Index: /issm/trunk-jpl/src/c/classes/Loads/Friction.cpp
===================================================================
--- /issm/trunk-jpl/src/c/classes/Loads/Friction.cpp	(revision 27477)
+++ /issm/trunk-jpl/src/c/classes/Loads/Friction.cpp	(revision 27478)
@@ -300,7 +300,7 @@
 void Friction::GetAlphaRegCoulombComplement(IssmDouble* palpha_complement, Gauss* gauss){/*{{{*/
 
-	/* Compute the complement of Schoof's law for inversion
+	/* Compute the complement of regularised Coulombs law for inversion
 	 * d alpha2                       
-	 * -------- = |u_b|^(1/m-1) * (|u_b + u_0|)^(-1/m)
+	 * -------- = |u_b|^(1/m-1) * (|u_b|/u_0 + 1)^(-1/m)
 	 *  dC                           
 	 */
Index: /issm/trunk-jpl/src/m/classes/frictionregcoulomb.m
===================================================================
--- /issm/trunk-jpl/src/m/classes/frictionregcoulomb.m	(revision 27478)
+++ /issm/trunk-jpl/src/m/classes/frictionregcoulomb.m	(revision 27478)
@@ -0,0 +1,61 @@
+%FRICTIONREGCOULOMB class definition
+%
+%   Usage:
+%      frictionregcoulomb=frictionregcoulomb();
+
+classdef frictionregcoulomb
+	properties (SetAccess=public) 
+		C  = NaN;
+		u0 = 0.;
+		m  = NaN;
+	end
+	methods
+		function self = frictionregcoulomb(varargin) % {{{
+			switch nargin
+				case 0
+					self=setdefaultparameters(self);
+				case 1
+					self=structtoobj(frictionregcoulomb(),varargin{1});
+				otherwise
+					error('constructor not supported');
+			end
+		end % }}}
+		function self = extrude(self,md) % {{{
+			self.C    = project3d(md,'vector',self.C,'type','node');
+			self.m    = project3d(md,'vector',self.m,'type','element');
+		end % }}}
+		function self = setdefaultparameters(self) % {{{
+
+			self.u0 = 1000;
+
+		end % }}}
+		function md = checkconsistency(self,md,solution,analyses) % {{{
+
+			%Early return
+			if ~ismember('StressbalanceAnalysis',analyses) & ~ismember('ThermalAnalysis',analyses), return; end
+			md = checkfield(md,'fieldname','friction.C','timeseries',1,'NaN',1,'Inf',1,'>=',0.);
+			md = checkfield(md,'fieldname','friction.u0','NaN',1,'Inf',1,'>',0.,'numel',1);
+			md = checkfield(md,'fieldname','friction.m','NaN',1,'Inf',1,'>',0.,'size',[md.mesh.numberofelements,1]);
+		end % }}}
+		function disp(self) % {{{
+			%See Joughin et al. 2019 (equivalent form by Matt Trevers, poster at AGU 2022) https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL082526
+			disp('Regularized Couloub friction law (Joughin et al., 2019) parameters:');
+			disp('   Regularized Couloub friction law reads:');
+			disp('                       C^2 |u|^(1/m)         ');
+			disp('      tau_b = -  ____________________________');
+			disp('                        (|u|/u0 + 1)^(1/m)   ');
+			disp(' ');
+			fielddisplay(self,'C','friction coefficient [SI]');
+			fielddisplay(self,'m','m exponent (set to m=3 in original paper)');
+			fielddisplay(self,'u0','velocity controling plastic limit');
+		end % }}}
+		function marshall(self,prefix,md,fid) % {{{
+			yts=md.constants.yts;
+
+			WriteData(fid,prefix,'name','md.friction.law','data',14,'format','Integer');
+			WriteData(fid,prefix,'class','friction','object',self,'fieldname','C','format','DoubleMat','mattype',1,'timeserieslength',md.mesh.numberofvertices+1,'yts',md.constants.yts);
+			WriteData(fid,prefix,'class','friction','object',self,'fieldname','u0','format','Double','scale',1/yts);
+			WriteData(fid,prefix,'class','friction','object',self,'fieldname','m','format','DoubleMat','mattype',2);
+		end % }}}
+	end
+end