Halide 22.0.0 Halide compiler and libraries

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Solve.h
Go to the documentation of this file.
1#ifndef SOLVE_H
2#define SOLVE_H
3
4/** Defines methods for manipulating and analyzing boolean expressions. */
5
6#include "Bounds.h"
7#include "Expr.h"
8#include "Interval.h"
9#include "Scope.h"
10
11 namespace Halide {
12 namespace Internal {
13
14 struct SolverResult {
15 Expr result;
16 bool fully_solved;
17};
18
19/** Attempts to collect all instances of a variable in an expression
20 * tree and place it as far to the left as possible, and as far up the
21 * tree as possible (i.e. outside most parentheses). If the expression
22 * is an equality or comparison, this 'solves' the equation. Returns a
23 * pair of Expr and bool. The Expr is the mutated expression, and the
24 * bool indicates whether there is a single instance of the variable
25 * in the result. If it is false, the expression has only been partially
26 * solved, and there are still multiple instances of the variable. */
27 SolverResult solve_expression(
28 const Expr &e, const std::string &variable,
29 const Scope<Expr> &scope = Scope<Expr>::empty_scope());
30
31/** Find the smallest interval such that the condition is either true
32 * or false inside of it, but definitely false outside of it. Never
33 * returns undefined Exprs, instead it uses variables called "pos_inf"
34 * and "neg_inf" to represent positive and negative infinity. */
35 Interval solve_for_outer_interval(const Expr &c, const std::string &variable);
36
37/** Find the largest interval such that the condition is definitely
38 * true inside of it, and might be true or false outside of it. */
39 Interval solve_for_inner_interval(const Expr &c, const std::string &variable);
40
41/** Take a conditional that includes variables that vary over some
42 * domain, and convert it to a more conservative (less frequently
43 * true) condition that doesn't depend on those variables. Formally,
44 * the output expr implies the input expr.
45 *
46 * The condition may be a vector condition, in which case we also
47 * 'and' over the vector lanes, and return a scalar result. */
48 Expr and_condition_over_domain(const Expr &c, const Scope<Interval> &varying);
49
50/** Take a conditional that includes variables that vary over some
51 * domain, and convert it to a weaker (less frequently false) condition
52 * that doesn't depend on those variables. Formally, the input expr
53 * implies the output expr. Note that this function might be unable to
54 * provide a better response than simply const_true(). */
55 Expr or_condition_over_domain(const Expr &c, const Scope<Interval> &varying);
56
57 void solve_test();
58
59} // namespace Internal
60} // namespace Halide
61
62#endif
Bounds.h
Methods for computing the upper and lower bounds of an expression, and the regions of a function read...
Expr.h
Base classes for Halide expressions (Halide::Expr) and statements (Halide::Internal::Stmt)
Interval.h
Defines the Interval class.
Scope.h
Defines the Scope class, which is used for keeping track of names in a scope while traversing IR.
Halide::Internal::Scope
A common pattern when traversing Halide IR is that you need to keep track of stuff when you find a Le...
Definition Scope.h:94
Halide::Internal::solve_for_outer_interval
Interval solve_for_outer_interval(const Expr &c, const std::string &variable)
Find the smallest interval such that the condition is either true or false inside of it,...
Halide::Internal::and_condition_over_domain
Expr and_condition_over_domain(const Expr &c, const Scope< Interval > &varying)
Take a conditional that includes variables that vary over some domain, and convert it to a more conse...
Halide::Internal::solve_expression
SolverResult solve_expression(const Expr &e, const std::string &variable, const Scope< Expr > &scope=Scope< Expr >::empty_scope())
Attempts to collect all instances of a variable in an expression tree and place it as far to the left...
Halide::Internal::solve_for_inner_interval
Interval solve_for_inner_interval(const Expr &c, const std::string &variable)
Find the largest interval such that the condition is definitely true inside of it,...
Halide::Internal::solve_test
void solve_test()
Halide::Internal::or_condition_over_domain
Expr or_condition_over_domain(const Expr &c, const Scope< Interval > &varying)
Take a conditional that includes variables that vary over some domain, and convert it to a weaker (le...
Halide
This file defines the class FunctionDAG, which is our representation of a Halide pipeline,...
Definition AbstractGenerator.h:19
Halide::LinkageType::Internal
@ Internal
Not visible externally, similar to 'static' linkage in C.
Halide::cast
Internal::ConstantInterval cast(Type t, const Internal::ConstantInterval &a)
Cast operators for ConstantIntervals.
Halide::Expr
A fragment of Halide syntax.
Definition Expr.h:258
Halide::Internal::Interval
A class to represent ranges of Exprs.
Definition Interval.h:14
Halide::Internal::SolverResult
Definition Solve.h:14
Halide::Internal::SolverResult::fully_solved
bool fully_solved
Definition Solve.h:16
Halide::Internal::SolverResult::result
Expr result
Definition Solve.h:15