def __init__(self, isfld, isxmap, isdmap, evlmap, hdrtxt, hdrmap):
"""Initialise configuration object.
Parameters
----------
isfld : list
List of field names for iteration statistics namedtuple
isxmap : dict
Dictionary mapping iteration statistics namedtuple field names
to field names in corresponding X step object iteration
statistics namedtuple
isdmap : dict
Dictionary mapping iteration statistics namedtuple field names
to field names in corresponding D step object iteration
statistics namedtuple
evlmap : dict
Dictionary mapping iteration statistics namedtuple field names
to labels in the dict returned by :meth:`DictLearn.evaluate`
hdrtxt : list
List of column header titles for verbose iteration statistics
display
hdrmap : dict
Dictionary mapping column header titles to IterationStats entries
"""
self.IterationStats = collections.namedtuple('IterationStats', isfld)
self.isxmap = isxmap
self.isdmap = isdmap
self.evlmap = evlmap
self.hdrtxt = hdrtxt
self.hdrmap = hdrmap
# Call utility function to construct status display formatting
self.hdrstr, self.fmtstr, self.nsep = util.solve_status_str(
hdrtxt, type(self).fwiter, type(self).fpothr)
def display_start(self):
"""Set up status display if option selected. NB: this method assumes
that the first entry is the iteration count and the last is
the rho value.
"""
if self.opt['Verbose']:
# If AutoRho option enabled rho is included in iteration status
if self.opt['AutoRho', 'Enabled']:
hdrtxt = type(self).hdrtxt()
else:
hdrtxt = type(self).hdrtxt()[0:-1]
# Call utility function to construct status display formatting
hdrstr, fmtstr, nsep = util.solve_status_str(
hdrtxt,
type(self).fwiter,
type(self).fpothr)
# Print header and separator strings
if self.opt['StatusHeader']:
print(hdrstr)
print("-" * nsep)
else:
fmtstr, nsep = '', 0
return fmtstr, nsep
def solve(self):
"""Start (or re-start) optimisation. This method implements the
framework for the alternation between `X` and `D` updates in a
dictionary learning algorithm.
If option ``Verbose`` is ``True``, the progress of the
optimisation is displayed at every iteration. At termination
of this method, attribute :attr:`itstat` is a list of tuples
representing statistics of each iteration.
Attribute :attr:`timer` is an instance of :class:`.util.Timer`
that provides the following labelled timers:
``init``: Time taken for object initialisation by
:meth:`__init__`
``solve``: Total time taken by call(s) to :meth:`solve`
``solve_wo_func``: Total time taken by call(s) to
:meth:`solve`, excluding time taken to compute functional
value and related iteration statistics
"""
# Construct tuple of status display column titles and set status
# display strings
hdrtxt = ['Itn', 'Fnc', 'DFid', u('Regℓ1')]
hdrstr, fmtstr, nsep = util.solve_status_str(hdrtxt,
type(self).fwiter,
type(self).fpothr)
# Print header and separator strings
if self.opt['Verbose']:
if self.opt['StatusHeader']:
print(hdrstr)
print("-" * nsep)
# Reset timer
self.timer.start(['solve', 'solve_wo_eval'])
# Create process pool
if self.nproc > 0:
self.pool = mp.Pool(processes=self.nproc)
for self.j in range(self.j, self.j + self.opt['MaxMainIter']):
# Perform a set of update steps
self.step()
# Evaluate functional
self.timer.stop('solve_wo_eval')
fnev = self.evaluate()
self.timer.start('solve_wo_eval')
# Record iteration stats
tk = self.timer.elapsed('solve')
itst = self.IterationStats(*((self.j, ) + fnev + (tk, )))
self.itstat.append(itst)
# Display iteration stats if Verbose option enabled
if self.opt['Verbose']:
print(fmtstr % itst[:-1])
# Call callback function if defined
if self.opt['Callback'] is not None:
if self.opt['Callback'](self):
break
# Clean up process pool
if self.nproc > 0:
self.pool.close()
self.pool.join()
# Increment iteration count
self.j += 1
# Record solve time
self.timer.stop(['solve', 'solve_wo_eval'])
# Print final separator string if Verbose option enabled
if self.opt['Verbose'] and self.opt['StatusHeader']:
print("-" * nsep)
# Return final dictionary
return self.getdict()