import logging
from textwrap import dedent
from ..tecutil import _tecutil, _tecutil_connector
from ..constant import *
from ..exception import *
from .. import layout, session, tecutil
from . import array
log = logging.getLogger(__name__)
[docs]
@tecutil.lock_attributes
class Variable(object):
"""Key value for a data array within a `Dataset <tecplot.data.Dataset>`.
`Variables <Variable>` can be identified (uniquely) by the index within
their parent `Dataset <tecplot.data.Dataset>` or (non-uniquely) by name. In general, a `Zone
<data_access>` must also be selected to access the underlying data array.
This object is used by several style controlling classes such as contours
and vectors. The following example sets the contour variable for the first
contour group to the first variable named 'S'::
>>> plot.contour(0).variable = dataset.variable('S')
"""
def __init__(self, uid, dataset):
self.uid = uid
self.dataset = dataset
@property
def _cache(self):
if _tecutil_connector.suspended:
_tecutil_connector._delete_caches.append(self._delete_cache)
return True
else:
return False
def _delete_cache(self):
attrs = ['_index']
for attr in attrs:
try:
delattr(self, attr)
except AttributeError:
pass
def __str__(self):
"""Brief string representation.
Returns:
`str`: Brief representation of this `Variable`, showing
`Zones <data_access>`.
Example::
>>> p = dataset.variable('Pressure')
>>> print(p)
Pressure
"""
return self.name
def __repr__(self):
"""Executable string representation.
Returns:
`str`: Internal representation of this `Variable`.
The string returned can be executed to generate a
clone of this `Variable` object::
>>> x = dataset.variable('x')
>>> print(repr(x))
Variable(uid=41, Dataset(uid=21, frame=Frame(uid=11,
page=Page(uid=1)))
>>> exec('x_clone = '+repr(x))
>>> x_clone
Variable(uid=41, Dataset(uid=21, frame=Frame(uid=11,
page=Page(uid=1)))
>>> x == x_clone
True
"""
return 'Variable(uid={uid}, dataset={dataset})'.format(
uid=self.uid, dataset=repr(self.dataset))
def __eq__(self, other):
"""Checks for equality in the |Tecplot Engine|.
Returns:
`bool`: `True` if the unique ID numbers are the same for both
`Variables <Variable>`.
"""
return self.uid == other.uid
def __ne__(self, other):
return not (self == other)
@property
def aux_data(self):
"""Auxiliary data for this variable.
Returns:
`AuxData`
This is the auxiliary data attached to the variable. Such data is
written to the layout file by default and can be retrieved later.
Example usage::
>>> frame = tp.active_frame()
>>> aux = frame.dataset.variable('X').aux_data
>>> aux['X_weighted_avg'] = '3.14159'
>>> print(aux['X_weighted_avg'])
3.14159
"""
return session.AuxData(self.dataset.frame, AuxDataObjectType.Variable,
self.index)
@property
def index(self):
"""`Index`: Zero-based position within the parent `Dataset <tecplot.data.Dataset>`.
Example usage::
>>> plot.contour(0).variable_index = dataset.variable('S').index
"""
if self._cache:
if not hasattr(self, '_index'):
num = _tecutil.VarGetNumByUniqueID(self.uid)
self._index = tecutil.Index(num - 1)
return self._index
else:
return tecutil.Index(_tecutil.VarGetNumByUniqueID(self.uid) - 1)
@property
def lock_mode(self):
"""`VarLockMode`: Type of lock or `None` (read-only).
Variables may be locked as a result of other operations, typically
through the use of the CFD Analyzer. This read-only property returns
`None` if the variable is not locked, `VarLockMode.ValueChange` if the
variable may not be modified or `VarLockMode.Delete` if the variable
may not be deleted.
This example modifies variable ``s`` only if it is not locked::
>>> variable_s = dataset.variable('s')
>>> if variable_s.lock_mode is None:
... tp.data.operate.execute_equation('{s} = {p}**2')
.. versionadded:: 2019.1
Variable lock mode property requires Tecplot 360 2019 R1 or later.
"""
with self.dataset.frame.activated():
_, mode, _ = _tecutil.VariableIsLocked(self.index + 1)
return mode
[docs]
def minmax(self):
"""Limits of the values stored in this variable across all zones.
:rtype: 2-tuple of `floats <float>`
This always returns `floats <float>` regardless of the underlying data
type::
>>> print(dataset.variable('x').minmax())
(0, 10)
"""
with self.dataset.frame.activated():
success, vmin, vmax = _tecutil.VarGetMinMax(self.index + 1)
if not success:
raise TecplotSystemError()
return vmin, vmax
[docs]
def min(self):
"""Lower bound of the values stored in this variable across all zones.
:rtype: `float`
This always returns a `float` regardless of the underlying data type::
>>> print(dataset.variable('x').min())
0
"""
return self.minmax()[0]
[docs]
def max(self):
"""Upper bound of the values stored in this variable across all zones.
:rtype: `float`
This always returns a `float` regardless of the underlying data type::
>>> print(dataset.variable('x').max())
10
"""
return self.minmax()[1]
@property
def name(self):
"""Returns or sets the name.
:rtype: `string <str>`
.. warning:: **Newlines in string identifiers may affect performance.**
When iterating over many items by name, such as must be done when
fetching an item via pattern matching, PyTecplot will optimize the
search only if there are no newline characters in the searched
items. Iterating over strings that contain newlines will be slower
and therefore, it is best to avoid using newlines in string
identifiers or names of objects such as `Zones <data_access>` or
`Variables <Variable>`.
Example usage::
>>> print(dataset.variable(0).name)
X
"""
res, var_name = _tecutil.VarGetNameByDataSetID(self.dataset.uid,
self.index + 1)
if not res:
raise TecplotSystemError()
return var_name
@name.setter
@tecutil.lock()
def name(self, name):
_tecutil.VarRenameByDataSetID(self.dataset.uid, self.index + 1, name)
@property
def num_zones(self):
"""`int`: Number of `Zones <data_access>` in the parent `Dataset <tecplot.data.Dataset>`.
Example usage, looping over all zones by index::
>>> for zindex in range(dataset.num_zones):
... zone = dataset.zone(zindex)
"""
return self.dataset.num_zones
[docs]
def values(self, pattern):
"""Returns `Array` by index or string pattern.
Parameters:
pattern (`int`, `str` or `Zone <data_access>`): Zero-based index
or `glob-style pattern <fnmatch.fnmatch>` in which case, the
first match is returned, or a `Zone <data_access>` object.
.. note:: **Data operations can make use of Numpy when installed.**
When doing large data transfers into and out of Tecplot using
PyTecplot, it is recommended to install the Python array-processing
module `Numpy <https://scipy.org>`_. PyTecplot will automatically
use this to optimize data transfers which may result in significant
performance gains.
The `Zone.name <OrderedZone.name>` attribute is used to match the
*pattern* to the desired `Array` though this is not necessarily
unique::
>>> ds = frame.dataset
>>> print(ds)
Dataset:
Zones: 'Rectangular zone'
Variables: 'x', 'y', 'z'
>>> x = ds.variable('x')
>>> rectzone = x.values('Rectangular zone')
>>> rectzone == x.values(0)
True
.. warning:: **Zone and variable ordering may change between releases**
Due to possible changes in data loaders or data formats over time,
the ordering of zones and variables may be different between
versions of Tecplot 360. Therefore it is recommended to always
reference zones and variables **by name** instead of by index.
"""
if isinstance(pattern, (str, int)):
zone = self.dataset.zone(pattern)
else:
zone = pattern
return array.Array(zone, self)
