Calculate a minimum for each period of INDEX. Essentially a rolling
application of minimum over a series of non-overlapping sections.
Usage
period.min(x, INDEX)
Value
An xts or zoo object of minimums, indexed by the period endpoints.
Arguments
x
a univariate data object
INDEX
a numeric vector of endpoints to calculate maximum on
Author
Jeffrey A. Ryan
Details
Used to calculate a minimum per period given an arbitrary
index of sections to be calculated over. This is an optimized function
for minimum. There are additional optimized versions for max, sum, and
prod.
For xts-coercible objects, an appropriate INDEX
can be derived from a call to endpoints.