calliope.select.constraints
¶
Module Contents¶
Classes¶
Abstract base class. 

Abstract base class. 

Abstract base class for global (whole playlist) constraints. 

Abstract base class. 

Abstract base class. 

Apply an item constraint to every item in the playlist. 

Apply an item set constraint to some items in the playlist. 

The sum of 'prop' for all songs should be between 'vmin' and 'vmax'. 

Each song should have duration in range [min, max]. 

Playlist should be a specified number of seconds in duration. 

Playlist items should total a specified number of bytes in size. 
Functions¶

Objective function for value and target range [vmin, vmax] 
Attributes¶
 calliope.select.constraints.linear_score(value, vmin, vmax)¶
Objective function for value and target range [vmin, vmax]
Returns 1.0 if vmin <= value <= vmax, decreasing linearly to 0.0 as value tends towards 0.0 and vmax*2.
 class calliope.select.constraints.ItemConstraint(prop)¶
Bases:
Constraint
Abstract base class.
 Parameters
prop (str) –
 __repr__()¶
Return repr(self).
 abstract score_item(item)¶
Score how well item satisfies this constraint.
The score must be between 0.0 (doesn’t satisfy constraint) and 1.0 (satisfies it perfectly).
 Parameters
item (calliope.playlist.Item) –
 Return type
float
 abstract partition(collection)¶
Divide ‘collection’ into one ‘good’ and one or more ‘bad’ groups.
This is used to define the neighbourhood we search for a solution.
 Return type
 class calliope.select.constraints.GlobalConstraint¶
Bases:
Constraint
Abstract base class for global (whole playlist) constraints.
 abstract score_playlist(playlist)¶
Score how well playlist satisfies this constraint.
The score must be between 0.0 (doesn’t satisfy constraint) and 1.0 (satisfies it perfectly).
 class calliope.select.constraints.SetConstraint(prop, values)¶
Bases:
ItemConstraint
Abstract base class.
Simple set constraint, for properties with nominal (string) values.
An item satisfies the constraint if its value matches one member of values.
 Parameters
prop (str) –
values ([str]) –
 __repr__()¶
Return repr(self).
 score_item(item)¶
Score how well item satisfies this constraint.
The score must be between 0.0 (doesn’t satisfy constraint) and 1.0 (satisfies it perfectly).
 Parameters
item (calliope.playlist.Item) –
 Return type
float
 partition(collection)¶
Divide ‘collection’ into one ‘good’ and one or more ‘bad’ groups.
This is used to define the neighbourhood we search for a solution.
 class calliope.select.constraints.RangeConstraint(prop, vmin, vmax)¶
Bases:
ItemConstraint
Abstract base class.
Simple range constraint, for properties with numeric values.
An item scores 1.0 if vmin <= prop <= vmax. The score decreases linearly towards 0.0 as prop approaches 0 or 2*`vmax`.
t’s common to specify a single value by specifying vmin = vmax.
 Parameters
prop (str) –
vmin (float) –
vmax (float) –
 __repr__()¶
Return repr(self).
 score_item(item)¶
Score how well item satisfies this constraint.
The score must be between 0.0 (doesn’t satisfy constraint) and 1.0 (satisfies it perfectly).
 partition(collection)¶
Divide ‘collection’ into one ‘good’ and one or more ‘bad’ groups.
This is used to define the neighbourhood we search for a solution.
 class calliope.select.constraints.EachGlobalConstraint(item_constraint)¶
Bases:
GlobalConstraint
Apply an item constraint to every item in the playlist.
 Parameters
item_constraint (ItemConstraint) –
 __repr__()¶
Return repr(self).
 score_playlist(playlist)¶
Score how well playlist satisfies this constraint.
The score must be between 0.0 (doesn’t satisfy constraint) and 1.0 (satisfies it perfectly).
 partition(collection)¶
 class calliope.select.constraints.FractionGlobalConstraint(item_constraint, fmin, fmax)¶
Bases:
GlobalConstraint
Apply an item set constraint to some items in the playlist.
 Parameters
item_constraint (SetConstraint) –
fmin (float) –
fmax (float) –
 __repr__()¶
Return repr(self).
 score_playlist(playlist)¶
Score how well playlist satisfies this constraint.
The score must be between 0.0 (doesn’t satisfy constraint) and 1.0 (satisfies it perfectly).
 partition(collection)¶
 class calliope.select.constraints.SumGlobalConstraint(prop, vmin, vmax)¶
Bases:
GlobalConstraint
,RangeConstraint
The sum of ‘prop’ for all songs should be between ‘vmin’ and ‘vmax’.
Simple range constraint, for properties with numeric values.
An item scores 1.0 if vmin <= prop <= vmax. The score decreases linearly towards 0.0 as prop approaches 0 or 2*`vmax`.
t’s common to specify a single value by specifying vmin = vmax.
 __repr__()¶
Return repr(self).
 score_playlist(playlist)¶
Score how well playlist satisfies this constraint.
The score must be between 0.0 (doesn’t satisfy constraint) and 1.0 (satisfies it perfectly).
 partition(collection)¶
Divide ‘collection’ into one ‘good’ and one or more ‘bad’ groups.
This is used to define the neighbourhood we search for a solution.
 class calliope.select.constraints.ItemDurationConstraint(vmin, vmax)¶
Bases:
EachGlobalConstraint
Each song should have duration in range [min, max].
 PROP = duration¶
 class calliope.select.constraints.PlaylistDurationConstraint(vmin, vmax)¶
Bases:
SumGlobalConstraint
Playlist should be a specified number of seconds in duration.
Simple range constraint, for properties with numeric values.
An item scores 1.0 if vmin <= prop <= vmax. The score decreases linearly towards 0.0 as prop approaches 0 or 2*`vmax`.
t’s common to specify a single value by specifying vmin = vmax.
 PROP = duration¶
 class calliope.select.constraints.PlaylistDiskSpaceConstraint(vmin, vmax)¶
Bases:
SumGlobalConstraint
Playlist items should total a specified number of bytes in size.
Simple range constraint, for properties with numeric values.
An item scores 1.0 if vmin <= prop <= vmax. The score decreases linearly towards 0.0 as prop approaches 0 or 2*`vmax`.
t’s common to specify a single value by specifying vmin = vmax.
 PROP = album.size_mb¶
 calliope.select.constraints.BY_NAME¶