Improved handling of symbolic variables in kinematics and N_link_chain code

Author: Ross Hatton

ProgramFiles/Geometry/NLinkChain/N_link_chain.m

@@ -151,7 +151,7 @@
 % the array symbolic, because matlab tries to cast items being inserted
 % into an array into the array class, rather than converting the array to
 % accomodate the class of the items being inserted 
-if isa(jointangles,'sym')
+if or( isa(jointangles,'sym'), isa(linklengths,'sym') )
     chain_m = sym(chain_m);
 end
 
@@ -185,7 +185,7 @@
 % the array symbolic, because matlab tries to cast items being inserted
 % into an array into the array class, rather than converting the array to
 % accomodate the class of the items being inserted 
-if isa(jointangles,'sym')
+if or( isa(jointangles,'sym'), isa(linklengths,'sym') )
     jointchain_m = sym(jointchain_m);
 end
 
@@ -225,7 +225,7 @@
 % the array symbolic, because matlab tries to cast items being inserted
 % into an array into the array class, rather than converting the array to
 % accomodate the class of the items being inserted 
-if isa(jointangles,'sym')
+if or( isa(jointangles,'sym'),isa(linklengths,'sym') )
     J_pattern = sym(J_pattern);
 end
 

ProgramFiles/Physics/Nonholonomic/Nonholonomic_connection_discrete.m

@@ -97,9 +97,17 @@
 
     % Prevent Matlab from playing tricks with imaginary numbers on symbolic
     % inputs and from complaining about assumptions on constants
-    if isa(jointangles,'sym')
+    if or( isa(jointangles,'sym'), isa(geometry.linklengths,'sym') )
         omega = sym(omega);
-        assume(symvar(jointangles),'real')
+        symjointangles = symvar(jointangles);
+        if ~isempty(symjointangles)
+            assume(symjointangles,'real')
+        end
+        symlinklengths = symvar(geometry.linklengths);
+        if ~isempty(symlinklengths)
+            assume(symlinklengths,'real')
+        end
+
         warning('off','symbolic:sym:sym:AssumptionsOnConstantsIgnored')
     end
 

ProgramFiles/Utilities/kinematics/Adjinv.m

@@ -8,4 +8,8 @@
 
 Adjoint_inverse_action = TgLginv(g)*TeRg(g);
 
+if isa(Adjoint_inverse_action,'sym')
+    Adjoint_inverse_action = simplify(Adjoint_inverse_action,'steps',50);
+end
+
 end