Add Java ranking power operator

7 files changed, 36 insertions, 7 deletions

diff --git a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/DoubleCompatibleValue.java b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/DoubleCompatibleValue.java
index 0868af9bc72..ea750295423 100644
--- a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/DoubleCompatibleValue.java
+++ b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/DoubleCompatibleValue.java
@@ -59,6 +59,11 @@ public abstract class DoubleCompatibleValue extends Value {
     }
 
     @Override
+    public Value power(Value value) {
+        return new DoubleValue(Function.pow.evaluate(asDouble(), value.asDouble()));
+    }
+
+    @Override
     public Value compare(TruthOperator operator, Value value) {
         return new BooleanValue(operator.evaluate(asDouble(), value.asDouble()));
     }
diff --git a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/StringValue.java b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/StringValue.java
index b62081f2c6a..ac8aba6a617 100644
--- a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/StringValue.java
+++ b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/StringValue.java
@@ -88,6 +88,11 @@ public class StringValue extends Value {
     }
 
     @Override
+    public Value power(Value value) {
+        throw new UnsupportedOperationException("String values ('" + value + "') do not support ^");
+    }
+
+    @Override
     public Value compare(TruthOperator operator, Value value) {
         if (operator.equals(TruthOperator.EQUAL))
             return new BooleanValue(this.equals(value));
diff --git a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/TensorValue.java b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/TensorValue.java
index 919a23eeaf5..49c3ccb7b01 100644
--- a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/TensorValue.java
+++ b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/TensorValue.java
@@ -110,6 +110,14 @@ public class TensorValue extends Value {
         return new TensorValue(value.map((value) -> (value==0.0) ? 1.0 : 0.0));
     }
 
+    @Override
+    public Value power(Value argument) {
+        if (argument instanceof TensorValue)
+            return new TensorValue(value.pow(((TensorValue)argument).value));
+        else
+            return new TensorValue(value.map((value) -> Math.pow(value, argument.asDouble())));
+    }
+
     private Tensor asTensor(Value value, String operationName) {
         if ( ! (value instanceof TensorValue))
             throw new UnsupportedOperationException("Could not perform " + operationName +
diff --git a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/Value.java b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/Value.java
index bcbce6e646f..b2ccbe572d0 100644
--- a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/Value.java
+++ b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/Value.java
@@ -49,6 +49,8 @@ public abstract class Value {
 
     public abstract Value not();
 
+    public abstract Value power(Value value);
+
     /** Perform the comparison specified by the operator between this value and the given value */
     public abstract Value compare(TruthOperator operator, Value value);
 
diff --git a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/rule/ArithmeticOperator.java b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/rule/ArithmeticOperator.java
index aae59fe2af8..a715490e95a 100644
--- a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/rule/ArithmeticOperator.java
+++ b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/rule/ArithmeticOperator.java
@@ -34,6 +34,9 @@ public enum ArithmeticOperator {
     }},
     MODULO(6, "%") { public Value evaluate(Value x, Value y) {
         return x.modulo(y);
+    }},
+    POWER(7, "^") { public Value evaluate(Value x, Value y) {
+        return x.power(y);
     }};
 
     /** A list of all the operators in this in order of decreasing precedence */
@@ -61,6 +64,7 @@ public enum ArithmeticOperator {
 
     private static List<ArithmeticOperator> operatorsByPrecedence() {
         List<ArithmeticOperator> operators = new ArrayList<>();
+        operators.add(POWER);
         operators.add(MODULO);
         operators.add(DIVIDE);
         operators.add(MULTIPLY);
diff --git a/searchlib/src/main/javacc/RankingExpressionParser.jj b/searchlib/src/main/javacc/RankingExpressionParser.jj
index 035a92b0365..7821ab88b86 100755
--- a/searchlib/src/main/javacc/RankingExpressionParser.jj
+++ b/searchlib/src/main/javacc/RankingExpressionParser.jj
@@ -66,6 +66,7 @@ TOKEN :
     <MUL: "*"> |
     <DOT: "."> |
     <MOD: "%"> |
+    <POWOP: "^"> |
 
     <DOLLAR: "$"> |
     <COMMA: ","> |
@@ -204,13 +205,14 @@ ExpressionNode arithmeticExpression() :
 
 ArithmeticOperator arithmetic() : { }
 {
-    ( <ADD> { return ArithmeticOperator.PLUS;     } |
-      <SUB> { return ArithmeticOperator.MINUS;    } |
-      <DIV> { return ArithmeticOperator.DIVIDE;   } |
-      <MUL> { return ArithmeticOperator.MULTIPLY; } |
-      <MOD> { return ArithmeticOperator.MODULO; }   |
-      <AND> { return ArithmeticOperator.AND; }      |
-      <OR>  { return ArithmeticOperator.OR; } )
+    ( <ADD>   { return ArithmeticOperator.PLUS;     } |
+      <SUB>   { return ArithmeticOperator.MINUS;    } |
+      <DIV>   { return ArithmeticOperator.DIVIDE;   } |
+      <MUL>   { return ArithmeticOperator.MULTIPLY; } |
+      <MOD>   { return ArithmeticOperator.MODULO; }   |
+      <AND>   { return ArithmeticOperator.AND; }      |
+      <OR>    { return ArithmeticOperator.OR; }       |
+      <POWOP> { return ArithmeticOperator.POWER; } )
     { return null; }
 }
 
diff --git a/searchlib/src/test/java/com/yahoo/searchlib/rankingexpression/evaluation/EvaluationTestCase.java b/searchlib/src/test/java/com/yahoo/searchlib/rankingexpression/evaluation/EvaluationTestCase.java
index 26d3695dd07..8e34f35245d 100644
--- a/searchlib/src/test/java/com/yahoo/searchlib/rankingexpression/evaluation/EvaluationTestCase.java
+++ b/searchlib/src/test/java/com/yahoo/searchlib/rankingexpression/evaluation/EvaluationTestCase.java
@@ -29,6 +29,7 @@ public class EvaluationTestCase {
         tester.assertEvaluates(0.75, "0.5 + 0.25");
         tester.assertEvaluates(0.75, "one_half + a_quarter");
         tester.assertEvaluates(1.25, "0.5 - 0.25 + one");
+        tester.assertEvaluates(9.0, "3 ^ 2");
 
         // String
         tester.assertEvaluates(1, "if(\"a\"==\"a\",1,0)");
@@ -38,6 +39,8 @@ public class EvaluationTestCase {
         tester.assertEvaluates(1, "2/6+4/6");
         tester.assertEvaluates(2 * 3 * 4 + 3 * 4 * 5 - 4 * 200 / 10, "2*3*4+3*4*5-4*200/10");
         tester.assertEvaluates(3, "1 + 10 % 6 / 2");
+        tester.assertEvaluates(10.0, "3 ^ 2 + 1");
+        tester.assertEvaluates(18.0, "2 * 3 ^ 2");
 
         // Conditionals
         tester.assertEvaluates(2 * (3 * 4 + 3) * (4 * 5 - 4 * 200) / 10, "2*(3*4+3)*(4*5-4*200)/10");