From aec46b608e6b7d67a4b96d52c58d2c3fce8486fb Mon Sep 17 00:00:00 2001
From: EvilSpirit <anandamide@mail.ru>
Date: Thu, 24 Jun 2021 11:29:24 -0500
Subject: [PATCH] Add a method to Expr.

(Split out from earlier "Eigen library integration" commit)
---
 src/expr.cpp | 5 +++++
 src/expr.h   | 1 +
 2 files changed, 6 insertions(+)

diff --git a/src/expr.cpp b/src/expr.cpp
index 6030cb1..b612dd2 100644
--- a/src/expr.cpp
+++ b/src/expr.cpp
@@ -430,6 +430,11 @@ bool Expr::DependsOn(hParam p) const {
 bool Expr::Tol(double a, double b) {
     return fabs(a - b) < 0.001;
 }
+
+bool Expr::IsZeroConst() const {
+    return op == Op::CONSTANT && EXACT(v == 0.0);
+}
+
 Expr *Expr::FoldConstants() {
     Expr *n = AllocExpr();
     *n = *this;
diff --git a/src/expr.h b/src/expr.h
index efd44a5..d59930b 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -73,6 +73,7 @@ public:
     void ParamsUsedList(List<hParam> *list) const;
     bool DependsOn(hParam p) const;
     static bool Tol(double a, double b);
+    bool IsZeroConst() const;
     Expr *FoldConstants();
     void Substitute(hParam oldh, hParam newh);