plot DAG for negative control variable using R

dag_negativecontrol.R

library(DiagrammeR)
library(DiagrammeRsvg)
library(rsvg)
g1 <- grViz("digraph{
                     node[shape = plaintext]
                     U[label = 'U']
                     L[label = 'L']
                     A[label = 'A']
                     Y[label = 'Y']
                     U -> L[arrowhead=none, style=dashed]
                     U -> A
                     L -> A
                     A -> Y
                     U -> Y
                     L -> Y
                     }")
print(g1)

rsvg_png(charToRaw(export_svg(g1)), 
         "graph1.png",
         width = 500, height = 500)

g2 <- grViz("digraph{
                     node[shape = plaintext]
                     U[label = 'U']
                     L[label = 'L']
                     A[label = 'A']
                     Y[label = 'Y']
                     U -> L[arrowhead=none, style=dashed]
                     U -> N
                     L -> N
                     U -> A
                     L -> A
                     A -> Y
                     U -> Y
                     L -> Y
                     }")
print(g2)
rsvg_png(charToRaw(export_svg(g2)), 
         "graph2.png",
         width = 500, height = 500)