Nathaniel: Created page with "{{Function |name=update_odometer |desc=Increases a vector subject to limits on how large each entry can be |upd=December 11, 2014 |cat=List of functions#Helper_functions|Hel..."

2015-01-14T20:11:28Z

Created page with "{{Function |name=update_odometer |desc=Increases a vector subject to limits on how large each entry can be |upd=December 11, 2014 |cat=List of functions#Helper_functions|Hel..."

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{{Function
|name=update_odometer
|desc=Increases a vector subject to limits on how large each entry can be
|upd=December 11, 2014
|cat=[[List of functions#Helper_functions|Helper functions]]
|helper=1}}
<tt>'''update_odometer'''</tt> is a [[List of functions|function]] that implements an "odometer": that is, it increases the right-most entry of a vector by 1. If that right-most entry is now larger than its maximum allowed value then it "rolls over" to 0 and the second-to-right-most entry increases by 1. Similarly, if this entry is now too larger, it rolls over, and so on.

This function is useful if you are in a situation where you want to nest multiple <tt>for</tt> loops, but you don't know beforehand exactly how many of them there will be (since it depends on user input, for example).

==Syntax==
* <tt>NEW_IND = update_odometer(OLD_IND,UPPER_LIM)</tt>

==Argument descriptions==
* <tt>OLD_IND</tt>: The vector to be updated.
* <tt>UPPER_LIM</tt>: A vector of the same length as <tt>OLD_IND</tt> with the property that its <tt>j</tt>-th entry specifies the "roll over" value of the <tt>j</tt>-th entry of <tt>OLD_IND</tt>. That is, the <tt>j</tt>-th value of <tt>OLD_IND</tt> is constrained to being in the interval from <tt>0</tt> to <tt>UPPER_LIM(j)-1</tt> (inclusive).

==Examples==
The following code loops over all vectors of length 2 with the property that their first entry is 0, 1, or 2, and their second entry is 0 or 1:
<syntaxhighlight>
>> v = [0,0]; upper_lim = [3,2];
>> for j = 0:prod(upper_lim)-1
v = update_odometer(v,upper_lim)
end

v =

0 1

v =

1 0

v =

1 1

v =

2 0

v =

2 1

v =

0 0
</syntaxhighlight>

{{SourceCode|name=update_odometer|helper=1}}

Update odometer - Revision history

Nathaniel: Created page with "{{Function |name=update_odometer |desc=Increases a vector subject to limits on how large each entry can be |upd=December 11, 2014 |cat=List of functions#Helper_functions|Hel..."