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