From c5d223a79b7917f82f0e35487629a283ccfd1c2e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Villemot?= <sebastien@dynare.org>
Date: Tue, 22 Oct 2019 11:34:51 +0200
Subject: [PATCH] Fix semantics of ExprNode::maxLag(), maxLead() and
maxLagWithDiffsExpanded() with constants
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Those methods can return a negative value in some cases. For example,
maxLead(x₋₁) = −1.
But constants were always returning a value of zero, which means that we had
inconsistent behaviour like maxLead(x₋₁ + 2) = 0.
This commits fixes the behaviour by making these methods return the smallest
possible integer when called on constants.
---
src/ExprNode.cc | 7 ++++---
src/ExprNode.hh | 6 ++++--
2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/src/ExprNode.cc b/src/ExprNode.cc
index 8969d448..6eb9c506 100644
--- a/src/ExprNode.cc
+++ b/src/ExprNode.cc
@@ -22,6 +22,7 @@
#include <cassert>
#include <cmath>
#include <utility>
+#include <limits>
#include "ExprNode.hh"
#include "DataTree.hh"
@@ -559,19 +560,19 @@ NumConstNode::maxExoLag() const
int
NumConstNode::maxLead() const
{
- return 0;
+ return numeric_limits<int>::min();
}
int
NumConstNode::maxLag() const
{
- return 0;
+ return numeric_limits<int>::min();
}
int
NumConstNode::maxLagWithDiffsExpanded() const
{
- return 0;
+ return numeric_limits<int>::min();
}
expr_t
diff --git a/src/ExprNode.hh b/src/ExprNode.hh
index c7326d02..007459e6 100644
--- a/src/ExprNode.hh
+++ b/src/ExprNode.hh
@@ -407,12 +407,14 @@ class ExprNode
//! Returns the maximum lead of endo/exo/exodet in this expression
/*! A negative value means that the expression contains only lagged
- variables. */
+ variables. A value of numeric_limits<int>::min() means that there is
+ no variable. */
virtual int maxLead() const = 0;
//! Returns the maximum lag of endo/exo/exodet in this expression
/*! A negative value means that the expression contains only leaded
- variables. */
+ variables. A value of numeric_limits<int>::min() means that there is
+ no variable. */
virtual int maxLag() const = 0;
//! Returns the maximum lag of endo/exo/exodet, as if diffs were expanded
--
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