unstaged Readme file. Added common diff function

R/common_diff.R

@@ -0,0 +1,127 @@
+# NOT READY YET
+# find_common_diff <- function(.x,
+#                              type = "linear") {
+#
+#   stopifnot(is.sequence(.x) ||is.numeric(.x))
+#
+#   type <- match.arg(type,c("linear","quad","cubic","quart",
+#                            "quint","exp","circle","back",
+#                            "elastic","sine","bounce","step"))
+#   if(type == "linear"){
+#     m <- diff(.x)
+#     dif <- .x[2] - .x[1]
+#
+#     # Check if all elements are equal w/i given tolerance limits
+#     if(all(abs(m - dif)) < 1e-10){
+#       m <- m[1]
+#     } else {
+#       m <- get_mode(m)  # Mode of the differences if the sequence isn't regular
+#     }
+#
+#     seq_diff <- switch(
+#       type,
+#       quad = iterate_diff(x),
+#       cubic = iterate_diff(x),
+#       quartic = iterate_diff(x),
+#       quint = iterate_diff(x),
+#
+#     )
+#     return(m)
+#   }
+#
+# }
+
+#---- --- ---- --- ---- --- ---- --- ---- --- ---- --- ----#
+#' Find the Polynomial Degree of a Sequence
+#'
+#' This function determines the polynomial degree of a numeric sequence. The degree is determined by the number of times you must take differences of the sequence until you obtain a constant sequence (or a sequence that can no longer be differentiated).
+#'
+#' @param x A numeric vector or an object of class \code{Sequence}.
+#'   The sequence for which the polynomial degree is determined.
+#'
+#' @return An integer representing the degree of the polynomial. If the sequence is constant, the degree will be 0.
+#'
+#' @details
+#' The function repeatedly takes the differences of the input sequence until it becomes constant. The degree is incremented each time a new set of differences is computed.
+#'
+#' @examples
+#' find_polynomial_degree(c(1, 4, 9, 16))  # Output will be 2 (quadratic)
+#' find_polynomial_degree(c(2, 4, 6, 8))   # Output will be 1 (linear)
+#' find_polynomial_degree(c(5, 5, 5, 5))   # Output will be 0 (constant)
+#'
+#' @seealso \code{\link{iterate_diff}}
+#' @export
+#'
+find_polynomial_degree <- function(x) {
+
+  if(!is.numeric(x))
+    stop("Vector must be an object of class 'Sequence' or 'numeric'")
+
+  # Check if the input sequence is valid
+  if (length(x) < 2) {
+    stop("Sequence must have at least two elements.")
+  }
+
+  if (all_the_same(x)) {
+    return(0)  # Constant sequence
+  }
+
+  differences <- x
+  degree <- 1
+
+  while (length(differences) > 1) {
+    differences <- diff(differences)
+
+    # Check if the differences are constant
+    if (all_the_same(differences)) {
+      return(degree)
+    }
+    degree <- degree + 1
+  }
+
+  return(degree) # If all differences reduce to a single constant value
+}
+
+#---- --- ---- --- ---- --- ---- --- ---- --- ---- --- ----#
+#' Compute the Differences of a Sequence Based on Its Polynomial Degree
+#'
+#' This function computes the differences of a sequence iteratively based on the polynomial degree of the sequence. It first determines the degree of the sequence and then computes differences for that number of times.
+#'
+#' @param x A numeric vector or object of class \code{Sequence}.
+#'   The sequence for which the differences will be computed.
+#'
+#' @return A numeric vector representing the sequence after applying the differences iteratively according to its polynomial degree.
+#'
+#' @details
+#' The function first determines the polynomial degree of the input sequence using \code{\link{find_polynomial_degree}}. It then applies the \code{diff} function iteratively, the number of times corresponding to the degree of the sequence.
+#'
+#' @examples
+#' iterate_diff(c(1, 4, 9, 16))  # Output will be a sequence of differences after two iterations
+#' iterate_diff(c(2, 4, 6, 8))   # Output will be a sequence of differences after one iteration
+#' iterate_diff(c(5, 5, 5, 5))   # Output will be a constant sequence (no change)
+#'
+#' @seealso \code{\link{find_polynomial_degree}}
+#' @export
+iterate_diff <- function(x) {
+
+  stopifnot(is.numeric(x))
+
+  if(length(x) < 2)
+    stop("Sequence must have at least two elements.")
+
+  if (all_the_same(x)) {
+    return(x)  # Constant sequence
+  }
+
+  degree <- find_polynomial_degree(x)
+
+  # Compute differences 'degree' number of times
+  current_sequence <- x
+  for (i in seq_len(degree)) {
+    current_sequence <- diff(current_sequence)
+  }
+
+  return(current_sequence)
+}
+
+#---- --- ---- --- ---- --- ---- --- ---- --- ---- --- ----#

R/interpolate.R

@@ -78,6 +78,7 @@ interpolate <- function(data,
                            "quint","exp","circle","back",
                            "elastic","sine","bounce","step"))
 
+
   # Compute normalized time (t) as the y-component
   # Time could be any range, but it complicates comparison if
   # time range is not bounded. However, you can always
@@ -92,6 +93,9 @@ interpolate <- function(data,
     stop("Unsupported data type: data must be numeric, a data.frame, a matrix, or a list.")
   }
 
+  if(n <= 2)
+    stop("Data must be an object of length > 2")
+
   from <- min(data)
   to <- max(data)
 
@@ -274,5 +278,7 @@ interpolate <- function(data,
 
   smooth_seq <- from + smooth_fashion * (to-from)
 
-  return(smooth_seq)
+  Sequence(values = smooth_seq,
+           type = type,
+           ease = ease)
 }

R/seq_nl.R

@@ -88,6 +88,9 @@ stopifnot(is.character(type))
                            "quint","exp","circle","back",
                            "elastic","sine","bounce","step"))
 
+  if(n <= 2)
+    stop("'n' must be greater than 2")
+
   # Compute normalized time (t) as the y-component
   # Time could be any range, but it complicates comparison if
   # time range is not bounded. However, you can always
@@ -274,7 +277,8 @@ stopifnot(is.character(type))
 
  smooth_seq <- from + smooth_fashion * (to-from)
 
- Sequence(values = smooth_seq,
+  Sequence(values = smooth_seq,
           type = type,
           ease = ease)
+
 }