1 files changed, 53 insertions, 0 deletions
diff --git a/vespajlib/src/main/java/com/yahoo/tensor/functions/Random.java b/vespajlib/src/main/java/com/yahoo/tensor/functions/Random.java
new file mode 100644
index 00000000000..ba34c0d9748
--- /dev/null
+++ b/vespajlib/src/main/java/com/yahoo/tensor/functions/Random.java
@@ -0,0 +1,53 @@
+package com.yahoo.tensor.functions;
+
+import com.yahoo.tensor.TensorType;
+import com.yahoo.tensor.functions.CompositeTensorFunction;
+import com.yahoo.tensor.functions.Generate;
+import com.yahoo.tensor.functions.PrimitiveTensorFunction;
+import com.yahoo.tensor.functions.ScalarFunctions;
+import com.yahoo.tensor.functions.TensorFunction;
+import com.yahoo.tensor.functions.ToStringContext;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * A tensor generator which returns a tensor of any dimension filled with random numbers between 0 and 1.
+ *
+ * @author bratseth
+ */
+public class Random extends CompositeTensorFunction {
+
+    private final TensorType type;
+    
+    public Random(TensorType type) {
+        this.type = type;
+    }
+    
+    @Override
+    public List<TensorFunction> functionArguments() { return Collections.emptyList(); }
+
+    @Override
+    public TensorFunction replaceArguments(List<TensorFunction> arguments) {
+        if ( arguments.size() != 1)
+            throw new IllegalArgumentException("Random must have 0 arguments, got " + arguments.size());
+        return this;
+    }
+
+    @Override
+    public PrimitiveTensorFunction toPrimitive() {
+        return new Generate(type, ScalarFunctions.random());
+    }
+
+    @Override
+    public String toString(ToStringContext context) {
+        return "random(" + dimensionNames().collect(Collectors.joining(",")) + ")";
+    }
+    
+    private Stream<String> dimensionNames() {
+        return type.dimensions().stream().map(TensorType.Dimension::toString);
+    }
+
+}