public final void put(int index, Value value) {
        values[index] = value.freeze();
        clearMissing(index);
        try {
            doubleValues()[index] = value.asDouble();
        }
        catch (UnsupportedOperationException e) {
            doubleValues()[index] = Double.NaN; // see getDouble below
        }
    }
Puts a value by index.
The value will be frozen if it isn't already.
searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/evaluation/ArrayContext.java