'update'
[talweg.git] / pkg / R / utils.R
1 #' dateIndexToInteger
2 #'
3 #' Transform a (potential) date index into an integer (relative to data)
4 #'
5 #' @param index Date (or integer) index
6 #' @param data Object of class \code{Data}
7 #'
8 #' @export
9 dateIndexToInteger = 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), error=function(e) stop("Unrecognized index format"))
20 #TODO: tz arg to difftime ?
21 integerIndex <- round( as.numeric(
22 difftime(indexAsDate, as.Date(data$getTime(1)[1])) ) ) + 1
23 if (integerIndex >= 1 && integerIndex <= data$getSize())
24 return (integerIndex)
25 stop("Date outside data range")
26 }
27 stop("Unrecognized index format")
28 }
29
30 #' integerIndexToDate
31 #'
32 #' Transform an integer index to date index (relative to data)
33 #'
34 #' @param index Date (or integer) index
35 #' @param data Object of class \code{Data}
36 #'
37 #' @export
38 integerIndexToDate = 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$getTime(index)[1] )
52 }
53
54 #' getSimilarDaysIndices
55 #'
56 #' Find similar days indices in the past.
57 #'
58 #' @param index Day index (numeric or date)
59 #' @param data Reference dataset, object output of \code{getData}
60 #' @param limit Maximum number of indices to return
61 #' @param same_season Should the indices correspond to day in same season?
62 #' @param days_in Optional set to intersect with results (NULL to discard)
63 #'
64 #' @export
65 getSimilarDaysIndices = function(index, data, limit, same_season, days_in=NULL)
66 {
67 index = dateIndexToInteger(index, data)
68
69 # Look for similar days (optionally in same season)
70 i = index - 1
71 days = c()
72 dt_ref = as.POSIXlt(data$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])$mon+1 #month in 1...12
75 while (i >= 1 && length(days) < limit)
76 {
77 dt = as.POSIXlt(data$getTime(i)[1])
78 if ((is.null(days_in) || i %in% days_in) && .isSameDay(dt$wday, day_ref))
79 {
80 if (!same_season || .isSameSeason(dt$mon+1, month_ref))
81 days = c(days, i)
82 }
83 i = i - 1
84 }
85 return ( days )
86 }
87
88 # isSameSeason
89 #
90 # Check if two months fall in the same "season" (defined by estimated pollution rate)
91 #
92 # @param month month index to test
93 # @param month_ref month to compare to
94 #
95 .isSameSeason = function(month, month_ref)
96 {
97 if (month_ref %in% c(11,12,1,2)) #~= mid-polluted
98 return (month %in% c(11,12,1,2))
99 if (month_ref %in% c(3,4,9,10)) #~= high-polluted
100 return (month %in% c(3,4,9,10))
101 return (month %in% c(5,6,7,8)) #~= non polluted
102 }
103
104 # isSameDay
105 #
106 # Monday=Tuesday=Wednesday=Thursday ; Friday, Saturday, Sunday: specials
107 #
108 # @param day day index to test
109 # @param day_ref day index to compare to
110 #
111 .isSameDay = function(day, day_ref)
112 {
113 if (day_ref == 0)
114 return (day==0)
115 if (day_ref <= 4)
116 return (day <= 4)
117 return (day == day_ref)
118 }
119
120 #' getNoNA2
121 #'
122 #' Get indices in data of no-NA series followed by no-NA, within [first,last] range.
123 #'
124 #' @param data Object of class Data
125 #' @param first First index (included)
126 #' @param last Last index (included)
127 #'
128 #' @export
129 getNoNA2 = function(data, first, last)
130 {
131 (first:last)[ sapply(first:last, function(i)
132 !any( is.na(data$getCenteredSerie(i)) | is.na(data$getCenteredSerie(i+1)) )
133 ) ]
134 }