R/plotBoundary.R

In sglr: Sequential Generalized Likelihood Ratio Decision Boundaries Proposed by Shih, Lai, Heyse and Chen (2010, <doi:10.1002/Sim.4036>)

utils::globalVariables(c("lower", "upper", "y", "label"))

plotBoundary <- function(b1, b0, p, glrTables=NULL, tol=1e-7, legend=FALSE, textXOffset=2, textYSkip=2) {
  boundary <- computeBoundary(b1=b1, b0=b0, p=p, glrTables=glrTables)
  estimate <- boundary$estimate
  N <- length(boundary$upper)
  d <- data.frame(x=1:N, lower=boundary$lower, upper=boundary$upper)
  plot <- ggplot()
  plot <- plot + geom_step(aes(x=x, y=lower), data=d, colour="blue") + geom_step(aes(x=x, y=upper), data=d, colour = 'red')
  plot <- plot + theme(legend.position = "none")
  plot <- plot + scale_x_continuous('Total No. of AEs') + scale_y_continuous('No. of Vaccine AEs')
  x <- floor(sum(range(d$upper, na.rm=TRUE)/2))
  ## y1 <- ceiling((d$upper[length(d$upper)] + d$upper[x])/2)
  y1 <- d$upper[x] + 2
  plot <- plot + geom_text(aes(x, y, label=label), data=data.frame(x=floor(x/2), y=y1, label="Reject H_0"), color="red", hjust=0.0)
  y2 <- d$lower[x] - 2
  plot <- plot + geom_text(aes(x,y,label=label), data=data.frame(x=ceiling((x + length(d$upper))/2), y=y2, label="Accept H_0"), color="blue", hjust=0.0)

  if (legend) {
      leg1 <- paste("Hypothesis: (p[0] *\",\" * p[1]) * \"=\" * (", p[1], "* \",\" * ", p[2], ")", sep="")

      leg2 <- paste("SGLR *\" \" * Boundaries: (b[0] *\",\" * b[1]) * \"=\" * (", b0, "*\",\" * ", b1, ")", sep="")

      leg3 <- paste("Type *\" \" * I * \", \" * II * \" \" * Errors: (alpha *\", \"* beta) *\"=\" * (", round(estimate[1], 5), "*\", \" * ", round(estimate[2], 5), ")", sep="")

      leg4 <- paste("Max.* \" # of AEs N\"* \"=\" *", N, sep="")

      top <- max(d$upper, na.rm=TRUE)
      plot <- plot + geom_text(aes(x,y,label=label), data=data.frame(x=textXOffset, y=top, label=leg1), parse=TRUE, hjust=0.0)
      plot <- plot + geom_text(aes(x,y,label=label), data=data.frame(x=textXOffset, y=top-textYSkip, label=leg2), parse=TRUE, hjust=0.0)
      plot <- plot + geom_text(aes(x,y,label=label), data=data.frame(x=textXOffset, y=top-2*textYSkip, label=leg3), parse=TRUE, hjust=0.0)
      plot <- plot + geom_text(aes(x,y,label=label), data=data.frame(x=textXOffset, y=top-3*textYSkip, label=leg4), parse=TRUE, hjust=0.0)
  }

  plot
  ##   plot(1:N, pch="", xlab="Total number of AEs", ylab="Number of Vaccine AEs")
  ##   lines(1:N, boundary$upper, col="blue", pch=19, cex=.2, lty=2, type="b")
  ##   lines(1:N, boundary$lower, col="red", pch=19, cex=.2, lty=2, type="b")
}