private$.params <- list("weights"=NA, "indices"=NA, "window"=NA)
# Do not forecast on days with NAs (TODO: softer condition...)
- if (any(is.na(data$getSerie(today-1)))
- || any(is.na(data$getSerie(today)[1:(predict_from-1)])))
+ if (any(is.na(data$getSerie(today-1))) ||
+ (predict_from>=2 && any(is.na(data$getSerie(today)[1:(predict_from-1)]))))
{
return (NA)
}
- # Determine indices of no-NAs days followed by no-NAs tomorrows
- fdays = .getNoNA2(data, max(today-memory,1), today-2)
+ # Determine indices of no-NAs days preceded by no-NAs yerstedays
+ tdays = .getNoNA2(data, max(today-memory,2), today-1)
# Get optional args
local = ifelse(hasArg("local"), list(...)$local, TRUE) #same level + season?
if (hasArg("window"))
{
return ( private$.predictShapeAux(data,
- fdays, today, predict_from, horizon, local, list(...)$window, simtype, TRUE) )
+ tdays, today, predict_from, horizon, local, list(...)$window, simtype, TRUE) )
}
# Indices of similar days for cross-validation; TODO: 20 = magic number
cv_days = getSimilarDaysIndices(today, data, limit=20, same_season=FALSE,
- days_in=fdays)
+ days_in=tdays)
# Optimize h : h |--> sum of prediction errors on last N "similar" days
errorOnLastNdays = function(window, simtype)
for (i in seq_along(cv_days))
{
# mix_strategy is never used here (simtype != "mix"), therefore left blank
- prediction = private$.predictShapeAux(data, fdays, cv_days[i], predict_from,
+ prediction = private$.predictShapeAux(data, tdays, cv_days[i], predict_from,
horizon, local, window, simtype, FALSE)
if (!is.na(prediction[1]))
{
nb_jours = nb_jours + 1
error = error +
- mean((data$getSerie(cv_days[i]+1)[predict_from:horizon] - prediction)^2)
+ mean((data$getSerie(cv_days[i])[predict_from:horizon] - prediction)^2)
}
}
return (error / nb_jours)
else #none: value doesn't matter
1
- return( private$.predictShapeAux(data, fdays, today, predict_from, horizon, local,
+ return( private$.predictShapeAux(data, tdays, today, predict_from, horizon, local,
best_window, simtype, TRUE) )
}
),
private = list(
# Precondition: "today" is full (no NAs)
- .predictShapeAux = function(data, fdays, today, predict_from, horizon, local, window,
+ .predictShapeAux = function(data, tdays, today, predict_from, horizon, local, window,
simtype, final_call)
{
- fdays_cut = fdays[ fdays < today ]
- if (length(fdays_cut) <= 1)
+ tdays_cut = tdays[ tdays <= today-1 ]
+ if (length(tdays_cut) <= 1)
return (NA)
if (local)
{
# TODO: 60 == magic number
- fdays = getSimilarDaysIndices(today, data, limit=60, same_season=TRUE,
- days_in=fdays_cut)
- if (length(fdays) <= 1)
+ tdays = getSimilarDaysIndices(today, data, limit=60, same_season=TRUE,
+ days_in=tdays_cut)
+ if (length(tdays) <= 1)
return (NA)
# TODO: 10, 12 == magic numbers
- fdays = .getConstrainedNeighbs(today,data,fdays,min_neighbs=10,max_neighbs=12)
- if (length(fdays) == 1)
+ tdays = .getConstrainedNeighbs(today,data,tdays,min_neighbs=10,max_neighbs=12)
+ if (length(tdays) == 1)
{
if (final_call)
{
private$.params$weights <- 1
- private$.params$indices <- fdays
+ private$.params$indices <- tdays
private$.params$window <- 1
}
- return ( data$getSerie(fdays[1]+1)[predict_from:horizon] )
+ return ( data$getSerie(tdays[1])[predict_from:horizon] )
}
}
else
- fdays = fdays_cut #no conditioning
+ tdays = tdays_cut #no conditioning
if (simtype == "endo" || simtype == "mix")
{
window_endo = ifelse(simtype=="mix", window[1], window)
# Distances from last observed day to days in the past
- lastSerie = c( data$getSerie(today-1), data$getSerie(today)[1:(predict_from-1)] )
- distances2 = sapply(fdays, function(i) {
- delta = lastSerie - c(data$getSerie(i),data$getSerie(i+1)[1:(predict_from-1)])
+ lastSerie = c( data$getSerie(today-1),
+ data$getSerie(today)[if (predict_from>=2) 1:(predict_from-1) else c()] )
+ distances2 = sapply(tdays, function(i) {
+ delta = lastSerie - c(data$getSerie(i-1),
+ data$getSerie(i)[if (predict_from>=2) 1:(predict_from-1) else c()])
sqrt(mean(delta^2))
})
# Compute exogen similarities using given window
window_exo = ifelse(simtype=="mix", window[2], window)
- M = matrix( ncol=1+length(fdays), nrow=1+length(data$getExo(1)) )
+ M = matrix( ncol=1+length(tdays), nrow=1+length(data$getExo(1)) )
M[,1] = c( data$getLevelHat(today), as.double(data$getExoHat(today)) )
- for (i in seq_along(fdays))
- M[,i+1] = c( data$getLevel(fdays[i]), as.double(data$getExo(fdays[i])) )
+ for (i in seq_along(tdays))
+ M[,i+1] = c( data$getLevel(tdays[i]), as.double(data$getExo(tdays[i])) )
sigma = cov(t(M)) #NOTE: robust covariance is way too slow
# TODO: 10 == magic number; more robust way == det, or always ginv()
sigma_inv =
- if (length(fdays) > 10)
+ if (length(tdays) > 10)
solve(sigma)
else
MASS::ginv(sigma)
# Distances from last observed day to days in the past
- distances2 = sapply(seq_along(fdays), function(i) {
+ distances2 = sapply(seq_along(tdays), function(i) {
delta = M[,1] - M[,i+1]
delta %*% sigma_inv %*% delta
})
else if (simtype == "mix")
simils_endo * simils_exo
else #none
- rep(1, length(fdays))
+ rep(1, length(tdays))
similarities = similarities / sum(similarities)
prediction = rep(0, horizon-predict_from+1)
- for (i in seq_along(fdays))
+ for (i in seq_along(tdays))
{
prediction = prediction +
- similarities[i] * data$getSerie(fdays[i]+1)[predict_from:horizon]
+ similarities[i] * data$getSerie(tdays[i])[predict_from:horizon]
}
if (final_call)
{
private$.params$weights <- similarities
- private$.params$indices <- fdays
+ private$.params$indices <- tdays
private$.params$window <-
if (simtype=="endo")
window_endo
#
# @param today Index of current day
# @param data Object of class Data
-# @param fdays Current set of "first days" (no-NA pairs)
+# @param tdays Current set of "second days" (no-NA pairs)
# @param min_neighbs Minimum number of points in a neighborhood
# @param max_neighbs Maximum number of points in a neighborhood
#
-.getConstrainedNeighbs = function(today, data, fdays, min_neighbs=10, max_neighbs=12)
+.getConstrainedNeighbs = function(today, data, tdays, min_neighbs=10, max_neighbs=12)
{
levelToday = data$getLevelHat(today)
levelYersteday = data$getLevel(today-1)
- distances = sapply(fdays, function(i) {
- sqrt((data$getLevel(i)-levelYersteday)^2 + (data$getLevel(i+1)-levelToday)^2)
+ distances = sapply(tdays, function(i) {
+ sqrt((data$getLevel(i-1)-levelYersteday)^2 + (data$getLevel(i)-levelToday)^2)
})
#TODO: 1, +1, +3 : magic numbers
dist_thresh = 1
- min_neighbs = min(min_neighbs,length(fdays))
+ min_neighbs = min(min_neighbs,length(tdays))
repeat
{
same_pollution = (distances <= dist_thresh)
break
dist_thresh = dist_thresh + ifelse(dist_thresh>1,3,1)
}
- fdays = fdays[same_pollution]
+ tdays = tdays[same_pollution]
max_neighbs = 12
if (nb_neighbs > max_neighbs)
{
# Keep only max_neighbs closest neighbors
- fdays = fdays[ order(distances[same_pollution])[1:max_neighbs] ]
+ tdays = tdays[ order(distances[same_pollution])[1:max_neighbs] ]
}
- fdays
+ tdays
}
# compute similarities