R/shift_origin.R

In peco: A Supervised Approach for **P**r**e**dicting **c**ell Cycle Pr**o**gression using scRNA-seq data

#' @name shift_origin
#'
#' @title Shift origin of the angles
#'
#' @description Shift origin of the angles for visualization
#'
#' @param phase A vector of angles (in radians).
#' @param origin the new origin of the angles.
#'
#' @return A vector of angles shifted to the new origin.
#'
#' @examples
#' # make a vector of angles
#' theta <- seq(0,2*pi, length.out=100)
#'
#' # shift the origin of theta to pi
#' theta_shifted <- shift_origin(theta, origin = pi)
#'
#' plot(x=theta, y = theta_shifted)
#'
#' @author Joyce Hsiao
#' @export
#'
shift_origin <- function(phase, origin) {
    phase2 <- phase
    if (origin > 0) {
    phase2[phase>=origin] <- phase[phase>=origin]-origin
    phase2[phase<origin] <- (phase[phase<origin]-origin+2*pi)
    }
    if (origin < 0) {
    a <- phase[phase >= 0 & phase< (2*pi-abs(origin))] + abs(origin)
    b <- -1*(2*pi - (phase[phase <= 2*pi & phase >= (2*pi - abs(origin))])) +
            abs(origin)
    phase2 <- c(a,b)
    }
    phase2
}