##############################################################################################################################
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##R CODE FOR POP NEXT YEAR SHINY APP
##
##EDDIE HUNSINGER (AFFILIATION: ALASKA DEPARTMENT OF LABOR AND WORKFORCE DEVELOPMENT), MARCH 2017
##http://www.demog.berkeley.edu/~eddieh/
##edyhsgr@gmail.com
##
##THIS IS BASED ON R CODE AVAILABLE AT: https://plus.google.com/+AppliedDemographyToolbox/posts/TPFmUnch3tQ
##IF YOU WOULD LIKE TO USE, SHARE OR REPRODUCE ANY INFORMATION OR IDEAS FROM THIS WORK, BE SURE TO CITE THE SOURCE
##
##
##THE INPUTS USED HERE ARE NOT OFFICIAL OR CAREFULLY DEVELOPED, AND SHOULD ONLY BE USED FOR EXAMPLE
##THERE IS NO WARRANTY FOR THIS CODE
##THIS CODE HAS NOT BEEN CAREFULLY REVIEWED
##############################################################################################################################
##############################################################################################################################

library(shiny)
ui<-fluidPage(

	tags$h3("Alaska 2017 Population Possibilities Reviewer"),
	p("Related information and ",
	tags$a(href="https://www.r-project.org/", "R"),
	"code available at: ",
	tags$a(href="https://plus.google.com/+AppliedDemographyToolbox/posts/TPFmUnch3tQ", 
	"Applied Demography Toolbox Google+ post")
),
  
hr(),

sidebarLayout(
sidebarPanel(

	numericInput(inputId = "StartingPop",	
		label = "2016 population estimate",
		value = 739828, min = 0, max = 10000000000,width=250,step=100),

 sliderInput("Births", 
                label = "Births (uniform distribution)",
                min = 0, max = 20000, value = c(9000, 14000),step=100),

 sliderInput("Deaths", 
                label = "Deaths (uniform distribution)",
                min = 0, max = 10000, value = c(4000, 5000),step= 100),

 sliderInput("InMigration", 
                label = "In-migration (uniform distribution)",
                min = 0, max = 100000, value = c(30000,50000),step=1000),

	
 sliderInput("OutMigration", 
                label = "Out-migration (uniform distribution)",
                min = 0, max = 100000, value = c(40000,70000),step=1000),

tags$small(paste0(        
	"If graph is not visible, try edyhsgr.shinyapps.io/alaska2017.       
	This interface was made with Shiny for R (shiny.rstudio.com).       
	Eddie Hunsinger, March 2017."
	)),


width=3
),

mainPanel(
	
	plotOutput("plots"),width=3

))
)

server<-function(input, output) {	
	output$plots<-renderPlot({
par(mfrow=c(1,1))
	
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# Number of iterations
iter<-100000

# Starting population
StartingPop<-input$StartingPop

# Components of change for the period (year) 
# Uniform distribution guesses for components (iter, low bound, highbound)
Deaths<-runif(iter,input$Deaths[1],input$Deaths[2])
Births<-runif(iter,input$Births[1],input$Births[2])
InMigration<-runif(iter,input$InMigration[1],input$InMigration[2])
OutMigration<-runif(iter,input$OutMigration[1],input$OutMigration[2])

# Sampling
NextYearPop<-array(0,iter)
for(i in 1:iter){NextYearPop[i]<-(StartingPop - Deaths[i] 
+ Births[i] - OutMigration[i] + InMigration[i])}

# Output
#quantile(NextYearPop-StartingPop,c(.005,.05,.1,.25,.5,.75,.90,.95,.995))
#quantile(NextYearPop,c(.005,.05,.1,.25,.5,.75,.90,.95,.995))

#hist(NextYearPop-StartingPop)

hist(NextYearPop,50,main=paste("Histogram of 2017 Population (100,000 possibles)"),xlab = "2017 Population",col="lightgreen")

mtext(side=1,line=-31,adj=.025,text="Min: ",font=1,cex=1,col=1)
mtext(side=1,line=-31,adj=.25,text=round(quantile(NextYearPop,0),0),font=1,cex=1,col=1)
mtext(side=1,line=-30,adj=.025,text="5th Percentile: ",font=1,cex=1,col=1)
mtext(side=1,line=-30,adj=.25,text=round(quantile(NextYearPop,.05),0),font=1,cex=1,col=1)
mtext(side=1,line=-29,adj=.025,text="25th Percentile: ",font=1,cex=1,col=1)
mtext(side=1,line=-29,adj=.25,text=round(quantile(NextYearPop,.25),0),font=1,cex=1,col=1)
mtext(side=1,line=-28,adj=.025,text="Median: ",font=1,cex=1,col="red")
mtext(side=1,line=-28,adj=.25,text=round(quantile(NextYearPop,.5),0),font=1,cex=1,col="red")
mtext(side=1,line=-27,adj=.025,text="75th Percentile: ",font=1,cex=1,col=1)
mtext(side=1,line=-27,adj=.25,text=round(quantile(NextYearPop,.75),0),font=1,cex=1,col=1)
mtext(side=1,line=-26,adj=.025,text="95th Percentile: ",font=1,cex=1,col=1)
mtext(side=1,line=-26,adj=.25,text=round(quantile(NextYearPop,.95),0),font=1,cex=1,col=1)
mtext(side=1,line=-25,adj=.025,text="Max: ",font=1,cex=1,col=1)
mtext(side=1,line=-25,adj=.25,text=round(quantile(NextYearPop,1),0),font=1,cex=1,col=1)
},height=600,width=600)
		
}

shinyApp(ui = ui, server = server)