Index: /issm/trunk-jpl/src/c/classes/Loads/Friction.cpp
===================================================================
--- /issm/trunk-jpl/src/c/classes/Loads/Friction.cpp	(revision 27672)
+++ /issm/trunk-jpl/src/c/classes/Loads/Friction.cpp	(revision 27673)
@@ -141,4 +141,7 @@
 				GetAlphaSchoofComplement(palpha_complement,gauss);
 				break;
+			case 13:
+				GetAlphaCoulomb2Complement(palpha_complement,gauss);
+				break;
 			case 14:
 				GetAlphaRegCoulombComplement(palpha_complement,gauss);
@@ -354,4 +357,35 @@
 	/*Assign output pointers:*/
 	*palpha_complement=alpha_complement;
+}/*}}}*/
+void Friction::GetAlphaCoulomb2Complement(IssmDouble* palpha_complement, Gauss* gauss){/*{{{*/
+
+	/* Compute the complement of Cornford's friction law for inversion
+	 * d alpha2                       
+	 * ------ = (C*N*v^m)/(C^(2/m)*v + (N/2)^(1/m))^m - (C^(2/m - 1)*C^2*N*v*v^m)/(C^(2/m)*v + (N/2)^(1/m))^(m + 1)
+	 *  dC                           
+	 */
+
+	/*diverse: */
+	IssmDouble  m, C;
+	IssmDouble  alpha_complement;
+
+	/*Recover parameters: */
+	element->GetInputValue(&C,gauss,FrictionCEnum);
+	element->GetInputValue(&m,gauss,FrictionMEnum);
+
+	/*Get effective pressure and velocity magnitude*/
+	IssmDouble N = EffectivePressure(gauss);
+	IssmDouble v = VelMag(gauss);
+
+	/*Compute alpha*/
+	if(v<1e-10){
+		alpha_complement = 0.;
+	}
+	else{
+		alpha_complement= pow(0.5*N,1./m+1)* pow(v,m-1.) * pow(v*pow(C,1./m) +pow(0.5*N,1./m) ,-m-1.);
+	}
+
+	/*Assign output pointers:*/
+	*palpha_complement=alpha_complement/2.;
 }/*}}}*/
 void Friction::GetAlpha2(IssmDouble* palpha2, Gauss* gauss){/*{{{*/
Index: /issm/trunk-jpl/src/c/classes/Loads/Friction.h
===================================================================
--- /issm/trunk-jpl/src/c/classes/Loads/Friction.h	(revision 27672)
+++ /issm/trunk-jpl/src/c/classes/Loads/Friction.h	(revision 27673)
@@ -41,4 +41,5 @@
 		void  GetAlphaViscousComplement(IssmDouble* alpha_complement,Gauss* gauss);
 		void  GetAlphaSchoofComplement(IssmDouble* alpha_complement,Gauss* gauss);
+		void  GetAlphaCoulomb2Complement(IssmDouble* alpha_complement,Gauss* gauss);
 		void  GetAlphaRegCoulombComplement(IssmDouble* alpha_complement,Gauss* gauss);
 		void  GetAlphaWeertmanComplement(IssmDouble* alpha_complement,Gauss* gauss);