fix tests
[talweg.git] / pkg / R / utils.R
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1#' dateIndexToInteger
2#'
3#' Transform a (potential) date index into an integer (relative to data beginning).
4#'
5#' @param index Date (or integer) index
6#' @param data Object of class Data, output of \code{getData()}
7#'
8#' @export
9dateIndexToInteger = function(index, data)
10{
11 # Works on integers too: trust input
12 if (is.numeric(index))
13 index = as.integer(index)
14 if (is.integer(index))
15 return (index)
16
17 if (inherits(index, "Date") || is.character(index))
18 {
19 tryCatch(indexAsDate <- as.Date(index),
20 error=function(e) stop("Unrecognized index format"))
21 #TODO: tz arg to difftime ?
22 integerIndex <- round( as.numeric(
23 difftime(indexAsDate, as.Date(data$getTime(1)[1])) ) ) + 1
24 if (integerIndex >= 1 && integerIndex <= data$getSize())
25 return (integerIndex)
26 stop("Date outside data range")
27 }
28 stop("Unrecognized index format")
29}
30
31#' integerIndexToDate
32#'
33#' Transform an integer index (relative to data beginning) into a date index.
34#'
35#' @inheritParams dateIndexToInteger
36#'
37#' @export
38integerIndexToDate = function(index, data)
39{
40 # Works on dates too: trust input
41 if (is.character(index))
42 index = as.Date(index)
43 if (is(index,"Date"))
44 return (index)
45
46 index = index[1]
47 if (is.numeric(index))
48 index = as.integer(index)
49 if (!is.integer(index))
50 stop("'index' should be a date or integer")
51 as.Date( data$getTime(index)[1] )
52}
53
54#' getSimilarDaysIndices
55#'
56#' Find similar days indices in the past; at least same type of day in the week:
57#' monday=tuesday=wednesday=thursday != friday != saturday != sunday.
58#'
59#' @param index Day index (numeric or date)
60#' @param data Reference dataset, object output of \code{getData}
61#' @param limit Maximum number of indices to return
62#' @param same_season Should the indices correspond to day in same season?
63#' @param days_in Optional set to intersect with results (NULL to discard)
64#'
65#' @export
66getSimilarDaysIndices = function(index, data, limit, same_season, days_in=NULL)
67{
68 index = dateIndexToInteger(index, data)
69
70 # Look for similar days (optionally in same season)
71 days = c()
72 dt_ref = as.POSIXlt(data$getTime(index)[1]) #first date-time of current day
73 day_ref = dt_ref$wday #1=monday, ..., 6=saturday, 0=sunday
74 month_ref = as.POSIXlt(data$getTime(index)[1])$mon+1 #month in 1...12
75 i = index - 1
76 while (i >= 1 && length(days) < limit)
77 {
78 dt = as.POSIXlt(data$getTime(i)[1])
79 if ((is.null(days_in) || i %in% days_in) && .isSameDay(dt$wday, day_ref))
80 {
81 if (!same_season || .isSameSeason(dt$mon+1, month_ref))
82 days = c(days, i)
83 }
84 i = i - 1
85 }
86 return ( days )
87}
88
89# isSameSeason
90#
91# Check if two months fall in the same "season" (defined by estimated pollution rate).
92#
93# @param month Month index to test
94# @param month_ref Month to compare to
95#
96.isSameSeason = function(month, month_ref)
97{
98 if (month_ref %in% c(11,12,1,2)) #~= mid-polluted
99 return (month %in% c(11,12,1,2))
100 if (month_ref %in% c(3,4,9,10)) #~= high-polluted
101 return (month %in% c(3,4,9,10))
102 return (month %in% c(5,6,7,8)) #~= non polluted
103}
104
105# isSameDay
106#
107# Monday=Tuesday=Wednesday=Thursday ; Friday, Saturday, Sunday: specials.
108#
109# @param day Day index to test
110# @param day_ref Day index to compare to
111#
112.isSameDay = function(day, day_ref)
113{
114 if (day_ref %in% 1:4)
115 return (day %in% 1:4)
116 return (day == day_ref)
117}