'update'
[talweg.git] / pkg / R / utils.R
CommitLineData
3a38473a
BA
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$getTime(index)[1] )
52}
53
54#' getSimilarDaysIndices
55#'
56#' Find similar days indices in the past; at least same type of day in the week:
57#' monday=tuesday=wednesday=thursday != friday != saturday != sunday.
58#'
59#' @param index Day index (numeric or date)
60#' @param data Reference dataset, object output of \code{getData}
61#' @param limit Maximum number of indices to return
62#' @param same_season Should the indices correspond to day in same season?
63#' @param days_in Optional set to intersect with results (NULL to discard)
64#' @param operational If TRUE: do not look for days after index (operational context)
65#'
66#' @export
67getSimilarDaysIndices = function(index, data, limit, same_season,
68 days_in=NULL, operational=TRUE)
69{
70 index = dateIndexToInteger(index, data)
71
72 # Look for similar days (optionally in same season)
73 days = c()
74 dt_ref = as.POSIXlt(data$getTime(index)[1]) #first date-time of current day
75 day_ref = dt_ref$wday #1=monday, ..., 6=saturday, 0=sunday
76 month_ref = as.POSIXlt(data$getTime(index)[1])$mon+1 #month in 1...12
77 i = index - 1
78 if (!operational)
79 j = index + 1
80 while (length(days) < min( limit, ifelse(is.null(days_in),Inf,length(days_in)) ))
81 {
82 if (i < 1 && j > data$getSize())
83 break
84 if (i >= 1)
85 {
86 dt = as.POSIXlt(data$getTime(i)[1])
87 if ((is.null(days_in) || i %in% days_in) && .isSameDay(dt$wday, day_ref))
88 {
89 if (!same_season || .isSameSeason(dt$mon+1, month_ref))
90 days = c(days, i)
91 }
92 i = i - 1
93 }
94 if (!operational && j <= data$getSize())
95 {
96 dt = as.POSIXlt(data$getTime(j)[1])
97 if ((is.null(days_in) || j %in% days_in) && .isSameDay(dt$wday, day_ref))
98 {
99 if (!same_season || .isSameSeason(dt$mon+1, month_ref))
100 days = c(days, j)
101 }
102 j = j + 1
103 }
104 }
105 return ( days )
106}
107
108# isSameSeason
109#
110# Check if two months fall in the same "season" (defined by estimated pollution rate).
111#
112# @param month Month index to test
113# @param month_ref Month to compare to
114#
115.isSameSeason = function(month, month_ref)
116{
117# if (month_ref == 3) #TODO: same as Bruno (but weird)
118# return (month %in% c(2,3,4,9,10))
119 if (month_ref %in% c(11,12,1,2)) #~= mid-polluted
120 return (month %in% c(11,12,1,2))
121 if (month_ref %in% c(3,4,9,10)) #~= high-polluted
122 return (month %in% c(3,4,9,10))
123 return (month %in% c(5,6,7,8)) #~= non polluted
124}
125
126# isSameDay
127#
128# Monday=Tuesday=Wednesday=Thursday ; Friday, Saturday, Sunday: specials.
129#
130# @param day Day index to test
131# @param day_ref Day index to compare to
132#
133.isSameDay = function(day, day_ref)
134{
135 if (day_ref %in% 1:4)
136 return (day %in% 1:4)
137 return (day == day_ref)
138}
139
140# getNoNA2
141#
142# Get indices in data of no-NA series preceded by no-NA, within [first,last] range.
143#
144# @inheritParams dateIndexToInteger
145# @param first First index (included)
146# @param last Last index (included)
147#
148.getNoNA2 = function(data, first, last)
149{
150 (first:last)[ sapply(first:last, function(i)
151 !any( is.na(data$getSerie(i-1)) | is.na(data$getSerie(i)) )
152 ) ]
153}