def cost(x):
g_mod=modified_node_grid(g,n,x)
# This one sucked:
if 0:
cost=np.sum([link_cost(g_mod,j)
for j in links])
# mimic report_orthogonality()
cost=0
if 1:
nsi=4 # quads only right now...
centers=g_mod.cells_center(mode='sequential')
# this is somehow making the mean and max circumcenter error larger!
offsets = g_mod.nodes['x'][g_mod.cells['nodes'][cells,:nsi]] - centers[cells,None,:]
dists = utils.mag(offsets)
# maybe lets small cells take over too much
# cost += np.mean( np.std(dists,axis=1) / np.mean(dists,axis=1) )
# different, but not much better
# cost += np.mean( np.std(dists,axis=1) )
base_cost=np.max( np.std(dists,axis=1) )
if verbose:
print " Circum. cost: %f"%(base_cost)
cost += base_cost
if w_area>0 and len(links):
# this helps a bit, but sometimes getting good areas
# means distorting the shapes
A=g_mod.cells_area()
pairs=A[ g.edges['cells'][links] ]
diffs=(pairs[:,0]-pairs[:,1])/pairs.mean(axis=1)
area_cost=w_area*np.sum(diffs**2)
if verbose:
print " Area cost: %f"%area_cost
cost+=area_cost
if w_length>0:
# if it's not too far off, this makes it look nicer at
# the expense of circ. errors
l_cost=0
g_mod.update_cell_edges()
lengths=g_mod.edges_length()
for c in cells:
e=g_mod.cell_to_edges(c)
if 0:
# maybe that's too much leeway, and
# the user should have to specify aspect ratios
if len(e)==4:
a,b,c,d=lengths[e]
l_cost+=( ((a-c)/(a+c))**2 +
((b-d)/(b+d))**2 )
else:
lmean=lengths.mean()
l_cost+= np.sum( (lengths-lmean)**2 )
if verbose:
print " Length cost: %f"%( w_length*l_cost )
cost+=w_length*l_cost
if w_angle>0:
# interior angle of cells
deltas=np.diff(g_mod.nodes['x'][triples],axis=1)
angles=np.diff( np.arctan2( deltas[:,:,1], deltas[:,:,0] ),axis=1) % (2*np.pi) * 180/np.pi
angle_cost=w_angle*np.sum( (angles-90)**2 )
if verbose:
print " Angle cost: %f"%angle_cost
cost+=angle_cost
if w_cangle>0:
cangle_cost=0
for c in cells:
nodes=g.cell_to_nodes(c)
deltas=g_mod.nodes['x'][nodes] - g_mod.cells_center()[c]
angles=np.arctan2(deltas[:,1],deltas[:,0]) * 180/np.pi
cds=utils.cdiff(angles) % 360.
cangle_cost+=np.sum( (cds-90)**4 )
if verbose:
print " CAngle cost: %f"%( w_cangle*cangle_cost )
cost+=w_cangle*cangle_cost
return cost