Method is_identity

src/expr/src/linear.rs:110–115

True if the operator describes the identity transformation.

(&self)

    /// True if the operator describes the identity transformation.
    pub fn is_identity(&self) -> bool {
        self.expressions.is_empty()
            && self.predicates.is_empty()
            && self.projection.len() == self.input_arity
            && self.projection.iter().enumerate().all(|(i, p)| i == *p)
    }

    /// Retain only the indicated columns in the presented order.
    pub fn project<I>(mut self, columns: I) -> Self