OpenMusic Reference
om-scale
om-scale
(arithmetic module) -- scales a list based on new maximum and minimum values
Syntax
om-scale self minout maxout &optional minin &optional maxin
Inputs
| name | data type(s) | comments |
|---|---|---|
| self | a tree | the list to be scaled |
| minout | a number | the target low number of the rescaled list |
| maxout | a number | the target high number of the rescaled list |
| minin | a number | optional; the virtual lower limit of the input list |
| maxin | a number | optional; the virtual upper limit of the input list |
Output
| output | data type(s) | comments |
|---|---|---|
| first | a tree | returns the tree self , rescaled |
Description
This function scales the values of elements in a list. The values minout and maxout specify the target minimum and maximum values for the new list. For example, the list (1 2 3 4 5) passed to om-scale with 1 and 9 as minimum and maximum values would return 1 3 5 7 9. Note that there is no requirement that the values be integers. om-scale maintains the relative distance between elements of the list.
The optional inputs minin and maxin are used to force om-scale to behave as if self had upper and lower values other than its lowest and highest values. This is useful in situations where the input list is a measurement on a preestablished scale- see the example.
If self is a nested list, a tree of identical dimensions is returned
Trees can also be rescaled with the om-scale/sum function.
Examples
Converting Fahrenheit to Celsius
This example illustrates one way to convert temperatures (or any other scaled data). The list of Fahrenheit temperatures (54 75 90 102) is passed to the function. 0 and 100 (the freezing and boiling points of water on the celsuis scale) are given as target values. The optional inputs are used to specify the equivalent values on the input (Fahrenheit) scale, since otherwise om-scale would assume that the lowest and highest values of the input list, i.e. 54 and 102, were equal to the low and high values specified at minout and maxout . om-round is used to convert the resulting fractional values into whole numbers- the list returned is (12 24 32 39)
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