def adaptMesh(geom, v, t, b, nE, metric, diameter=None):
'''
Adapt mesh with a metric defined on vertices
'''
assert metric.shape == (v.shape[0], 2, 2)
# compute initial metric
c, d = centerDiameter(geom)
if diameter is not None: d = diameter
m = (((v-c)**2).sum(1) + 5*d**2)**-2
# adjust diagonal for positive definiteness and limit anisotropy
mxx, myy, mxy = metric[:,0,0], metric[:,1,1], metric[:,0,1]
mMin = (mxx + myy) / 2. - sqrt((mxx - myy)**2 / 4. + mxy**2)
mMax = (mxx + myy) / 2. + sqrt((mxx - myy)**2 / 4. + mxy**2)
mAdjust = maximum(mMax.max() * 1E-12, mMax*.001 - mMin)
mxx += mAdjust
myy += mAdjust
mMin += mAdjust
mMax += mAdjust
# adjust length ratio 1,000,000,000:1
maxOverMin = mMax.max() / mMax.min()
expFactor = minimum(1, log10(1E9) / log10(maxOverMin))
multFactor = mMax**(expFactor-1)
m *= multFactor
# combine
m = transpose([m * mxx, m * myy, m * mxy])
return _ani.mbaMesh(v, t, b, nE, m)
def initMesh(geom, nE, diameter=None):
'''
Generate mesh with a simple metric
'''
c, d = centerDiameter(geom)
if diameter is not None: d = diameter
v, t, b = _ani.aftMesh(geom, d)
# compute initial metric
metric = (((v-c)**2).sum(1) + 5*d**2)**-2
metric = transpose([metric, metric, metric * 0])
return _ani.mbaMesh(v, t, b, nE, metric)
