[SYSTEMDS-3868] Fix missing function hoisting from if predicates

This patch adds the missing hoisting of DML function calls
(which always need to bind to variables) from basic if
predicates for convenience and in order to prevent
unexpected errors. Furthermore, this patch simplifies the
existing DML-bodied ampute() builtin by using this features
as well as call the existing sigmoid() instead of a custom one.

Author: mboehm7

scripts/builtin/ampute.dml

@@ -184,8 +184,7 @@ return (Matrix[Double] freq, Matrix[Double] patterns, Matrix[Double] weights) {
 u_handleDefaults = function(Matrix[Double] freq, Matrix[Double] patterns, Matrix[Double] weights, String mech, Integer numFeatures)
 return (Matrix[Double] freq, Matrix[Double] patterns, Matrix[Double] weights) {
   # Patterns: Default is a quadratic matrix wherein pattern i amputes feature i.
-  empty = u_isEmpty(patterns)
-  if (empty) { # FIX ME
+  if (u_isEmpty(patterns)) {
     patterns = matrix(1, rows=numFeatures, cols=numFeatures) - diag(matrix(1, rows=numFeatures, cols=1))
   }
 
@@ -205,8 +204,7 @@ return (Matrix[Double] freq, Matrix[Double] patterns, Matrix[Double] weights) {
   }
 
   # Frequencies: Uniform by default.
-  empty = u_isEmpty(freq) # FIX ME
-  if (empty) {
+  if (u_isEmpty(freq)) {
     freq = matrix(1 / numPatterns, rows=numPatterns, cols=1)
   }
 }
@@ -282,7 +280,7 @@ return (Matrix[Double] probsArray) {
   while (counter < maxIter & (is.na(currentProb) | abs(currentProb - prop) >= epsilon)) {
     counter += 1
     shift = lowerRange + (upperRange - lowerRange) / 2
-    probsArray = u_sigmoid(zScores + shift) # Calculates Right-Sigmoid probability (R implementation's default).
+    probsArray = sigmoid(zScores + shift) # Calculates Right-Sigmoid probability (R implementation's default).
     currentProb = mean(probsArray)
     if (currentProb - prop > 0) {
       upperRange = shift
@@ -293,11 +291,6 @@ return (Matrix[Double] probsArray) {
   }
 }
 
-u_sigmoid = function(Matrix[Double] X)
-return (Matrix[Double] sigmoided) {
-  sigmoided = 1 / (1 + exp(-X))
-}
-
 u_getBounds = function(Matrix[Double] numPerGroup, Integer groupSize, Integer patternNum)
 return(Integer start, Integer end) {
   if (patternNum == 1) {

src/main/java/org/apache/sysds/parser/StatementBlock.java

@@ -503,7 +503,12 @@ else if (current instanceof WhileStatementBlock) {
 		else if (current instanceof IfStatementBlock) {
 			IfStatementBlock isb = (IfStatementBlock) current;
 			IfStatement istmt = (IfStatement)isb.getStatement(0);
-			//TODO handle predicates
+			//handle predicate 
+			ArrayList<Statement> tmpPred = new ArrayList<>();
+			istmt.getConditionalPredicate().setPredicate(
+				rHoistFunctionCallsFromExpressions(
+					istmt.getConditionalPredicate().getPredicate(), false, tmpPred, prog));
+			//handle if and else body
 			ArrayList<StatementBlock> tmp = new ArrayList<>();
 			for (StatementBlock sb : istmt.getIfBody())
 				tmp.addAll(rHoistFunctionCallsFromExpressions(sb, prog));
@@ -514,6 +519,8 @@ else if (current instanceof IfStatementBlock) {
 					tmp2.addAll(rHoistFunctionCallsFromExpressions(sb, prog));
 				istmt.setElseBody(tmp2);
 			}
+			if( !tmpPred.isEmpty() )
+				return createStatementBlocks(current, tmpPred);
 		}
 		else if (current instanceof ForStatementBlock) { //incl parfor
 			ForStatementBlock fsb = (ForStatementBlock) current;