Subsystem updates for "span" consistency, "heading", plus a couple te…

…sts updates:

- In Subsystem, "span" is now used consistently to be the horizontal
  distance from end A to end B.
- rAFair and rBFair are gone, replaced with rad_fair, z_fair , and span.
- Subsystem.Heading is now compass heading in degrees.
- Added a couple missing tests files, hopefully automated tests now pass.

moorpy/subsystem.py

@@ -90,10 +90,13 @@ def __init__(self, mooringSys=None, num=0, depth=0, rho=1025, g=9.81,
             self.current = getFromDict(kwargs, 'current', shape=3)
 
         self.shared     = getFromDict(kwargs, 'shared', dtype=bool, default=False)  # flag to indicate shared line
-        self.span    = getFromDict(kwargs, 'span', default=0)                 # spacing (to rename as span<<<)
-        self.rBFair = getFromDict(kwargs, 'rBFair', shape=-1, default=[0,0,0])  # [m] end coordinates relative to attached body's ref point
-        self.rAFair = getFromDict(kwargs, 'rAFair', shape=-1, default=[0,0,0])  # [m] counterpart to rBFair for shared lines
-
+        self.span   = getFromDict(kwargs, 'span', default=0)  # horizontal end-end distance [m]
+        self.rad_fair = getFromDict(kwargs, 'rad_fair', default=0)  # [m] fairlead radius [m]
+        self.z_fair   = getFromDict(kwargs, 'z_fair'  , default=0)  # [m] fairlead z coord [m]
+
+        # the old rAFair input for the position of a second fairlead of a shaerd mooring line is gone
+        # currently we assume rad_fair and z_fair are same for both ends of a shared line...
+
         # seabed bathymetry - seabedMod 0 = flat; 1 = uniform slope, 2 = grid
         self.seabedMod = 0
 
@@ -188,12 +191,12 @@ def makeGeneric(self, lengths, types, connectors=[], suspended=0):
 
         # set end A location depending on whether configuration is suspended/symmetrical
         if suspended==2:  # symmetrical suspended case
-            rA = np.array([-0.5*self.span, 0, -1])  # shared line midpiont coordinates
+            rA = np.array([-0.5*self.span-self.rad_fair, 0, -1])  # shared line midpoint coordinates
         elif suspended==1:  # general suspended case
-            rA = np.array([-self.span + self.rAFair[0], 0, self.rAFair[2]])  # other suspended end
-        else:
-            rA = np.array([-self.span, 0, -self.depth])    # anchor coordinates
-        rB = np.array([-self.rBFair[0], 0, self.rBFair[2]])     # fairlead coordinates
+            rA = np.array([-self.span-self.self.ss + self.rad_fair, 0, self.z_fair])  # other suspended end
+        else:  # normal anchored line case
+            rA = np.array([-self.span-self.rad_fair, 0, -self.depth])  # anchor coordinates
+        rB = np.array([-self.rad_fair, 0, self.z_fair])     # fairlead coordinates
 
         self.rA = rA
         self.rB = rB
@@ -436,15 +439,15 @@ def setOffset(self, offset, z=0):
         '''Moves end B of the Subsystem to represent an offset from the 
         undisplaced position of the endpoint. End A is set based on the 
         'span' (shouldn't change), and B is set based on offset and the
-        rBFair setting. Optional argument z can be added for a z offset.
+        rad_fair/z_fair setting. Optional argument z can be added for a z offset.
         '''
 
         # Use static EA values and unstretched lengths
         self.revertToStaticStiffness()
 
         # Ensure end A position and set end B position to offset values
-        self.rA = np.array([-self.span, 0, self.rA[2]])
-        self.rB = np.array([-self.rBFair[0] + offset, 0, self.rBFair[2]+z]) 
+        self.rA = np.array([-self.span-self.rad_fair, 0, self.rA[2]])
+        self.rB = np.array([-self.rad_fair + offset, 0, self.z_fair+z]) 
 
         self.staticSolve(tol=self.eqtol)  # solve the subsystem
 
@@ -465,14 +468,14 @@ def setDynamicOffset(self, offset, z=0):
         applies dynamic amplification factors (DAFs) on the difference from
         the mean tensions (which would have been calculated in getOffset).
         End A is set based on the 'span' (shouldn't change), 
-        and B is set based on offset and the rBFair setting. 
+        and B is set based on offset and the rad_fair/z_fair setting. 
         Optional argument z can be added for a z offset.
         '''
 
         self.activateDynamicStiffness()  # use dynamic EA values
 
         # adjust end B to the absolute offsets specified
-        self.rB = np.array([-self.rBFair[0] + offset, 0, self.rBFair[2]+z]) 
+        self.rB = np.array([-self.rad_fair + offset, 0, self.z_fair+z]) 
 
         self.staticSolve(tol=self.eqtol)  # solve the subsystem
 
@@ -605,7 +608,7 @@ def getYawStiffness(self):
 
         tau0 = -self.fB[0]  # horizontal tension component [N]
 
-        yaw_stiff = (tau0/l)*self.rBFair[0]**2 + tau0*self.rBFair[0]  # [N-m]
+        yaw_stiff = (tau0/l)*self.rad_fair**2 + tau0*self.rad_fair  # [N-m]
 
         return yaw_stiff
 

tests/case7.dat

@@ -0,0 +1,48 @@
+MoorDyn Input File
+Case 7: Single catenary line attached to body to test 6DOF stifness - case b: 3Doffset
+----------------------- LINE TYPES ------------------------------------------        
+Name  Diam  MassDen  EA       BA/-zeta   EI    Cd    Ca   CdAx   CaAx 
+(-)   (m)   (kg/m)   (N)      (N-s/-)   (-)   (-)   (-)   (-)   (-)     
+main   0.2   200.00  2.0E+09      -1        0     4    0.27  4      0.20   
+----------------------- BODIES ------------------------------------------------------
+ID   Attachment    X0     Y0     Z0     r0      p0     y0     Mass   CG*     I*      Volume   CdA*   Ca*
+(#)     (-)        (m)    (m)    (m)   (deg)   (deg)  (deg)   (kg)   (m)   (kg-m^2)  (m^3)   (m^2)  (-)
+1     coupled      0.00   0.00   0.00   0.00   0.00   0.00     0.0    0.0   0.000e+00   0.0   0.00  0.00   
+---------------------- POINTS --------------------------------                                       
+Node Type      X     Y      Z     M    V     CdA   CA
+(-)  (-)      (m)   (m)    (m)   (kg) (m^3) (m^2) (-)
+1   Fixed    100.0  0.0   -50.0    0    0     0    0
+2   Body1      5.0   3.0   -10.0    0    0     0    0
+---------------------- LINES --------------------------------------       
+Line  LineType EndA     EndB    UnstrLen  NumSegs    Flags/Outputs                   
+(-)   (-)      (-)       (-)      (m)       (-)        (-)                 
+1     main      1         2       107.00    80         pt                  
+---------------------- SOLVER OPTIONS ---------------------------------------    
+50      WtrDpth                                       
+0.0002    dtM       - time step to use in mooring integration (s)
+3.0e6    kbot      - bottom stiffness (Pa/m)
+3.0e5    cbot      - bottom damping (Pa-s/m)
+1.0      dtIC      - time interval for analyzing convergence during IC gen (s)
+60.0     TmaxIC    - max time for ic gen (s)
+4.0      CdScaleIC - factor by which to scale drag coefficients during dynamic relaxation (-)
+0.001    threshIC  - threshold for IC convergence (-)                                          
+------------------------ OUTPUTS --------------------------------------------                                           
+FairTen1                                         
+AnchTen1   
+Con1fx    
+Con1fy                                         
+Con1fz    
+Con2fx     
+Con2fy                                         
+Con2fz  
+Con2px     
+Con2py                                         
+Con2pz   
+Body1fx   
+Body1fy 
+Body1fz 
+Body1mx
+Body1my
+Body1mz                                
+------------------------- need this line --------------------------------------                                                                                     
+

tests/test_line.py

@@ -0,0 +1,55 @@
+# tests MoorPy Line functionality and results (work in progres)
+
+import pytest
+
+from numpy.testing import assert_allclose
+
+import numpy as np
+import moorpy as mp
+#from moorpy.MoorProps import getLineProps
+from moorpy.helpers import getLineProps
+
+import matplotlib.pyplot as plt
+
+
+inCBs = [0, 1.0, 10.0]  # friction coefficients as inputs for test_seabed
+
+
+
+def test_line_stiffness():
+    '''Checks stiffness of mooring lines.'''
+
+
+
+if __name__ == '__main__':
+
+    import moorpy as mp
+    import matplotlib.pyplot as plt
+
+    ms = mp.System(depth=100)
+    ms.setLineType(100, 'chain', name='chain')
+
+    ms.addPoint(1,  [1, 0, -100]) # anchor point
+    ms.addPoint(-1, [0, 0, 0]) # moving point
+
+    ms.addLine(99, 'chain', pointA=1, pointB=2)
+
+    ms.initialize()
+
+    fig, ax = ms.plot()
+
+    ms.solveEquilibrium()
+    f0 = ms.pointList[1].getForces()
+    print(f0)
+    print(ms.lineList[0].KA[1,1])
+
+    ms.pointList[1].setPosition([0,0.1,0])
+    ms.solveEquilibrium()
+    f1 = ms.pointList[1].getForces()
+    print(f1)
+    print(ms.lineList[0].KA[1,1])
+
+    ms.plot(ax=ax, color='red')
+
+    plt.show()
+