public static Value largestOf(Value value1, Value value2) {
            if (value1 == DOUBLE || value2 == DOUBLE) return DOUBLE;
            if (value1 == FLOAT || value2 == FLOAT) return FLOAT;
            if (value1 == BFLOAT16 || value2 == BFLOAT16) return BFLOAT16;
            if (value1 == INT8 && value2 == INT8) return INT8;
            throw new IllegalArgumentException("Cannot find largest of "+value1+" and "+value2);
        }
The permissible cell value types. Default is double.
vespajlib/src/main/java/com/yahoo/tensor/TensorType.java