cache¶
Module for caching.
The basic concept of caching in Zfit builds on a “cacher”, that caches a certain value and that is dependent of “cache_dependents”. By implementing ZfitCachable, an object will be able to play both roles. And most importantly, it has a _cache dict, that contains all the cache.
Basic principle¶
A “cacher” adds any dependents that it may comes across with add_cache_dependents. For example,
for a loss this would be all pdfs and data. Since Space is immutable, there is no need to add this
as a dependent. This leads to the “cache_dependent” to register the “cacher” and to remember it.
In case, any “cache_dependent” changes in a way the cache of itself (and any “cacher”) is invalid, which is done in the simplest case by decorating a method with @invalidates_cache, the “cache_dependent”:
- clears it’s own cache with reset_cache_self and
- “clears” any “cacher”s cache with reset_cache(reseter=self), telling the “cacher” that it should reset the cache. This is also where more fine-grained control (depending on which “cache_dependent” calls reset_cache) can be brought into play.
Example with a pdf that caches the normalization:
class Parameter(Cachable):
def load(new_value): # does not require to build a new graph
# do something
@invalidates_cache
def change_limits(new_limits): # requires to build a new graph (as an example)
# do something
# create param1, param2 from `Parameter`
class MyPDF(Cachable):
def __init__(self, param1, param2):
self.add_cache_dependents([param1, param2])
def cached_func(...):
if self._cache.get('my_name') is None:
result = ... # calculations here
self._cache['my_name']
else:
result = self._cache['my_name']
return result
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class
zfit.util.cache.Cachable(*args, **kwargs)[source]¶ Bases:
zfit.util.cache.ZfitCachable-
add_cache_dependents(cache_dependents: Union[zfit.core.interfaces.ZfitCachable, Iterable[zfit.core.interfaces.ZfitCachable]], allow_non_cachable: bool = True)[source]¶ Add dependents that render the cache invalid if they change.
Parameters: - cache_dependents (ZfitCachable) –
- allow_non_cachable (bool) – If True, allow cache_dependents to be non-cachables. If False, any cache_dependents that is not a ZfitCachable will raise an error.
Raises: TypeError– if one of the cache_dependents is not a ZfitCachable _and_ allow_non_cachable if False.
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-
class
zfit.util.cache.ZfitCachable[source]¶ Bases:
object-
add_cache_dependents(cache_dependents, allow_non_cachable)[source]¶ Add dependents that render the cache invalid if they change.
Parameters: - cache_dependents (ZfitCachable) –
- allow_non_cachable (bool) – If True, allow cache_dependents to be non-cachables. If False, any cache_dependents that is not a ZfitCachable will raise an error.
Raises: TypeError– if one of the cache_dependents is not a ZfitCachable _and_ allow_non_cachable if False.
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