eventReactive, source() and plotting on R Shiny - r

Question

I am having some trouble with creating plots on eventReactive. I have a source code for inside event reactive, and I am trying to make multiple plots. I am a little unsure how to make multiple plots, so I tried to make one into a plot. However, I am still having trouble with this.
My ui and server are
library(shiny)
library(lpSolve)
ui <- fluidPage(
mainPanel(
tabsetPanel(
tabPanel("Information required for the model",
sliderInput("Reservoirs", label = h3("Total Number of Reservoirs"),
min = 1, max = 25,
value = 10),
sliderInput("Municipalities", label = h3("Total Number of Municipalities Served by the Reservoirs"),
min = 1, max = 150,
value = 15),
sliderInput("Time", label = h3("Total Number of Months for Future Decision"),
min = 0, max = 60,
value = 0)
),
tabPanel("Summary of csv files",
actionButton("Run_Model", "Run Model")),
tabPanel("Results",
plotOutput("plot_ipsita"),
img(outfile)
)
)))
server <- function(input, output) {
running_code<-eventReactive(input$Run_Model, {
source("Source_code.R", local=TRUE)
outfile <- tempfile(fileext = '.png')
png(outfile,width=30,height=nR*3,units = "in",res=200)
par(mfrow=c(ceiling(nR)/2, 2))
for (i in 1:nR){
hist(abcd[i,1,1])
}
dev.off()
plot((colSums(abcd[1,,])),type="l",ylab="Withdrawal [mio m3]",xlab = "months",col=1,lwd=3,lty=1)
abline(h=130, col = 2,lwd=3,lty=3)
abline(h=205, col=3, lwd=3,lty=4)
legend("topleft", c("","All Reservoirs","Import","Failure"), col = c(0,1,2,3),pt.cex=0.5,lty=1:4,lwd=3, cex=0.75,bty="n")
title(paste0("Withdrawals from reservoirs and imports and failure for % initial storage" ), cex.main=1)
})
output$plot_ipsita <- renderPlot({
running_code()
})
}
shinyApp(ui = ui, server = server)
And my source code is
nR<-input$Reservoirs
nM<-input$Municipalities
nT<-input$Time
abcd<-array(data=0, c(nR,nM,nT))
for (i in 1:nR){
abcd[i,,]<-(1+i)*55
}
My actual code is a lot more complicated, so I tried to simplify it to test with this one, and it does not seem happy. Nothing is running. However, if I try to run it as a regular R code, I am able to get all the results.
Please help!!!

Answer 1

The mistake in your code is in your ui where your sliderInput Time has a default value 0. This causes the following loop to fail not assigning any value to array abcd:
for (i in 1:nR){
abcd[i,,]<-(1+i)*55
}
Hence, colSums(abcd[1,,]) dos not have the value due to which it fails.
If you change the sliderInput("Time", label = h3("Total Number of Months for Future Decision"), min = 0, max = 60, value = 0) to sliderInput("Time", label = h3("Total Number of Months for Future Decision"), min = 0, max = 60, value = 2) your code creates a graph as follows:
Hope it helps!