Struct datafusion_physical_expr::intervals::cp_solver::ExprIntervalGraph

pub struct ExprIntervalGraph { /* private fields */ }

This object implements a directed acyclic expression graph (DAEG) that is used to compute ranges for expressions through interval arithmetic.

Implementations

impl ExprIntervalGraph

pub fn size(&self) -> usize

Estimate size of bytes including Self.

impl ExprIntervalGraph

pub fn try_new(expr: Arc<dyn PhysicalExpr>, schema: &Schema) -> Result<Self>

pub fn node_count(&self) -> usize

pub fn gather_node_indices( &mut self, exprs: &[Arc<dyn PhysicalExpr>], ) -> Vec<(Arc<dyn PhysicalExpr>, usize)>

This function associates stable node indices with PhysicalExprs so that we can match Arc<dyn PhysicalExpr> and NodeIndex objects during membership tests.

pub fn update_ranges( &mut self, leaf_bounds: &mut [(usize, Interval)], given_range: Interval, ) -> Result<PropagationResult>

Updates intervals for all expressions in the DAEG by successive bottom-up and top-down traversals.

pub fn assign_intervals(&mut self, assignments: &[(usize, Interval)])

This function assigns given ranges to expressions in the DAEG. The argument assignments associates indices of sought expressions with their corresponding new ranges.

pub fn update_intervals(&self, assignments: &mut [(usize, Interval)])

This function fetches ranges of expressions from the DAEG. The argument assignments associates indices of sought expressions with their ranges, which this function modifies to reflect the intervals in the DAEG.

pub fn evaluate_bounds(&mut self) -> Result<&Interval>

Computes bounds for an expression using interval arithmetic via a bottom-up traversal.

Arguments

• leaf_bounds - &[(usize, Interval)]. Provide NodeIndex, Interval tuples for leaf variables.

Examples

use arrow::datatypes::DataType;
use arrow::datatypes::Field;
use arrow::datatypes::Schema;
use datafusion_common::ScalarValue;
use datafusion_expr::interval_arithmetic::Interval;
use datafusion_expr::Operator;
use datafusion_physical_expr::expressions::{BinaryExpr, Column, Literal};
use datafusion_physical_expr::intervals::cp_solver::ExprIntervalGraph;
use datafusion_physical_expr::PhysicalExpr;
use std::sync::Arc;

let expr = Arc::new(BinaryExpr::new(
    Arc::new(Column::new("gnz", 0)),
    Operator::Plus,
    Arc::new(Literal::new(ScalarValue::Int32(Some(10)))),
));

let schema = Schema::new(vec![Field::new("gnz".to_string(), DataType::Int32, true)]);

let mut graph = ExprIntervalGraph::try_new(expr, &schema).unwrap();
// Do it once, while constructing.
let node_indices = graph
    .gather_node_indices(&[Arc::new(Column::new("gnz", 0))]);
let left_index = node_indices.get(0).unwrap().1;

// Provide intervals for leaf variables (here, there is only one).
let intervals = vec![(
    left_index,
    Interval::make(Some(10), Some(20)).unwrap(),
)];

// Evaluate bounds for the composite expression:
graph.assign_intervals(&intervals);
assert_eq!(
    graph.evaluate_bounds().unwrap(),
    &Interval::make(Some(20), Some(30)).unwrap(),
)

pub fn get_interval(&self, index: usize) -> Interval

Returns the interval associated with the node at the given index.

Trait Implementations

impl Clone for ExprIntervalGraph

fn clone(&self) -> ExprIntervalGraph

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ExprIntervalGraph

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.