Files
simpeg/SimPEG/inverse/Inversion.py
T
2013-11-07 16:27:12 -08:00

212 lines
6.8 KiB
Python

import numpy as np
import scipy.sparse as sp
import SimPEG
from SimPEG.utils import sdiag, mkvc, setKwargs, checkStoppers
class Inversion(object):
"""docstring for Inversion"""
maxIter = 10
name = 'SimPEG Inversion'
def __init__(self, prob, reg, opt, **kwargs):
setKwargs(self, **kwargs)
self.prob = prob
self.reg = reg
self.opt = opt
self.opt.parent = self
self.stoppers = [SimPEG.inverse.StoppingCriteria.iteration, SimPEG.inverse.StoppingCriteria.phi_d_target_Inversion]
# Check if we have inserted printers into the optimization
if not np.any([p is SimPEG.inverse.IterationPrinters.phi_d for p in self.opt.printers]):
self.opt.printers.insert(1,SimPEG.inverse.IterationPrinters.beta)
self.opt.printers.insert(2,SimPEG.inverse.IterationPrinters.phi_d)
self.opt.printers.insert(3,SimPEG.inverse.IterationPrinters.phi_m)
self.opt.stoppers.append(SimPEG.inverse.StoppingCriteria.phi_d_target_Minimize)
@property
def Wd(self):
"""
Standard deviation weighting matrix.
"""
if getattr(self,'_Wd',None) is None:
eps = np.linalg.norm(mkvc(self.prob.dobs),2)*1e-5
self._Wd = 1/(abs(self.prob.dobs)*self.prob.std+eps)
return self._Wd
@property
def phi_d_target(self):
"""
target for phi_d
By default this is the number of data.
Note that we do not set the target if it is None, but we return the default value.
"""
if getattr(self, '_phi_d_target', None) is None:
return self.prob.dobs.size #
return self._phi_d_target
@phi_d_target.setter
def phi_d_target(self, value):
self._phi_d_target = value
def run(self, m0):
m = m0
self._iter = 0
self._beta = None
while True:
self._beta = self.getBeta()
m = self.opt.minimize(self.evalFunction,m)
self._iter += 1
if self.stoppingCriteria(): break
return m
beta0 = 1.e2
beta_coolingFactor = 5.
def getBeta(self):
if self._beta is None:
return self.beta0
return self._beta / self.beta_coolingFactor
def stoppingCriteria(self):
return checkStoppers(self, self.stoppers)
def evalFunction(self, m, return_g=True, return_H=True):
u = self.prob.field(m)
phi_d = self.dataObj(m, u)
phi_m = self.reg.modelObj(m)
self.phi_d = phi_d
self.phi_m = phi_m
f = phi_d + self._beta * phi_m
out = (f,)
if return_g:
phi_dDeriv = self.dataObjDeriv(m, u=u)
phi_mDeriv = self.reg.modelObjDeriv(m)
g = phi_dDeriv + self._beta * phi_mDeriv
out += (g,)
if return_H:
def H_fun(v):
phi_d2Deriv = self.dataObj2Deriv(m, v, u=u)
phi_m2Deriv = self.reg.modelObj2Deriv(m)*v
return phi_d2Deriv + self._beta * phi_m2Deriv
operator = sp.linalg.LinearOperator( (m.size, m.size), H_fun, dtype=float )
out += (operator,)
return out if len(out) > 1 else out[0]
def dataObj(self, m, u=None):
"""
:param numpy.array m: geophysical model
:param numpy.array u: fields
:rtype: float
:return: data misfit
The data misfit using an l_2 norm is:
.. math::
\mu_\\text{data} = {1\over 2}\left| \mathbf{W} \circ (\mathbf{d}_\\text{pred} - \mathbf{d}_\\text{obs}) \\right|_2^2
Where P is a projection matrix that brings the field on the full domain to the data measurement locations;
u is the field of interest; d_obs is the observed data; and W is the weighting matrix.
"""
# TODO: ensure that this is a data is vector and Wd is a matrix.
R = self.Wd*self.prob.dataResidual(m, u=u)
R = mkvc(R)
return 0.5*np.vdot(R, R)
def dataObjDeriv(self, m, u=None):
"""
:param numpy.array m: geophysical model
:param numpy.array u: fields
:rtype: numpy.array
:return: data misfit derivative
The data misfit using an l_2 norm is:
.. math::
\mu_\\text{data} = {1\over 2}\left| \mathbf{W} \circ (\mathbf{d}_\\text{pred} - \mathbf{d}_\\text{obs}) \\right|_2^2
If the field, u, is provided, the calculation of the data is fast:
.. math::
\mathbf{d}_\\text{pred} = \mathbf{Pu(m)}
\mathbf{R} = \mathbf{W} \circ (\mathbf{d}_\\text{pred} - \mathbf{d}_\\text{obs})
Where P is a projection matrix that brings the field on the full domain to the data measurement locations;
u is the field of interest; d_obs is the observed data; and W is the weighting matrix.
The derivative of this, with respect to the model, is:
.. math::
\\frac{\partial \mu_\\text{data}}{\partial \mathbf{m}} = \mathbf{J}^\\top \mathbf{W \circ R}
"""
if u is None:
u = self.prob.field(m)
R = self.Wd*self.prob.dataResidual(m, u=u)
dmisfit = self.prob.Jt(m, self.Wd * R, u=u)
return dmisfit
def dataObj2Deriv(self, m, v, u=None):
"""
:param numpy.array m: geophysical model
:param numpy.array u: fields
:rtype: numpy.array
:return: data misfit derivative
The data misfit using an l_2 norm is:
.. math::
\mu_\\text{data} = {1\over 2}\left| \mathbf{W} \circ (\mathbf{d}_\\text{pred} - \mathbf{d}_\\text{obs}) \\right|_2^2
If the field, u, is provided, the calculation of the data is fast:
.. math::
\mathbf{d}_\\text{pred} = \mathbf{Pu(m)}
\mathbf{R} = \mathbf{W} \circ (\mathbf{d}_\\text{pred} - \mathbf{d}_\\text{obs})
Where P is a projection matrix that brings the field on the full domain to the data measurement locations;
u is the field of interest; d_obs is the observed data; and W is the weighting matrix.
The derivative of this, with respect to the model, is:
.. math::
\\frac{\partial \mu_\\text{data}}{\partial \mathbf{m}} = \mathbf{J}^\\top \mathbf{W \circ R}
\\frac{\partial^2 \mu_\\text{data}}{\partial^2 \mathbf{m}} = \mathbf{J}^\\top \mathbf{W \circ W J}
"""
if u is None:
u = self.prob.field(m)
R = self.Wd*self.prob.dataResidual(m, u=u)
# TODO: abstract to different norms a little cleaner.
# \/ it goes here. in l2 it is the identity.
dmisfit = self.prob.Jt_approx(m, self.Wd * self.Wd * self.prob.J_approx(m, v, u=u), u=u)
return dmisfit