def fit_bc(pF, theta, count=20, verbose=False):
"""Fits a Brooks-Corey retention curve into data
pF: a sequence of pF values
theta: an array of water contents
"""
theta_mean = np.mean(theta)
ns_denom = np.sum((theta - theta_mean)**2)
best_f = 1e12
for i in range(count):
x0 = np.array((random.uniform(0.01, 1.0), random.uniform(1.0, 20),
random.uniform(0.01, 1.0)))
x_opt, f_opt, n_iter, n_eval, warn = opt.fmin(get_error_bc,
x0=x0,
args=(pF, theta),
full_output=1,
disp=0)
if f_opt < best_f:
if verbose:
print "%i: x=%s f=%0.12g iter=%i, eval=%i" % (
i, x_opt, 1 - f_opt / ns_denom, n_iter, n_eval)
bc = cmf.BrooksCoreyRetentionCurve(1., x_opt[0], x_opt[1],
x_opt[2])
best_f = f_opt
return bc, 1 - best_f / ns_denom
def soiltype(depth):
"""
Creates a retention curve for a depth below ground
using an exponential Ksat decline
:param depth: depth below ground in m
:return: Retention curve
"""
return cmf.BrooksCoreyRetentionCurve(ksat=15 * np.exp(-depth),
porosity=0.5,
_b=5.5,
theta_x=0.35)
def _create_cells(self,d_init_pot=0.3):
"""
Creates an object for each cell which consists of vertical layers
Parameters
----------
d_init_pot : float, optional
Delta in matric potential subtracted from the initial value (0.3 would subtract 0.3 from the standard value in each layer) [m]. The default is 0.3.
Returns
-------
None.
"""
for i in range(self.ncell):
c: cmf.Cell = self.NewCell(i * self.length / self.ncell, 0,
self.depth + (i-0) * self.slope_per_cell,
self.length / self.ncell * self.width, True)
if i:
c.topology.AddNeighbor(self[i - 1], self.width)
self.retention_curve = cmf.BrooksCoreyRetentionCurve(ksat=self.Ksat,
porosity=self.porosity,
_b=self.b,
theta_x=0.20,
psi_x=cmf.pF_to_waterhead(2.5))
list_z = list()
for zi in np.arange(0,self.depth, self.dz):
c.add_layer(zi+self.dz, self.retention_curve)
list_z.append(zi+self.dz)
c.install_connection(cmf.Richards)
c.saturated_depth=self.depth-(self.init_z_interpol-self.bottom)[i]
for ii,li in enumerate(c.layers):
if list_z[ii] <= self.depth-(self.init_z_interpol-self.bottom)[i]:
li.potential -= d_init_pot
del list_z
c.surfacewater.puddledepth = 0.001
c.surfacewater.nManning = self.mannings_n
def get_error_bc(params, pF, theta):
bc = cmf.BrooksCoreyRetentionCurve(1, params[0], params[1], params[2])
model_wetness = bc.Wetness_pF(pF)
err = np.sum((theta - params[0] * model_wetness)**2)
return err
def soiltype(depth):
return cmf.BrooksCoreyRetentionCurve(ksat=15*np.exp(-d),
porosity=0.5,
_b=5.5,
theta_x=0.35)