ParamsSnap

class PlasmaCalcs.dimensions.snaps.ParamsSnap(s=None, i=None, *, t=None, params=None)

Bases: DictlikeFromKeysAndGetitem, Snap

single snapshot with associated parameters, saved in self.params;

self also behaves like a dict with params keys & values.

(Useful if each snapshot has a possibly-different set of parameters.)

s: the label (str) of the snapshot. if None, cannot convert to str.
i: the “index” (int) of the snapshot (within a SnapList). if None, cannot convert to int.
t: time at this snapshot [‘raw’ units]
params: dict of parameters at this snapshot. if None, make empty dict.

The “index” should only be meaningful in the context of a SnapList

The “label” should be the str name for this snapshot

- unique within context (e.g. there’s only one “snapshot 1” in a simulation)

- easiest to use str int labels (e.g. “snapshot 1” –> label=”1”)

Methods

`__eq__`(v)	return self==v.
`__getitem__`(key)	equivalent to self.params[key]
`__init_subclass__`(*[, _serial_typename])	register cls as a subclass of XarrayIoSerializable.
`__iter__`()	raises TypeError; use .keys(), .values(), or .items() instead.
`array_equals`(other)	return whether self == other (which is assumed to be a numpy array or xarray.DataArray).
`copy`(**kw_init)	return a copy of self.
`copy_add_t`(t_add)	create a copy of self but with t increased by t_add.
`datetimestamp`(calculator, **kw_datetimestamp)	returns the datetime associated with this snap for this calculator.
`deserialize`(serial)	creates an XarrayIoSerializable object from a serialized representation.
`equal_except_i`(v)	returns whether self == v (another DimensionValue), ignoring i.
`exists_for`(calculator)	returns whether this snap exists for this calculator.
`file_path`(calculator)	returns the abspath to the file associated with this snap for this calculator.
`file_s`(calculator)	returns the str used when determining file related to this snap.
`file_snap`(calculator)	returns the snap used when determining file related to this snap.
`from_dict`(d, *[, ignore_dt])	return cls from dict d.
`get`(key[, default])	return self[key].
`items`()	return tuple of (key, value) pairs corresponding to self.keys() and self.values().
`keys`()	return tuple of keys of self.params
`lookup_dict`()	returns dict for looking up self within a DimensionValueList, given int, str, or self.
`register_type`(cls_to_register[, ...])	register cls_to_register as a serializable subclass of XarrayIoSerializable.
`serialize`()	return dict of info about self, including 'typename' key.
`to_dict`()	return dictionary of info about self.
`values`()	return tuple of values corresponding to self.keys().
`with_i`(i)	return copy of self with i=i, or self if self.i==i already.
`_assert_array_equals`(other)	raise DimensionValueError unless self.array_equals(other).
`_assert_single`(vals, *[, meaning])	assert len(vals)==1.
`_repr_simple`()	return simple repr for self: Classname(s, i).

Attributes

`SERIAL_TYPES`
`ndim`
`size`

__eq__(v): return self==v. Equal if:

- v is an instance of type(self), and

all kw from both self._kw_eq and v._kw_eq have the same values.

(any kw missing attrs will be treated as UNSET.)

For DimensionValue, just compares self.s==v.s and self.i==v.i.

Subclasses may add more kwargs to compare by altering _kw_def.

- or, self.s == v or self.i == v, and v is not another DimensionValue

- or, v is a DimensionSingleValueSpecifier and v.checker(self) gives True.

Not equal if v is a DimensionValue but not an instance of type(self),

e.g. class Fluid(DimensionValue):…; class Snap(DimensionValue):…;

Fluid(‘H’, 0) != Snap(‘H’, 0).

__getitem__(key): equivalent to self.params[key]

classmethod __init_subclass__(*, _serial_typename=None, **kw)

register cls as a subclass of XarrayIoSerializable.

_serial_typename: None or str

name to use for this type, for serialization purposes.
None –> use cls.__name__.
This method also sets cls._serial_typename = _serial_typename.

__iter__(): raises TypeError; use .keys(), .values(), or .items() instead.

_assert_array_equals(other): raise DimensionValueError unless self.array_equals(other).

classmethod _assert_single(vals, *, meaning='value'): assert len(vals)==1. Raise DimensionKeyError if len==0; DimensionValueError if len>=2.

meaning can be provided to clarify what vals should represent, in case of crash;

error message will be ‘expected exactly 1 {meaning}, but got {len(vals)}’.

This check tends to make more sense coming from a DimensionValueList,

but it is convenient to attach here too in case of using isel from an array.

_dimension_key_error: alias of SnapKeyError

_dimension_value_error: alias of SnapValueError

_repr_simple(): return simple repr for self: Classname(s, i).

if s is None, use Classname(i) instead.

if i is None, use Classname(s, i=None) instead.

Called when using PlasmaCalcs.tools.repr_simple.

array_equals(other): return whether self == other (which is assumed to be a numpy array or xarray.DataArray).

return False if other.size != 1. Else, compare to other.item().

(Extremely convenient if comparing to xarray DataArray or numpy array,

with potentially unknown size / dimensionality.

Also, convenient if “self” might be DimensionValueList instead,

because DimensionValueList also provides an array_equals method.)

copy(**kw_init): return a copy of self. Can provide new kwargs here to override old values in result.

E.g. self.copy(i=7) makes a copy of self but with i=7 instead of self.i.

copy_add_t(t_add): create a copy of self but with t increased by t_add.

Equivalent to self.copy(t=self.t + t_add).

Provided separately for convenience; shifting t can be quite useful.

datetimestamp(calculator, **kw_datetimestamp): returns the datetime associated with this snap for this calculator.

Here, just return datetimestamp(self.file_path(calculator)).

static deserialize(serial)

creates an XarrayIoSerializable object from a serialized representation.

serial: dict or str

str –> convert to dict via ast.literal_eval.

dict must contain ‘typename’ key.

The output here will be an instance of XarrayIoSerializable.SERIAL_TYPES[typename]

equal_except_i(v): returns whether self == v (another DimensionValue), ignoring i.

equal if v is an instance of type(self) and

all kw from both self._kw_eq and v._kw_eq have the same values.

(any kw missing attrs will be treated as UNSET.)

For DimensionValue: self.s==v.s and self.i==v.i. Subclasses may add more.

exists_for(calculator): returns whether this snap exists for this calculator.

Here, just return self is not MISSING_SNAP. subclass should override if desired.

file_path(calculator): returns the abspath to the file associated with this snap for this calculator.

Here, just return calculator.snap_filepath(self).

file_s(calculator): returns the str used when determining file related to this snap.

Here, just return str(self). subclass should override if desired.

file_snap(calculator): returns the snap used when determining file related to this snap.

Here, just returns self. Subclasses might override.

classmethod from_dict(d, *, ignore_dt=True): return cls from dict d. d should NOT have ‘typename’ key.

Use cls.deserialize(d) instead if d has ‘typname’ key.

ignore_dt: bool

whether to ignore ‘dt’ key from d.

This exists for backwards compatibility when reading older files;

Snap previously accepted ‘dt’ key but doesn’t anymore.

get(key, default=UNSET): return self[key]. if default is provided and self[key] doesn’t exist, return default.

items(): return tuple of (key, value) pairs corresponding to self.keys() and self.values().

keys(): return tuple of keys of self.params

lookup_dict(): returns dict for looking up self within a DimensionValueList, given int, str, or self.

(used by DimensionValueList.lookup_dict)

static register_type(cls_to_register, _serial_typename=None): register cls_to_register as a serializable subclass of XarrayIoSerializable.

_serial_typename: str or None

name to use for serialization. if None, use cls_to_register.__name__.

serialize(): return dict of info about self, including ‘typename’ key.

to_dict(): return dictionary of info about self. Attribute values for keys in self._kw_def.

e.g. if _kw_def={‘s’, ‘i’}: result = {‘s’: self.s, ‘i’: self.i}

values(): return tuple of values corresponding to self.keys().

with_i(i): return copy of self with i=i, or self if self.i==i already.