From: Jens Vollinga <jensv@nikhef.nl>
Date: Mon, 8 Sep 2008 17:17:56 +0000 (+0200)
Subject: Fixed bug in unvariate factorization. Bound for lifting was using a ordinary
X-Git-Tag: release_1-5-0~66
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?a=commitdiff_plain;h=bb6b3d82cdf9e7ff4ecac89c47e63024e39ec96b;p=ginac.git

Fixed bug in unvariate factorization. Bound for lifting was using a ordinary
int instead of a cl_I.
---

diff --git a/check/exam_factor.cpp b/check/exam_factor.cpp
index 7e156487..fa895c6d 100644
--- a/check/exam_factor.cpp
+++ b/check/exam_factor.cpp
@@ -94,6 +94,13 @@ static unsigned exam_factor1()
 	e = x;
 	result += check_factor(e);
 
+	// x^37 + 1
+	e = ex("(1+x)*(1+x^2-x^29-x^11-x^25-x^9-x^35+x^20-x^3+x^16-x^15-x-x^13+x^28+x^24-x^33+x^8-x^19+x^36+x^12-x^27+x^10-x^23+x^18+x^14+x^34-x^31+x^32+x^30-x^5+x^26+x^4+x^22-x^21-x^7-x^17+x^6)", syms);
+	result += check_factor(e);
+
+	e = ex("(1+4*x)*x^2*(1-4*x+16*x^2)*(3+5*x+92*x^3)", syms);
+	result += check_factor(e);
+
 	return result;
 }
 
diff --git a/ginac/factor.cpp b/ginac/factor.cpp
index 3afaec54..886819a3 100644
--- a/ginac/factor.cpp
+++ b/ginac/factor.cpp
@@ -1048,8 +1048,8 @@ static ex hensel_univar(const ex& a_, const ex& x, unsigned int p, const UniPoly
 		maxcoeff += pow(abs(a.coeff(x, i)),2);
 	}
 	cl_I normmc = ceiling1(the<cl_R>(cln::sqrt(ex_to<numeric>(maxcoeff).to_cl_N())));
-	unsigned int maxdegree = (u1_.degree() > w1_.degree()) ? u1_.degree() : w1_.degree();
-	unsigned int B = cl_I_to_uint(normmc * expt_pos(cl_I(2), maxdegree));
+	cl_I maxdegree = (u1_.degree() > w1_.degree()) ? u1_.degree() : w1_.degree();
+	cl_I B = normmc * expt_pos(cl_I(2), maxdegree);
 
 	// step 1
 	ex alpha = a.lcoeff(x);
@@ -1077,10 +1077,11 @@ static ex hensel_univar(const ex& a_, const ex& x, unsigned int p, const UniPoly
 	ex u = replace_lc(u1.to_ex(x), x, gamma);
 	ex w = replace_lc(w1.to_ex(x), x, alpha);
 	ex e = expand(a - u * w);
-	unsigned int modulus = p;
+	numeric modulus = p;
+	const numeric maxmodulus(2*B*gamma_ui);
 
 	// step 4
-	while ( !e.is_zero() && modulus < 2*B*gamma_ui ) {
+	while ( !e.is_zero() && modulus < maxmodulus ) {
 		ex c = e / modulus;
 		phi = expand(s.to_ex(x)*c);
 		UniPoly sigmatilde(R, phi, x);