R/Phase2.R

In sascha2schroeder/popEye: Analysis of eye-tracking data from reading experiments

Phase2 <- function(fix, stimmat, check = FALSE) {
  
  # message(paste(".... Phase 2"))
  
  crit1 <- mean((stimmat$ye[stimmat$line == 1] - stimmat$ys[stimmat$line == 1])) / 4
  crit2 <- mean((stimmat$ye[stimmat$line == 1] - stimmat$ys[stimmat$line == 1])) / 4
  
  old <- length(table(fix$linerun)) + 1
  new <- length(table(fix$linerun))
  
  while (new < old) {
    
    if (check == TRUE) {
      ReadKey()
    }
    
    old <- new
    out <- NULL
    
    long <- as.numeric(unlist(dimnames(table(fix$linerun)[table(fix$linerun) >= 3])))
    
    if (length(long) == 0) {
      break
    }
    
    for (i in 1:(length(long) - 1)) {
      # i <- 1
      # print(i)
      
      for (j in 1:length(long)) {
        # j <- i + 1
        # print(j)
        
        # exclude diagonal elements
        if (i == j) {
          next
        }
        
        # exclude symmetric elements
        if (is.element(paste(i, j), paste(out[, 2], out[,1]))) {
          next
        }
        
        # # if long runs are not adjecent
        # if (long[j] != (long[i] + 1)) {
        #   next
        # }
        
        tmp <- matrix(NA, 1, 5)
        
        tmp[1, 1] <- long[i]
        tmp[1, 2] <- long[j]
        
        # compute regressions
        fm <- lm(fix$yn[fix$linerun == long[i] | fix$linerun == long[j]] ~ 
                   scale(fix$xn[fix$linerun == long[i] | fix$linerun == long[j]]))
        tmp[1, 3] <- round(sigma(fm))
        tmp[1, 4] <- round(coef(fm)[1])
        tmp[1, 5] <- round(coef(fm)[2])
        
        out <- rbind(out, tmp)
        
      }
      
    }
    
    if(is.null(out)) {
      next
    }
    
    # select candidate
    out2 <- out[order(abs(out[, 5])), , drop = F]
    
    if (sum(out2[,3] < crit1 & abs(out2[,5]) < crit2) < 1) {
      break
    } else if (sum(out2[,3] < crit1 & abs(out2[,5]) < crit2) == 1) {
      cand <- out2[out2[,3] < crit1 & abs(out2[,5]) < crit2, ]
    } else if (sum(out2[,3] < crit1 & abs(out2[,5]) < crit2) > 1) {
      cand <- out2[out2[,3] < crit1 & abs(out2[,5]) < crit2, ][1, ]
    }
    
    if (check == TRUE) {
      plot(fix$xn, fix$yn, ylim = c(768, 0), type = "l", main = paste(cand[1], ":", cand[2]))
      points(fix$xn[fix$linerun == cand[1]], fix$yn[fix$linerun == cand[1]], 
             col = "green", pch = 16, type = "b", cex = 1, lty = 1)
      points(fix$xn[fix$linerun == cand[2]], fix$yn[fix$linerun == cand[2]], 
             col = "red", pch = 16, type = "b", cex = 1, lty = 1)
      abline(lm(fix$yn[fix$linerun == cand[1] | fix$linerun == cand[2]] ~ 
                  (fix$xn[fix$linerun == cand[1] | fix$linerun == cand[2]])))
    }
    
    fix$linerun[fix$linerun == cand[2]] <- cand[1]
    fix$linerun <- as.numeric(as.factor(fix$linerun))
    
    new <- length(table(fix$linerun))
    # print(new)
    
  }
  
  return(fix)
  
}