From: Christian Bauer <Christian.Bauer@uni-mainz.de>
Date: Wed, 25 Oct 2000 18:33:32 +0000 (+0000)
Subject: - non-integer powers are treated as 0 by (l)degree() and coeff()
X-Git-Tag: release_0-7-0~21
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=commitdiff_plain;h=8397b7a8f4d9a8e6db0025813f125ee365b15e6a

- non-integer powers are treated as 0 by (l)degree() and coeff()
---

diff --git a/NEWS b/NEWS
index 4a119ee6..228d5a44 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,11 @@
 This file records noteworthy changes.
 
+0.6.5 ()
+* Non-integer powers of a symbol are treated as constants by (l)degree() and
+  coeff(). Using these functions on an expression containing such powers used
+  to fail with an internal error message. The side-effect is that collect()
+  can be used on expressions which are not polynomials.
+
 0.6.4 (10 August 2000)
 * Complete revamp of methods in class matrix.  Some redundant (and poor)
   implementations of elimination schemes were thrown out.  The code is now
diff --git a/ginac/mul.cpp b/ginac/mul.cpp
index ee00dd4e..ad7aa13e 100644
--- a/ginac/mul.cpp
+++ b/ginac/mul.cpp
@@ -310,7 +310,8 @@ int mul::degree(const symbol & s) const
 {
 	int deg_sum = 0;
 	for (epvector::const_iterator cit=seq.begin(); cit!=seq.end(); ++cit) {
-		deg_sum+=(*cit).rest.degree(s) * ex_to_numeric((*cit).coeff).to_int();
+		if (ex_to_numeric(cit->coeff).is_integer())
+			deg_sum+=cit->rest.degree(s) * ex_to_numeric(cit->coeff).to_int();
 	}
 	return deg_sum;
 }
@@ -319,7 +320,8 @@ int mul::ldegree(const symbol & s) const
 {
 	int deg_sum = 0;
 	for (epvector::const_iterator cit=seq.begin(); cit!=seq.end(); ++cit) {
-		deg_sum+=(*cit).rest.ldegree(s) * ex_to_numeric((*cit).coeff).to_int();
+		if (ex_to_numeric(cit->coeff).is_integer())
+			deg_sum+=cit->rest.ldegree(s) * ex_to_numeric(cit->coeff).to_int();
 	}
 	return deg_sum;
 }
diff --git a/ginac/power.cpp b/ginac/power.cpp
index 53342a9e..a0c6ea44 100644
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -282,9 +282,12 @@ ex & power::let_op(int i)
 int power::degree(const symbol & s) const
 {
 	if (is_exactly_of_type(*exponent.bp,numeric)) {
-		if ((*basis.bp).compare(s)==0)
-			return ex_to_numeric(exponent).to_int();
-		else
+		if ((*basis.bp).compare(s)==0) {
+			if (ex_to_numeric(exponent).is_integer())
+				return ex_to_numeric(exponent).to_int();
+			else
+				return 0;
+		} else
 			return basis.degree(s) * ex_to_numeric(exponent).to_int();
 	}
 	return 0;
@@ -293,9 +296,12 @@ int power::degree(const symbol & s) const
 int power::ldegree(const symbol & s) const 
 {
 	if (is_exactly_of_type(*exponent.bp,numeric)) {
-		if ((*basis.bp).compare(s)==0)
-			return ex_to_numeric(exponent).to_int();
-		else
+		if ((*basis.bp).compare(s)==0) {
+			if (ex_to_numeric(exponent).is_integer())
+				return ex_to_numeric(exponent).to_int();
+			else
+				return 0;
+		} else
 			return basis.ldegree(s) * ex_to_numeric(exponent).to_int();
 	}
 	return 0;
@@ -305,17 +311,27 @@ ex power::coeff(const symbol & s, int n) const
 {
 	if ((*basis.bp).compare(s)!=0) {
 		// basis not equal to s
-		if (n==0) {
+		if (n == 0)
 			return *this;
-		} else {
+		else
 			return _ex0();
+	} else {
+		// basis equal to s
+		if (is_exactly_of_type(*exponent.bp, numeric) && ex_to_numeric(exponent).is_integer()) {
+			// integer exponent
+			int int_exp = ex_to_numeric(exponent).to_int();
+			if (n == int_exp)
+				return _ex1();
+			else
+				return _ex0();
+		} else {
+			// non-integer exponents are treated as zero
+			if (n == 0)
+				return *this;
+			else
+				return _ex0();
 		}
-	} else if (is_exactly_of_type(*exponent.bp,numeric)&&
-			   (static_cast<const numeric &>(*exponent.bp).compare(numeric(n))==0)) {
-		return _ex1();
 	}
-
-	return _ex0();
 }
 
 ex power::eval(int level) const