From e9a5b0f18b33c1e16238721eebd815b54f98efec Mon Sep 17 00:00:00 2001
From: Martin Reinecke <martin@mpa-garching.mpg.de>
Date: Sun, 1 Apr 2018 13:55:42 +0200
Subject: [PATCH] make inverse_draw_sample() largely obsolete
---
nifty4/operators/diagonal_operator.py | 17 +++++------------
nifty4/operators/endomorphic_operator.py | 15 +++++++++------
nifty4/operators/inversion_enabler.py | 17 ++++++-----------
nifty4/operators/operator_adapter.py | 11 +++--------
nifty4/operators/sandwich_operator.py | 7 +++++--
nifty4/operators/scaling_operator.py | 10 +++-------
nifty4/operators/sum_operator.py | 8 +++++---
7 files changed, 36 insertions(+), 49 deletions(-)
diff --git a/nifty4/operators/diagonal_operator.py b/nifty4/operators/diagonal_operator.py
index c2d0b5dd7..9c3652226 100644
--- a/nifty4/operators/diagonal_operator.py
+++ b/nifty4/operators/diagonal_operator.py
@@ -174,21 +174,14 @@ class DiagonalOperator(EndomorphicOperator):
raise ValueError("bad operator flipping mode")
return res
- def draw_sample(self, dtype=np.float64):
+ def draw_sample(self, from_inverse=False, dtype=np.float64):
if (np.issubdtype(self._ldiag.dtype, np.complexfloating) or
(self._ldiag <= 0.).any()):
raise ValueError("operator not positive definite")
res = Field.from_random(random_type="normal", domain=self._domain,
dtype=dtype)
- res.local_data[()] *= np.sqrt(self._ldiag)
- return res
-
- def inverse_draw_sample(self, dtype=np.float64):
- if (np.issubdtype(self._ldiag.dtype, np.complexfloating) or
- (self._ldiag <= 0.).any()):
- raise ValueError("operator not positive definite")
-
- res = Field.from_random(random_type="normal", domain=self._domain,
- dtype=dtype)
- res.local_data[()] /= np.sqrt(self._ldiag)
+ if from_inverse:
+ res.local_data[()] /= np.sqrt(self._ldiag)
+ else:
+ res.local_data[()] *= np.sqrt(self._ldiag)
return res
diff --git a/nifty4/operators/endomorphic_operator.py b/nifty4/operators/endomorphic_operator.py
index e456923c0..0046d8986 100644
--- a/nifty4/operators/endomorphic_operator.py
+++ b/nifty4/operators/endomorphic_operator.py
@@ -36,12 +36,19 @@ class EndomorphicOperator(LinearOperator):
for endomorphic operators."""
return self.domain
- def draw_sample(self, dtype=np.float64):
+ def draw_sample(self, from_inverse=False, dtype=np.float64):
"""Generate a zero-mean sample
Generates a sample from a Gaussian distribution with zero mean and
covariance given by the operator.
+ Parameters
+ ----------
+ from_inverse : bool (default : False)
+ if True, the sample is drawn from the inverse of the operator
+ dtype : numpy datatype (default : numpy.float64)
+ the data type to be used for the sample
+
Returns
-------
Field
@@ -59,8 +66,4 @@ class EndomorphicOperator(LinearOperator):
-------
A sample from the Gaussian of given covariance
"""
- if self.capability & self.INVERSE_TIMES:
- x = self.draw_sample(dtype)
- return self.inverse_times(x)
- else:
- raise NotImplementedError
+ return self.draw_sample(True, dtype)
diff --git a/nifty4/operators/inversion_enabler.py b/nifty4/operators/inversion_enabler.py
index 774318cb8..dbdd59314 100644
--- a/nifty4/operators/inversion_enabler.py
+++ b/nifty4/operators/inversion_enabler.py
@@ -20,11 +20,11 @@ from ..minimization.quadratic_energy import QuadraticEnergy
from ..minimization.iteration_controller import IterationController
from ..field import Field
from ..logger import logger
-from .linear_operator import LinearOperator
+from .endomorphic_operator import EndomorphicOperator
import numpy as np
-class InversionEnabler(LinearOperator):
+class InversionEnabler(EndomorphicOperator):
"""Class which augments the capability of another operator object via
numerical inversion.
@@ -80,14 +80,9 @@ class InversionEnabler(LinearOperator):
logger.warning("Error detected during operator inversion")
return r.position
- def draw_sample(self, dtype=np.float64):
+ def draw_sample(self, from_inverse=False, dtype=np.float64):
try:
- return self._op.draw_sample(dtype)
+ return self._op.draw_sample(from_inverse, dtype)
except:
- return self(self._op.inverse_draw_sample(dtype))
-
- def inverse_draw_sample(self, dtype=np.float64):
- try:
- return self._op.inverse_draw_sample(dtype)
- except:
- return self.inverse_times(self._op.draw_sample(dtype))
+ samp = self._op.draw_sample(not from_inverse, dtype)
+ return self.inverse_times(samp) if from_inverse else self(samp)
diff --git a/nifty4/operators/operator_adapter.py b/nifty4/operators/operator_adapter.py
index 61ce31865..036045e79 100644
--- a/nifty4/operators/operator_adapter.py
+++ b/nifty4/operators/operator_adapter.py
@@ -49,12 +49,7 @@ class OperatorAdapter(LinearOperator):
def apply(self, x, mode):
return self._op.apply(x, self._modeTable[self._mode][self._ilog[mode]])
- def draw_sample(self, dtype=np.float64):
+ def draw_sample(self, from_inverse=False, dtype=np.float64):
if self._mode & self.INVERSE_BIT:
- return self._op.inverse_draw_sample(dtype)
- return self._op.draw_sample(dtype)
-
- def inverse_draw_sample(self, dtype=np.float64):
- if self._mode & self.INVERSE_BIT:
- return self._op.draw_sample(dtype)
- return self._op.inverse_draw_sample(dtype)
+ return self._op.draw_sample(not from_inverse, dtype)
+ return self._op.draw_sample(from_inverse, dtype)
diff --git a/nifty4/operators/sandwich_operator.py b/nifty4/operators/sandwich_operator.py
index e324b135d..464072adb 100644
--- a/nifty4/operators/sandwich_operator.py
+++ b/nifty4/operators/sandwich_operator.py
@@ -48,5 +48,8 @@ class SandwichOperator(EndomorphicOperator):
def apply(self, x, mode):
return self._op.apply(x, mode)
- def draw_sample(self, dtype=np.float64):
- return self._bun.adjoint_times(self._cheese.draw_sample(dtype))
+ def draw_sample(self, from_inverse=False, dtype=np.float64):
+ if from_inverse:
+ raise ValueError("cannot draw from inverse of this operator")
+ return self._bun.adjoint_times(
+ self._cheese.draw_sample(from_inverse, dtype))
diff --git a/nifty4/operators/scaling_operator.py b/nifty4/operators/scaling_operator.py
index ddb8eaaae..cce8fee4b 100644
--- a/nifty4/operators/scaling_operator.py
+++ b/nifty4/operators/scaling_operator.py
@@ -93,14 +93,10 @@ class ScalingOperator(EndomorphicOperator):
def capability(self):
return self._all_ops
- def _sample_helper(self, fct, dtype):
+ def draw_sample(self, from_inverse=False, dtype=np.float64):
+ fct = self._factor
if fct.imag != 0. or fct.real <= 0.:
raise ValueError("operator not positive definite")
+ fct = 1./np.sqrt(fct) if from_inverse else np.sqrt(fct)
return Field.from_random(
random_type="normal", domain=self._domain, std=fct, dtype=dtype)
-
- def draw_sample(self, dtype=np.float64):
- return self._sample_helper(np.sqrt(self._factor), dtype)
-
- def inverse_draw_sample(self, dtype=np.float64):
- return self._sample_helper(1./np.sqrt(self._factor), dtype)
diff --git a/nifty4/operators/sum_operator.py b/nifty4/operators/sum_operator.py
index be36836af..e2d5d70f3 100644
--- a/nifty4/operators/sum_operator.py
+++ b/nifty4/operators/sum_operator.py
@@ -143,8 +143,10 @@ class SumOperator(LinearOperator):
res += op.apply(x, mode)
return res
- def draw_sample(self, dtype=np.float64):
- res = self._ops[0].draw_sample(dtype)
+ def draw_sample(self, from_inverse=False, dtype=np.float64):
+ if from_inverse:
+ raise ValueError("cannot draw from inverse of this operator")
+ res = self._ops[0].draw_sample(from_inverse, dtype)
for op in self._ops[1:]:
- res += op.draw_sample(dtype)
+ res += op.draw_sample(from_inverse, dtype)
return res
--
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