Index: /issm/trunk-jpl/src/c/classes/Materials/Matestar.cpp
===================================================================
--- /issm/trunk-jpl/src/c/classes/Materials/Matestar.cpp	(revision 21406)
+++ /issm/trunk-jpl/src/c/classes/Materials/Matestar.cpp	(revision 21407)
@@ -203,5 +203,8 @@
 /*}}}*/
 IssmDouble Matestar::GetN(){/*{{{*/
-	return 3.;
+
+	/*Output*/
+	IssmDouble n=3.0;
+	return n;
 }
 /*}}}*/
@@ -320,5 +323,22 @@
 /*}}}*/
 void  Matestar::GetViscosity_B(IssmDouble* pdmudB,IssmDouble eps_eff){/*{{{*/
-	_error_("not implemented yet");
+	/*output: */
+	IssmDouble dmudB;
+
+	/*Intermediary: */
+	IssmDouble E=1.,n;
+
+	n=GetN(); _assert_(n>0.);
+	if(n==1.){
+		/*Linear Viscous behavior (Newtonian fluid) dmudB=B/2E: */
+		dmudB=1./(2.*E);
+	}
+	else{
+		if(eps_eff==0.) dmudB = 0.;
+		else            dmudB = 1./(2.*pow(E*eps_eff*eps_eff,1./3.));
+	}
+
+	/*Return: */
+	*pdmudB=dmudB;
 }
 /*}}}*/