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