 3, 2, Null])</code>
:<code>CumMin(X2, J) &rarr;</code>
::<code>[Null, Null, 4, 2, 2, 2, 2, -1, -1, -1, -1]</code>    { Indexed by <code>J</code> }
:<code>CumMin(X2, J, passNull: false) &rarr;</code>
::<code>[Null, Null, 4, 2, 2, 2, 2, -1, -1, -1, -1]</code>    { Indexed by <code>J</code> }
:<code>CumMin(X2, J, passNull: true) &rarr;</code>
::<code>[Null, Null, 4, 2, Null, Null, 2, -1, -1, -1, Null]</code>     { Indexed by <code>J</code> }
:<code>CumMax(X2, J, passNull: true) &rarr;</code>
::<code>[Null, Null, 4, 4, Null, Null, 4, 4, 4, 4, Null]</code>     { Indexed by <code>J</code> }

=== Reset ===
The optional «reset» parameter accepts an array of boolean values indexed by «I».  At the positions where «reset» is true, [[CumMin]] or [[CumMax]] starts over.  

:<code>I := </code>
::<code>[1, 2, 3, 4, 5, 6, 7]</code>
:<code>X := </code>
::<code>Array(I, [5, 2, 1, 8, -3, 7, 5])</code>
:<code>R := </code>
::<code>Array(I, [0, 0, 1, 0, 0, 1, 0])</code>
:<code>CumMin(X, I, reset: R) &rarr;</code> 
::<code>[5, 2, 1, 1, -3, 7, 5]</code>                { Indexed by <code>I</code> }
:<code>CumMax(X, I, reset: R) &rarr;</code> 
::<code>[5, 5, 1, 8, 8, 7, 7]</code>                { Indexed by <code>I</code> }

«Reset» can be used to restart the progressive min or max each time some state change occurs.  In such a scenario, the «reset» parameter is set to <code>True</code> at the first instant (along «I») that the system is in the new state.

=== Window ===
''New to [[Analytica 6.0]]''

When «window» is specified as a positive integer, does a windowed cum min or cum max. In other words, returns the minimum (or maximum) value among the most recent «window» points.

== See Also ==
* [[Min]], [[Max]]
* [[Cumulate]], [[CumProduct]]
* [[Dynamic]]