R glg中的ggplot将无法识别输入对象

Question

我正在制作一个模拟A / B测试的闪亮应用。我想输入参数并以图形方式显示测试。一切都很好，除了一件小事。向下滚动到下面的server.R的底部。我很确定ggplot中的输入$ Visitors出了问题。当我将其更改为访问者的默认值时，图表会显示并且可以正常工作。但是，我需要该值随滚动条而变化。有了这个，我得到这个错误＆＃34;错误在eval（expr，envir，enclos）：object＆＃39; input＆＃39;找不到＆＃34;。知道这里发生了什么吗？谢谢！！

ui.R

library(shiny)

# Define UI for application that draws a histogram
shinyUI(fluidPage(

  # Application title
  titlePanel("Optimizely AB Test"),

  # Sidebar with a slider input for the number of bins
  sidebarLayout(
    sidebarPanel(
      numericInput('Visitors', label = h3('Number of Visitors'), value=2000,
                 min = 0, max = 1000000),
      sliderInput("sliderX", label = h3("Conversion Rate in X"),value=.2,
            min = 0, max = 1),
        sliderInput("sliderY", label = h3("Conversion Rate in Y"),value=.1,
            min = 0, max = 1),
        numericInput('Tau', label = h3('Anticipated Variance'), value=.1,
                 min = 0, max = 1)
    ),
    mainPanel(
      plotOutput("ABInfo",width=800,height=600)
    )
  )
))

server.R

library(shiny)
library(ggplot2)

shinyServer(function(input, output) {
    output$ABInfo <- renderPlot({
          library(shiny)

              pretty_coversion=function(Xold,Yold,tau,num_visitors){
              #People in x and y
              nx=0
              ny=0
              #Conversions in x and y
              cx=0
              cy=0
              test=vector()
              diff=vector()
              for(i in 1:num_visitors){
                nx = nx + 1
                ny = ny + 1 
                #print(nx)
                if(runif(1,0,1) <= Xold){
                  cx=cx+1
                }
                #print(cx)
                if(runif(1,0,1) <= Yold){
                  cy=cy+1
                }
                #print(cy)
                Xn=cx/nx
                Yn=cy/ny
                diff[i]=abs(Xn-Yn)
                Vn=(Xn*(1-Xn)+Yn*(1-Yn))/(ny)
                #print(Vn)
                test_crit=((2*log(1/.05)-log(Vn/(Vn+tau)))*((Vn*(Vn+tau))/tau))^.5
                test[i]=test_crit
                #print(test[i])
              }
              x=data.frame(test[50:num_visitors],diff[50:num_visitors])
              colnames(x) = c("test","diff")
              return(x)

            }

  q=pretty_coversion(input$sliderX,input$sliderX,input$Tau,input$Visitors)
  s=ggplot(q, aes(x=50:input$Visitors)) +
      geom_line(aes(y=test), colour="red")+
      geom_line(aes(y=diff), colour="blue")+
      ylab(label="Difference in Conversion Rate")+
      xlab(label="Number of total visits")
  print(s)

    })
})