From: Chris Dams <Chris.Dams@mi.infn.it>
Date: Mon, 27 Mar 2006 19:13:21 +0000 (+0000)
Subject: Added .is_polynomial() method.
X-Git-Tag: release_1-4-0~101
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=commitdiff_plain;h=80ceed0c855ea06ff5acd9375ad2e0c5ca386373

Added .is_polynomial() method.
---

diff --git a/doc/tutorial/ginac.texi b/doc/tutorial/ginac.texi
index 23956d77..93b00e6f 100644
--- a/doc/tutorial/ginac.texi
+++ b/doc/tutorial/ginac.texi
@@ -905,7 +905,7 @@ int main()
 
 @node The Class Hierarchy, Symbols, Error handling, Basic Concepts
 @c    node-name, next, previous, up
-@section The Class Hierarchy
+@section The class hierarchy
 
 GiNaC's class hierarchy consists of several classes representing
 mathematical objects, all of which (except for @code{ex} and some
@@ -4172,7 +4172,7 @@ after @code{other}.
 
 @node Numerical Evaluation, Substituting Expressions, Information About Expressions, Methods and Functions
 @c    node-name, next, previous, up
-@section Numerical Evaluation
+@section Numerical evaluation
 @cindex @code{evalf()}
 
 GiNaC keeps algebraic expressions, numbers and constants in their exact form.
@@ -4612,7 +4612,7 @@ and not for locating @code{x+y} within @code{x+y+z}.
 
 @node Applying a Function on Subexpressions, Visitors and Tree Traversal, Pattern Matching and Advanced Substitutions, Methods and Functions
 @c    node-name, next, previous, up
-@section Applying a Function on Subexpressions
+@section Applying a function on subexpressions
 @cindex tree traversal
 @cindex @code{map()}
 
@@ -4757,7 +4757,7 @@ argument. You can not use functions like @samp{diff()}, @samp{op()},
 
 @node Visitors and Tree Traversal, Polynomial Arithmetic, Applying a Function on Subexpressions, Methods and Functions
 @c    node-name, next, previous, up
-@section Visitors and Tree Traversal
+@section Visitors and tree traversal
 @cindex tree traversal
 @cindex @code{visitor} (class)
 @cindex @code{accept()}
@@ -4981,6 +4981,22 @@ lst gather_indices(const ex & e)
 @c    node-name, next, previous, up
 @section Polynomial arithmetic
 
+@subsection Testing whether an expression is a polynomial
+@cindex @code{is_polynomial()}
+
+Testing whether an expression is a polynomial in one or more variables
+can be done with the method
+@example
+bool ex::is_polynomial(const ex & vars) const;
+@end example
+In the case of more than
+one variable, the variables are given as a list.
+
+@example
+(x*y*sin(y)).is_polynomial(x)         // Returns true.
+(x*y*sin(y)).is_polynomial(lst(x,y))  // Returns false.
+@end example
+
 @subsection Expanding and collecting
 @cindex @code{expand()}
 @cindex @code{collect()}
@@ -5987,7 +6003,7 @@ J.Vollinga, S.Weinzierl, hep-ph/0410259
 
 @node Complex Conjugation, Solving Linear Systems of Equations, Multiple polylogarithms, Methods and Functions
 @c    node-name, next, previous, up
-@section Complex Conjugation
+@section Complex conjugation
 @c
 @cindex @code{conjugate()}
 
@@ -6021,7 +6037,7 @@ change this behavior, you have to supply a specialized conjugation method for yo
 
 @node Solving Linear Systems of Equations, Input/Output, Complex Conjugation, Methods and Functions
 @c    node-name, next, previous, up
-@section Solving Linear Systems of Equations
+@section Solving linear systems of equations
 @cindex @code{lsolve()}
 
 The function @code{lsolve()} provides a convenient wrapper around some
diff --git a/ginac/basic.cpp b/ginac/basic.cpp
index f65e3f0c..a3c727be 100644
--- a/ginac/basic.cpp
+++ b/ginac/basic.cpp
@@ -325,6 +325,12 @@ ex basic::map(map_function & f) const
 		return *this;
 }
 
+/** Check whether this is a polynomial in the given variables. */
+bool basic::is_polynomial(const ex & var) const
+{
+	return !has(var) || is_equal(ex_to<basic>(var));
+}
+
 /** Return degree of highest power in object s. */
 int basic::degree(const ex & s) const
 {
diff --git a/ginac/basic.h b/ginac/basic.h
index fc825226..6b117cc9 100644
--- a/ginac/basic.h
+++ b/ginac/basic.h
@@ -180,6 +180,7 @@ public:
 	}
 
 	// degree/coeff
+	virtual bool is_polynomial(const ex & var) const;
 	virtual int degree(const ex & s) const;
 	virtual int ldegree(const ex & s) const;
 	virtual ex coeff(const ex & s, int n = 1) const;
diff --git a/ginac/constant.cpp b/ginac/constant.cpp
index 86fb55b7..5cfecc96 100644
--- a/ginac/constant.cpp
+++ b/ginac/constant.cpp
@@ -146,6 +146,11 @@ ex constant::evalf(int level) const
 	return *this;
 }
 
+bool constant::is_polynomial(const ex & var) const
+{
+	return true;
+}
+
 // protected
 
 /** Implementation of ex::diff() for a constant always returns 0.
diff --git a/ginac/constant.h b/ginac/constant.h
index 331ad209..99226376 100644
--- a/ginac/constant.h
+++ b/ginac/constant.h
@@ -49,6 +49,7 @@ public:
 	// functions overriding virtual functions from base classes
 public:
 	ex evalf(int level = 0) const;
+	bool is_polynomial(const ex & var) const;
 protected:
 	ex derivative(const symbol & s) const;
 	bool is_equal_same_type(const basic & other) const;
diff --git a/ginac/ex.cpp b/ginac/ex.cpp
index a5ede054..f1835377 100644
--- a/ginac/ex.cpp
+++ b/ginac/ex.cpp
@@ -240,6 +240,20 @@ ex ex::rhs() const
 	return bp->op(1);
 }
 
+/** Check whether expression is a polynomial. */
+bool ex::is_polynomial(const ex & vars) const
+{
+	if (is_a<lst>(vars)) {
+		const lst & varlst = ex_to<lst>(vars);
+		for (lst::const_iterator i=varlst.begin(); i!=varlst.end(); ++i)
+			if (!bp->is_polynomial(*i))
+				return false;
+		return true;
+	}
+	else
+		return bp->is_polynomial(vars);
+}
+
 // private
 
 /** Make this ex writable (if more than one ex handle the same basic) by 
diff --git a/ginac/ex.h b/ginac/ex.h
index 697f3b4e..c23336ba 100644
--- a/ginac/ex.h
+++ b/ginac/ex.h
@@ -159,6 +159,7 @@ public:
 	void traverse(visitor & v) const { traverse_preorder(v); }
 
 	// degree/coeff
+	bool is_polynomial(const ex & vars) const;
 	int degree(const ex & s) const { return bp->degree(s); }
 	int ldegree(const ex & s) const { return bp->ldegree(s); }
 	ex coeff(const ex & s, int n = 1) const { return bp->coeff(s, n); }
@@ -690,6 +691,9 @@ inline bool has(const ex & thisex, const ex & pattern, unsigned options = 0)
 inline bool find(const ex & thisex, const ex & pattern, lst & found)
 { return thisex.find(pattern, found); }
 
+inline bool is_polynomial(const ex & thisex, const ex & vars)
+{ return thisex.is_polynomial(vars); }
+
 inline int degree(const ex & thisex, const ex & s)
 { return thisex.degree(s); }
 
diff --git a/ginac/expairseq.cpp b/ginac/expairseq.cpp
index 458b440d..5652d89c 100644
--- a/ginac/expairseq.cpp
+++ b/ginac/expairseq.cpp
@@ -27,6 +27,7 @@
 
 #include "expairseq.h"
 #include "lst.h"
+#include "add.h"
 #include "mul.h"
 #include "power.h"
 #include "relational.h"
@@ -347,6 +348,17 @@ ex expairseq::conjugate() const
 	return result;
 }
 
+bool expairseq::is_polynomial(const ex & var) const
+{
+	if (!is_exactly_a<add>(*this) && !is_exactly_a<mul>(*this))
+		return basic::is_polynomial(var);
+	for (epvector::const_iterator i=seq.begin(); i!=seq.end(); ++i) {
+		if (!(i->rest).is_polynomial(var))
+			return false;
+	}
+	return true;
+}
+
 bool expairseq::match(const ex & pattern, lst & repl_lst) const
 {
 	// This differs from basic::match() because we want "a+b+c+d" to
diff --git a/ginac/expairseq.h b/ginac/expairseq.h
index acc2ce1e..4cfc0579 100644
--- a/ginac/expairseq.h
+++ b/ginac/expairseq.h
@@ -86,6 +86,7 @@ public:
 	bool match(const ex & pattern, lst & repl_lst) const;
 	ex subs(const exmap & m, unsigned options = 0) const;
 	ex conjugate() const;
+	bool is_polynomial(const ex & var) const;
 protected:
 	bool is_equal_same_type(const basic & other) const;
 	unsigned return_type() const;
diff --git a/ginac/numeric.cpp b/ginac/numeric.cpp
index b8170e71..278741f1 100644
--- a/ginac/numeric.cpp
+++ b/ginac/numeric.cpp
@@ -603,6 +603,11 @@ bool numeric::info(unsigned inf) const
 	return false;
 }
 
+bool numeric::is_polynomial(const ex & var) const
+{
+	return true;
+}
+
 int numeric::degree(const ex & s) const
 {
 	return 0;
diff --git a/ginac/numeric.h b/ginac/numeric.h
index f0e3362f..ff460638 100644
--- a/ginac/numeric.h
+++ b/ginac/numeric.h
@@ -105,6 +105,7 @@ public:
 public:
 	unsigned precedence() const {return 30;}
 	bool info(unsigned inf) const;
+	bool is_polynomial(const ex & var) const;
 	int degree(const ex & s) const;
 	int ldegree(const ex & s) const;
 	ex coeff(const ex & s, int n = 1) const;
diff --git a/ginac/power.cpp b/ginac/power.cpp
index 6f6f178d..95a01ace 100644
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -258,6 +258,15 @@ ex power::map(map_function & f) const
 		return *this;
 }
 
+bool power::is_polynomial(const ex & var) const
+{
+	if (exponent.has(var))
+		return false;
+	if (!exponent.info(info_flags::nonnegint))
+		return false;
+	return basis.is_polynomial(var);
+}
+
 int power::degree(const ex & s) const
 {
 	if (is_equal(ex_to<basic>(s)))
diff --git a/ginac/power.h b/ginac/power.h
index 48ca5b5d..c7645247 100644
--- a/ginac/power.h
+++ b/ginac/power.h
@@ -54,6 +54,7 @@ public:
 	size_t nops() const;
 	ex op(size_t i) const;
 	ex map(map_function & f) const;
+	bool is_polynomial(const ex & var) const;
 	int degree(const ex & s) const;
 	int ldegree(const ex & s) const;
 	ex coeff(const ex & s, int n = 1) const;
diff --git a/ginac/symbol.cpp b/ginac/symbol.cpp
index 6b37ee12..10b38a8e 100644
--- a/ginac/symbol.cpp
+++ b/ginac/symbol.cpp
@@ -226,6 +226,11 @@ ex symbol::conjugate() const
 	}
 }
 
+bool symbol::is_polynomial(const ex & var) const
+{
+	return true;
+}
+
 // protected
 
 /** Implementation of ex::diff() for single differentiation of a symbol.
diff --git a/ginac/symbol.h b/ginac/symbol.h
index 3b187d61..b7c17a80 100644
--- a/ginac/symbol.h
+++ b/ginac/symbol.h
@@ -75,6 +75,7 @@ public:
 	unsigned return_type() const { return ret_type; }
 	tinfo_t return_type_tinfo() const { return ret_type_tinfo; }
 	ex conjugate() const;
+	bool is_polynomial(const ex & var) const;
 protected:
 	ex derivative(const symbol & s) const;
 	bool is_equal_same_type(const basic & other) const;