private TensorType outputType(TensorType givenType) {
        var builder = new TensorType.Builder(TensorType.Value.INT8);
        for (var d : givenType.dimensions())
            builder.dimension(d.size().isPresent() ? d.withSize((int) Math.ceil(d.size().get() / 8.0)) : d);
        return builder.build();
    }
Returns the type this produces from the given input type.
indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/PackBitsExpression.java