Subsystem stiffness calc set to analytic

- Subsystem.staticSolve mistakenly used the finite-difference
  coupled stiffness method. Now it uses analytic. Should be
  faster and more robust.
- In System.addBody, added DOFs parameter.

moorpy/subsystem.py

@@ -298,7 +298,7 @@ def staticSolve(self, reset=False, tol=0, profiles=0):
  self.solveEquilibrium(tol=tol)
 
  # get 2D stiffness matrices of end points
- K = self.getCoupledStiffness()
+ K = self.getCoupledStiffnessA()
 
  # transform coordinates and forces back into global frame
  if LH > 0:

moorpy/system.py

@@ -144,7 +144,8 @@ def __init__(self, file="", dirname="", rootname="", depth=0, rho=1025, g=9.81,
  rod.loadData(dirname, rootname, sep='_') 
 
 
- def addBody(self, mytype, r6, m=0, v=0, rCG=np.zeros(3), AWP=0, rM=np.zeros(3), f6Ext=np.zeros(6)):
+ def addBody(self, mytype, r6, m=0, v=0, rCG=np.zeros(3), AWP=0, 
+ rM=np.zeros(3), f6Ext=np.zeros(6), DOFs=[0,1,2,3,4,5]):
  '''Convenience function to add a Body to a mooring system
 
  Parameters
@@ -172,7 +173,8 @@ def addBody(self, mytype, r6, m=0, v=0, rCG=np.zeros(3), AWP=0, rM=np.zeros(3),
 
  '''
 
- self.bodyList.append( Body(self, len(self.bodyList)+1, mytype, r6, m=m, v=v, rCG=rCG, AWP=AWP, rM=rM, f6Ext=f6Ext) )
+ self.bodyList.append( Body(self, len(self.bodyList)+1, mytype, r6, m=m,
+ v=v, rCG=rCG, AWP=AWP, rM=rM, f6Ext=f6Ext, DOFs=DOFs) )
 
  # handle display message if/when MoorPy is reorganized by classes