Merge pull request #215 from kgoldfeld/fix_trtAssign

Fix trt assign

NEWS.md

@@ -1,5 +1,8 @@
 # simstudy (development version)
 
+## Breaking Changes
+* `trtAssign` with `ratio=NULL` used to produce 0-index values but 1-indexed values if `ratio` was set. This was adjusted so now both versions produce 0-indexed values. This is a potentially breaking change for existing scripts that use the generated treatment values while assuming the old behavior (e.g. using hardcoded values to filter).
+
 ## New features
 * Function `logisticCoefs` determines the intercept and treatment/exposure 
 parameter for a data generating process (based on a logistic regression model) 

R/group_data.R

@@ -362,7 +362,7 @@ trtAssign <- function(dtName, nTrt = 2, balanced = TRUE,
   assertNotMissing(dtName = missing(dtName))
   assertNotInDataTable(grpName, dtName)
   if (!is.null(ratio)) {
-    assertLengthEqual(var1 = length(ratio), var2 = nTrt)
+    assertEqual(nTrt = nTrt, val = length(ratio))
   }
 
   dt <- copy(dtName)
@@ -387,16 +387,14 @@ trtAssign <- function(dtName, nTrt = 2, balanced = TRUE,
   } else { # balanced is FALSE - strata are not relevant
 
     if (is.null(ratio)) {
-      if (nTrt == 2) {
-        formula <- .5
-      } else {
         formula <- rep(1 / nTrt, nTrt)
-      }
     } else { # ratio not null
       formula <- round(ratio / sum(ratio), 8)
     }
 
     dt <- trtObserve(dt, formulas = formula, logit.link = FALSE, grpName)
+    if (nTrt == 2) dt[, (grpName) := get(grpName) - 1]
+
   }
 
   return(dt[])
@@ -637,4 +635,4 @@ trtStepWedge <- function(dtName, clustID, nWaves, lenWaves,
 
   if (lag == 0) dd[, `:=`(xr = NULL)]
   return(dd[])
-}
+}