ADDED   mttroot/mtt/lib/cr/r/defaultcr.r
Index: mttroot/mtt/lib/cr/r/defaultcr.r
==================================================================
--- /dev/null
+++ mttroot/mtt/lib/cr/r/defaultcr.r
@@ -0,0 +1,63 @@
+% 
+%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
+%     %%%%% Model Transformation Tools %%%%%
+%     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Linear constitutive relationship.
+
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% Version control history
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% %% $Id$
+% %% $Log$
+% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+%Linear Constitutive Relationship for single port components: R,C,I.
+% e = Gain*f (if gain_causality = flow) 
+%           f = Gain*e (if gain_causality = effort)
+OPERATOR lin;
+FOR ALL gain_causality, gain, causality, input, other_causality
+SUCH THAT causality = gain_causality
+LET lin(gain_causality, gain, other_causality, 1, input, causality, 1)
+	 = gain*input;
+
+%Linear CR: e = (1/Gain)*f (if gain_causality = flow) 
+%           f = (1/Gain)*e (if gain_causality = effort)
+FOR ALL gain_causality, gain, causality, input, other_causality
+SUCH THAT causality NEQ gain_causality
+LET lin(gain_causality, gain, other_causality, 1, input, causality, 1)
+	 = input/gain;
+
+
+% Linear Constitutive Relationship for AE and AF
+% Output = gain * input
+
+% Unicausal form
+FOR ALL gain, input, causality
+LET lin(gain, causality, 2, input, causality, 1) = gain*input;
+
+%Bicausal form
+FOR ALL gain, output, causality
+LET lin(gain, causality, 1, output, causality, 2) = output/gain;
+
+% Linear Constitutive Relationship for TF
+FOR ALL gain, input, causality, gain_causality, outport, inport
+SUCH THAT (
+	(causality = gain_causality) AND (outport = 2)
+	OR
+	(causality NEQ gain_causality) AND (outport = 1)
+	)
+LET lin(gain_causality, gain, causality, outport, input, causality, inport)
+	 = gain*input;
+
+FOR ALL gain, input, causality, gain_causality, outport, inport
+SUCH THAT (
+	(causality NEQ gain_causality) AND (outport = 2)
+	OR
+	(causality = gain_causality) AND (outport = 1)
+	)
+LET lin(gain_causality, gain, causality, outport, input, causality, inport)
+	 = input/gain;
+
+END;
+