'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 if (is.numeric(index))
12 index = as.integer(index)
13 if (is.integer(index))
14 return (index) #works on integers too: trust input
15 if (inherits(index, "Date") || is.character(index))
16 {
17 tryCatch(indexAsDate <- as.Date(index), error=function(e) stop("Unrecognized index format"))
18 #TODO: tz arg to difftime ?
19 integerIndex <- round( as.numeric(
20 difftime(indexAsDate, as.Date(data$getTime(1)[1])) ) ) + 1
21 if (integerIndex >= 1 && integerIndex <= data$getSize())
22 return (integerIndex)
23 stop("Date outside data range")
24 }
25 stop("Unrecognized index format")
26 }
27
28 #' integerIndexToDate
29 #'
30 #' Transform an integer index to date index (relative to data)
31 #'
32 #' @param index Date (or integer) index
33 #' @param data Object of class \code{Data}
34 #'
35 #' @export
36 integerIndexToDate = function(index, data)
37 {
38 if (is(index,"Date"))
39 return (index) #works on dates too: trust input
40 index = index[1]
41 if (is.numeric(index))
42 index = as.integer(index)
43 if (!is.integer(index))
44 stop("'index' should be a date or integer")
45 as.Date( data$getTime(index)[1] )
46 }
47
48 #' getSimilarDaysIndices
49 #'
50 #' Find similar days indices in the past
51 #'
52 #' @param index Day index (numeric or date)
53 #' @param limit Maximum number of indices to return
54 #' @param same_seaon Should the indices correspond to day in same season?
55 #'
56 #' @export
57 getSimilarDaysIndices = function(index, limit, same_season)
58 {
59 index = dateIndexToInteger(index)
60
61 #TODO: mardi similaire à lundi mercredi jeudi aussi ...etc
62 if (!same_season)
63 {
64 #take all similar days in recent past
65 nb_days = min( (index-1) %/% 7, limit)
66 return ( rep(index,nb_days) - 7*seq_len(nb_days) )
67 }
68
69 #Look for similar days in similar season (+/- 30 days)
70 days = c()
71 i = index
72 while (i >= 1 && length(days) < limit)
73 {
74 if (i < index)
75 {
76 days = c(days, i)
77 #look in the "future of the past"
78 for (j in 1:4)
79 days = c(days, i+7*j)
80 }
81 #...and in the "past of the past"
82 for (j in 1:4)
83 {
84 if (i - 7*j >= 1)
85 days = c(days, i-7*j)
86 }
87 # TODO: exact computation instead of -364
88 # 364 = closest multiple of 7 to 365 - drift along the years... but not so many years so OK
89 i = i - 364
90 }
91
92 return ( days[1:min(limit,length(days))] )
93 }
94
95 #' getSerie
96 #'
97 #' Return a time-serie from its centered version + level
98 #'
99 #' @param data A list as returned by \code{getData}
100 #' @param index The index to return
101 #'
102 #' @export
103 getSerie = function(data, index)
104 data[[index]]$centered_serie + data[[index]]$level