Source code for datamuxer

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from __future__ import (absolute_import, division, print_function,
                        unicode_literals)
import six
from collections import namedtuple, deque
import logging
import pandas as pd
import tzlocal
import numpy as np
from scipy.interpolate import interp1d
import pandas.core.groupby  # to get custom exception


logger = logging.getLogger(__name__)
__all__ = ['DataMuxer', 'dataframe_to_dict']

TZ = str(tzlocal.get_localzone())


[docs]class BinningError(Exception): """ An exception to raise if there are insufficient sampling rules to upsampling or downsample a data column into specified bins. """ pass
[docs]class BadDownsamplerError(Exception): """ An exception to raise if a downsampler produces unexpected output. """ pass
[docs]class ColSpec(namedtuple( 'ColSpec', ['name', 'ndim', 'shape', 'upsample', 'downsample'])): """ Named-tuple sub-class to validate the column specifications for the DataMuxer Parameters ---------- name : hashable ndim : uint Dimensionality of the data stored in the column shape : tuple or None like ndarray.shape, where 0 or None are scalar upsample : {None, 'linear', 'nearest', 'zero', 'slinear', 'quadratic', 'cubic', 'ffill', 'bfill'} None means that each time bin must have at least one value. The names refer to kinds of scipy.interpolator. See documentation link below. downsample : None or a function None if the data cannot be downsampled (reduced). Otherwise, any callable that reduces multiple data points (of whatever dimension) to a single data point. References ---------- http://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.interp1d.html """ # These reflect the 'method' argument of pandas.DataFrame.fillna upsampling_methods = {'None', 'linear', 'nearest', 'zero', 'slinear', 'quadratic', 'cubic', 'ffill', 'bfill'} downsampling_methods = {'None', 'last', 'first', 'median', 'mean', 'sum', 'min', 'max'} _downsample_mapping = {'last': lambda x: x[-1], 'first': lambda x: x[0], # new in np 1.9 'median': lambda x: np.median(x, 0), 'mean': lambda x: np.mean(x, 0), 'sum': lambda x: np.sum(x, 0), 'min': lambda x: np.min(x, 0), 'max': lambda x: np.max(x, 0)} __slots__ = () def __new__(cls, name, ndim, shape, upsample, downsample): # Validations upsample = _validate_upsample(upsample) downsample = _validate_downsample(downsample) if int(ndim) < 0: raise ValueError("ndim must be positive not {}".format(ndim)) if shape is not None: shape = tuple(shape) return super(ColSpec, cls).__new__( cls, name, int(ndim), shape, upsample, downsample)
def _validate_upsample(input): # TODO The upsampling method could be any callable. if input is None or input == 'None': return 'None' if not (input in ColSpec.upsampling_methods): raise ValueError("{} is not a valid upsampling method. It " "must be one of {}".format( input, ColSpec.upsampling_methods)) return input.lower() def _validate_downsample(input): # TODO The downsampling methods could have string aliases like 'mean'. if (input is not None) and (not (callable(input) or input in ColSpec.downsampling_methods)): raise ValueError("The downsampling method must be a callable, None, " "or one of {}.".format(ColSpec.downsampling_methods)) if input is None: return 'None' return input
[docs]class DataMuxer(object): """ This class provides a wrapper layer of signals and slots around a pandas DataFrame to make plugging stuff in for live view easier. The data collection/event model being used is all measurements (that is values that come off of the hardware) are time stamped to ring time. The language being used through out is that of pandas data frames. The data model is that of a sparse table keyed on time stamps which is 'densified' on demand by propagating measurements forwards. Not all measurements (ex images) can be filled. This behavior is controlled by the `col_info` tuple. Parameters ---------- events : list list of Events (any object with the expected attributes will do) """ class Planner(object): def __init__(self, dm): self.dm = dm def determine_upsample(self, interpolation=None, use_cols=None): "Resolve (and if necessary validate) upsampling rules." if interpolation is None: interpolation = dict() if use_cols is None: use_cols = self.dm.columns rules = dict() for name in use_cols: col_info = self.dm.col_info[name] rule = _validate_upsample( interpolation.get(name, col_info.upsample)) rule = _normalize_string_none(rule) if (rule is not None) and (col_info.ndim > 0): raise NotImplementedError( "Only scalar data can be upsampled. " "The {0}-dimensional source {1} was given the " "upsampling rule {2}.".format( col_info.ndim, name, rule)) rules[name] = rule return rules def determine_downsample(self, agg=None, use_cols=None): "Resolve (and if necessary validate) sampling rules." if agg is None: agg = dict() if use_cols is None: use_cols = self.dm.columns rules = dict() for name in use_cols: col_info = self.dm.col_info[name] rule = _validate_downsample(agg.get(name, col_info.downsample)) rule = _normalize_string_none(rule) rules[name] = rule return rules def bin_by_edges(self, bin_edges, bin_anchors, interpolation=None, agg=None, use_cols=None): """Explain operation of DataMuxer.bin_by_edges Parameters ---------- bin_edges : list list of two-element items like [(t1, t2), (t3, t4), ...] bin_anchors : list These are time points where interpolated values will be evaluated. Bin centers are usually a good choice. interpolation : dict, optional Override the default interpolation (upsampling) behavior of any data source by passing a dictionary of source names mapped onto one of the following interpolation methods. {None, 'linear', 'nearest', 'zero', 'slinear', 'quadratic', 'cubic', 'ffill', 'bfill'} None means that each time bin must have at least one value. See scipy.interpolator for more on the other methods. agg : dict, optional Override the default reduction (downsampling) behavior of any data source by passing a dictionary of source names mapped onto any callable that reduces multiple data points (of whatever dimension) to a single data point. use_cols : list, optional List of columns to include in binning; use all columns by default. Returns ------- df : pandas.DataFrame table giving upsample and downsample rules for each data column and indicating whether those rules are applicable References ---------- http://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.interp1d.html """ bin_anchors, binning = self.dm._bin_by_edges(bin_anchors, bin_edges) # TODO Cache the grouping for reuse by resample. grouped = self.dm._dataframe.groupby(binning) counts = grouped.count() df = pd.DataFrame.from_dict(_is_resampling_applicable(counts)) df['upsample'] = self.determine_upsample(interpolation, use_cols) df['downsample'] = self.determine_downsample(agg, use_cols) return df def bin_on(self, source_name, interpolation=None, agg=None, use_cols=None): """Explain operation of DataMuxer.bin_on. Parameters ---------- source_name : string interpolation : dict, optional Override the default interpolation (upsampling) behavior of any data source by passing a dictionary of source names mapped onto one of the following interpolation methods. {None, 'linear', 'nearest', 'zero', 'slinear', 'quadratic', 'cubic'} None means that each time bin must have at least one value. See scipy.interpolator for more on the other methods. agg : dict, optional Override the default reduction (downsampling) behavior of any data source by passing a dictionary of source names mapped onto any callable that reduces multiple data points (of whatever dimension) to a single data point. use_cols : list, optional List of columns to include in binning; use all columns by default. Returns ------- df : pandas.DataFrame table giving upsample and downsample rules for each data column and indicating whether those rules are applicable References ---------- http://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.interp1d.html """ centers, bin_edges = self.dm._bin_on(source_name) bin_anchors, binning = self.dm._bin_by_edges(centers, bin_edges) # TODO Cache the grouping for reuse by resample. grouped = self.dm._dataframe.groupby(binning) counts = grouped.count() df = pd.DataFrame.from_dict(_is_resampling_applicable(counts)) df['upsample'] = self.determine_upsample(interpolation, use_cols) df['downsample'] = self.determine_downsample(agg, use_cols) return df default_upsample = None default_downsample = None
[docs] def __init__(self): self.sources = {} self.col_info = {} self.col_info['time'] = ColSpec('time', 0, [], 'linear', 'mean') self._data = deque() self._time = deque() self._timestamps = deque() self._timestamps_as_data = set() self._known_events = set() self._known_descriptors = set() self._stale = True self.plan = self.Planner(self) self.convert_times = True self._reference_time = None
@property def reference_time(self): return self._reference_time @reference_time.setter def reference_time(self, val): self._reference_time = pd.Timestamp(val, unit='s') @property def columns(self): "The columns of DataFrames returned by methods that return DataFrames." return set(self.sources) | self._time_columns @property def _time_columns(self): ts_names = [name + '_timestamp' for name in self._timestamps_as_data] return {'time'} | set(ts_names) @classmethod
[docs] def from_events(cls, events, verbose=False): """ Create a DataMuxer from a list of Events. Parameters ---------- events : list list of Events (any objects with the expected attributes will do) """ instance = cls() instance.append_events(events, verbose) return instance
def append_events(self, events, verbose=False): """Add a list of events to the DataMuxer. Parameters ---------- events : list list of Events (any objects with the expected attributes will do) """ for idx, event in enumerate(events): if verbose and idx % 25 == 0: print('loading event %s' % idx), self.append_event(event) def append_event(self, event): """Add an event to the DataMuxer. Parameters ---------- event : Event Event Document or any object with the expected attributes Returns ------- is_new : bool True if event was added, False is it has already been added """ if event.uid in self._known_events: return False self._known_events.add(event.uid) self._stale = True if event.descriptor.uid not in self._known_descriptors: self._process_new_descriptor(event.descriptor) # Both scalar and nonscalar data will get stored in the DataFrame. # This may be optimized later, but it might not actually help much. self._data.append( {name: data for name, data in six.iteritems(event.data)}) self._timestamps.append( {name: ts for name, ts in six.iteritems(event.timestamps)}) self._time.append(event.time) return True def _process_new_descriptor(self, descriptor): "Build a ColSpec and update state." for name, description in six.iteritems(descriptor.data_keys): # If we already have this source name, the unique source # identifiers must match. Ambiguous names are not allowed. if name in self.sources: if self.sources[name] != description['source']: raise ValueError("In a previously loaded descriptor, " "'{0}' refers to {1} but in Event " "Descriptor {2} it refers to {3}.".format( name, self.sources[name], descriptor.uid, description['source'])) if name == 'time': # We can argue later about how best to handle this corner # case, but anything is better than silently mislabeling # data. raise ValueError("The name 'time' is reserved and cannot " "be used as an alias.") # If it is a new name, determine a ColSpec. else: self.sources[name] = description['source'] if 'external' in description and 'shape' in description: shape = description['shape'] ndim = len(shape) else: # External data can be scalar. Nonscalar data must # have a specified shape. Thus, if no shape is given, # assume scalar. shape = None ndim = 0 upsample = self.default_upsample if ndim > 0: upsample = None col_info = ColSpec(name, ndim, shape, upsample, self.default_downsample) # defaults # TODO Look up source-specific default in a config file # or some other source of reference data. self.col_info[name] = col_info self._known_descriptors.add(descriptor.uid) @property def _dataframe(self): "See also to_sparse_dataframe, the public version of this." # Rebuild the DataFrame if more data has been added. if self._stale: df = pd.DataFrame(list(self._data)) df['time'] = list(self._time) if self._timestamps_as_data: # Only build this if we need it. # TODO: We shouldn't have to build # the whole thing, but there is already a lot of trickiness # here so we'll worry about optimization later. timestamps = pd.DataFrame(list(self._timestamps)) for source_name in self._timestamps_as_data: col_name = _timestamp_col_name(source_name) df[col_name] = timestamps[source_name] logger.debug("Including %s timestamps as data", source_name) self._df = df.sort('time').reset_index(drop=True) self._stale = False return self._df
[docs] def to_sparse_dataframe(self, include_all_timestamps=False): """Obtain all measurements in a DataFrame, one row per Event time. Parameters ---------- include_all_timestamps : bool The result will always contain a 'time' column but, by default, not timestamps for individual data sources like 'motor_timestamp'. Set this to True to export timestamp columns for each data column Returns ------- df : pandas.DataFrame """ if include_all_timestamps: raise NotImplementedError("TODO") result = self._dataframe.copy() for col_name in self._time_columns: result[col_name] = self._maybe_convert_times(result[col_name]) return result
def _maybe_convert_times(self, data): if self.convert_times: t = pd.to_datetime(data, unit='s', utc=True).dt.tz_localize(TZ) if self.reference_time is None: return t else: return t - self.reference_time return data # no-op def include_timestamp_data(self, source_name): """Add the exact timing of a data source as a data column. Parameters ---------- source_name : string one of the source names in DataMuxer.sources """ # self._timestamps_as_data is a set of sources who timestamps # should be treated as data in the _dataframe method above. self._timestamps_as_data.add(source_name) name = _timestamp_col_name(source_name) self.col_info[name] = ColSpec(name, 0, None, None, np.mean) self._stale = True def remove_timestamp_data(self, source_name): """Remove the exact timing of a data source from the data columns. Parameters ---------- source_name : string one of the source names in DataMuxer.sources """ self._timestamps_as_data.remove(source_name) # Do not force a rebuilt (i.e., self._stale). Just remove it here. del self._df[_timestamp_col_name(source_name)]
[docs] def bin_on(self, source_name, interpolation=None, agg=None, use_cols=None): """ Return data resampled to align with the data from a particular source. Parameters ---------- source_name : string interpolation : dict, optional Override the default interpolation (upsampling) behavior of any data source by passing a dictionary of source names mapped onto one of the following interpolation methods. {None, 'linear', 'nearest', 'zero', 'slinear', 'quadratic', 'cubic'} None means that each time bin must have at least one value. See scipy.interpolator for more on the other methods. agg : dict, optional Override the default reduction (downsampling) behavior of any data source by passing a dictionary of source names mapped onto any callable that reduces multiple data points (of whatever dimension) to a single data point. use_cols : list, optional List of columns to include in binning; use all columns by default. Returns ------- resampled_df : pandas.DataFrame References ---------- http://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.interp1d.html """ centers, bin_edges = self._bin_on(source_name) return self.bin_by_edges(bin_edges, bin_anchors=centers, interpolation=interpolation, agg=agg, use_cols=use_cols)
def _bin_on(self, source_name): "Compute bin edges spaced around centers defined by source_name points." col = self._dataframe[source_name] centers = self._dataframe['time'].reindex_like(col.dropna()).values # [2, 4, 6] -> [-inf, 3, 5, inf] bin_edges = np.mean([centers[1:], centers[:-1]], 0) # [-inf, 3, 5, inf] -> [(-inf, 3), (3, 5), (5, inf)] bin_edges = [-np.inf] + list(np.repeat(bin_edges, 2)) + [np.inf] bin_edges = np.reshape(bin_edges, (-1, 2)) return centers, bin_edges
[docs] def bin_by_edges(self, bin_edges, bin_anchors, interpolation=None, agg=None, use_cols=None): """ Return data resampled into bins with the specified edges. Parameters ---------- bin_edges : list list of two-element items like [(t1, t2), (t3, t4), ...] bin_anchors : list These are time points where interpolated values will be evaluated. Bin centers are usually a good choice. interpolation : dict, optional Override the default interpolation (upsampling) behavior of any data source by passing a dictionary of source names mapped onto one of the following interpolation methods. {None, 'linear', 'nearest', 'zero', 'slinear', 'quadratic', 'cubic'} None means that each time bin must have at least one value. See scipy.interpolator for more on the other methods. agg : dict, optional Override the default reduction (downsampling) behavior of any data source by passing a dictionary of source names mapped onto any callable that reduces multiple data points (of whatever dimension) to a single data point. use_cols : list, optional List of columns to include in binning; use all columns by default. Returns ------- resampled_df : pandas.DataFrame References ---------- http://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.interp1d.html """ bin_anchors, binning = self._bin_by_edges(bin_anchors, bin_edges) return self.resample(bin_anchors, binning, interpolation, agg, use_cols=use_cols)
def _bin_by_edges(self, bin_anchors, bin_edges): "Compute bin assignment and, if needed, bin_anchors." time = self._dataframe['time'].values # Get edges into 1D array[L, R, L, R, ...] edges_as_pairs = np.reshape(bin_edges, (-1, 2)) all_edges = np.ravel(edges_as_pairs) if not np.all(np.diff(all_edges) >= 0): raise ValueError("Illegal binning: the left edge must be less " "than the right edge.") # Sort out where the array each time would be inserted. binning = np.searchsorted(all_edges, time).astype(float) # Times that would get inserted at even positions are between bins. # Mark them binning[binning % 2 == 0] = np.nan binning //= 2 # Make bin number sequential, not odds only. if bin_anchors is None: bin_anchors = np.mean(edges_as_pairs, axis=1) # bin centers else: if len(bin_anchors) != len(bin_edges): raise ValueError("There are {0} bin_anchors but {1} pairs of " "bin_edges. These must match.".format( len(bin_anchors), len(bin_edges))) return bin_anchors, binning def resample(self, bin_anchors, binning, interpolation=None, agg=None, verify_integrity=True, use_cols=None): """ Return data resampled into bins with the specified edges. Parameters ---------- bin_anchors : list These are time points where interpolated values will be evaluated. Bin centers are usually a good choice. bin_anchors : list Bin assignment. Example: [1, 1, 2, 2, 3, 3] puts six data points into three bins with two points each. interpolation : dict, optional Override the default interpolation (upsampling) behavior of any data source by passing a dictionary of source names mapped onto one of the following interpolation methods. {None, 'linear', 'nearest', 'zero', 'slinear', 'quadratic', 'cubic'} None means that each time bin must have at least one value. See scipy.interpolator for more on the other methods. agg : dict, optional Override the default reduction (downsampling) behavior of any data source by passing a dictionary of source names mapped onto any callable that reduces multiple data points (of whatever dimension) to a single data point. verify_integrity : bool, optional For a cost in performance, verify that the downsampling function produces data of the expected shape. True by default. use_cols : list, optional List of columns to include in binning; use all columns by default. Returns ------- resampled_df : pandas.DataFrame References ---------- http://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.interp1d.html """ if use_cols is None: use_cols = self.columns plan = self.Planner(self) upsampling_rules = plan.determine_upsample(interpolation, use_cols) downsampling_rules = plan.determine_downsample(agg, use_cols) grouped = self._dataframe.groupby(binning) first_point = grouped.first() counts = grouped.count() resampling_requirements = _is_resampling_applicable(counts) index = np.arange(len(bin_anchors)) result = {} # dict of DataFrames, to become one MultiIndexed DataFrame for name in use_cols: upsample = upsampling_rules[name] downsample = downsampling_rules[name] upsampling_possible = resampling_requirements['upsampling_possible'][name] downsampling_needed = resampling_requirements['downsampling_needed'][name] result[name] = pd.DataFrame(index=index) # Put the first (maybe only) value into a Series. # We will overwrite as needed below. result[name]['val'] = pd.Series(data=first_point[name]) # Short-circuit if we are done. if not (upsampling_possible or downsampling_needed): logger.debug("%s has exactly one data point per bin", name) continue result[name]['count'] = counts[name] # If any bin has no data, use the upsampling rule to interpolate # at the center of the empty bins. If there is no rule, simply # leave some bins empty. Do not raise an error. if upsampling_possible and (upsample is not None): if upsample in ('ffill', 'bfill'): result[name]['val'].fillna(method=upsample, inplace=True) else: dense_col = self._dataframe[name].dropna() y = dense_col.values x = self._dataframe['time'].reindex_like(dense_col).values interpolator = interp1d(x, y, kind=upsample) # Outside the limits of the data, the interpolator will # fail. Leave any such entires empty. is_safe = ((bin_anchors > np.min(x)) & (bin_anchors < np.max(x))) safe_times = bin_anchors[is_safe] safe_bins = index[is_safe] interp_points = pd.Series(interpolator(safe_times), index=safe_bins) logger.debug("Interpolating to fill %d of %d " "empty bins in %s", len(safe_bins), (counts[name] == 0).sum(), name) result[name]['val'].fillna(interp_points, inplace=True) # Short-circuit if we are done. if not downsampling_needed: logger.debug("%s has at most one data point per bin", name) continue # Multi-valued bins must be downsampled (reduced). If there is no # rule for downsampling, we have no recourse: we must raise. if (downsample is None): raise BinningError("The specified binning puts multiple " "'{0}' measurements in at least one bin, " "and there is no rule for downsampling " "(i.e., reducing) it.".format(name)) if verify_integrity and callable(downsample): downsample = _build_verified_downsample( downsample, self.col_info[name].shape) g = grouped[name] # for brevity if self.col_info[name].ndim == 0: logger.debug("The scalar column %s must be downsampled.", name) # For scalars, pandas knows what to do. downsampled = g.agg(downsample) std_series = g.std() max_series = g.max() min_series = g.min() else: # For nonscalars, we are abusing groupby and must go to a # a little more trouble to guarantee success. logger.debug("The nonscalar column %s must be downsampled.", name) if not callable(downsample): # Do this lookup here so that strings can be passed # in the call to resample. downsample = ColSpec._downsample_mapping[downsample] downsampled = g.apply(lambda x: downsample(np.asarray(x.dropna()))) std_series = g.apply(lambda x: np.std(np.asarray(x.dropna()), 0)) max_series = g.apply(lambda x: np.max(np.asarray(x.dropna()), 0)) min_series = g.apply(lambda x: np.min(np.asarray(x.dropna()), 0)) # This (counts[name] > 1) is redundant, but there is no clean way to # pass it here without refactoring. Not a huge cost. result[name]['val'].where(~(counts[name] > 1), downsampled, inplace=True) result[name]['std'] = std_series result[name]['max'] = max_series result[name]['min'] = min_series result = pd.concat(result, axis=1) # one MultiIndexed DataFrame result.index.name = 'bin' # Convert time timestamp or timedelta, depending on the state of # self.convert_times and self.reference_time. for col_name in self._time_columns: if isinstance(result[col_name], pd.DataFrame): subcols = result[col_name].columns for subcol in subcols & {'max', 'min', 'val'}: result[(col_name, subcol)] = self._maybe_convert_times( result[(col_name, subcol)]) for subcol in subcols & {'std'}: result[(col_name, subcol)] = pd.to_timedelta( result[(col_name, subcol)], unit='s') else: result[col_name] = self._maybe_convert_times( result[col_name]) return result def __getitem__(self, source_name): if source_name not in list(self.col_info.keys()) + ['time']: raise KeyError("No data from a source called '{0}' has been " "added.".format(source_name)) # Unlike output from binning functions, this is indexed # on time. result = self._dataframe[source_name].dropna() result.index = self._dataframe['time'].reindex_like(result) return result def __getattr__(self, attr): # Developer beware: if any properties raise an AttributeError, # this will mask it. Comment this magic method to debug properties. if attr in self.col_info.keys(): return self[attr] else: raise AttributeError("DataMuxer has no attribute {0} and no " "data source named '{0}'".format(attr)) @property def ncols(self): """ The number of columns that the DataMuxer contains """ return len(self.col_info) @property def col_info_by_ndim(self): """Dictionary mapping dimensionality (ndim) onto a list of ColSpecs""" result = {} for name, col_spec in six.iteritems(self.col_info): try: result[col_spec.ndim] except KeyError: result[col_spec.ndim] = [] result[col_spec.ndim].append(col_spec) return result
[docs]def dataframe_to_dict(df): """ Turn a DataFrame into a dict of lists. Parameters ---------- df : DataFrame Returns ------- index : ndarray The index of the data frame data : dict Dictionary keyed on column name of the column. The value is one of (ndarray, list, pd.Series) """ dict_of_lists = {col: df[col].to_list() for col in df.columns} return df.index.values, dict_of_lists
def _build_verified_downsample(downsample, expected_shape): # Ensure two things: # 1. The downsampling function shouldn't touch bins with only one point. # 2. The result of downsample should have the right shape. def _downsample(data): if len(data) == 1: return data downsampled = downsample(data) if (expected_shape is None or expected_shape == 0): if not np.isscalar(downsampled): raise BadDownsamplerError("The 'agg' (downsampling) function " "for {0} is expected to produce " "a scalar from the data in each " "bin.".format(downsampled)) elif downsampled.shape != expected_shape: raise BadDownsamplerError("An 'agg' (downsampling) function " "returns data shaped {0} but the " "shape {1} is expected.".format( downsampled.shape, expected_shape)) return downsampled return _downsample def _timestamp_col_name(source_name): return '{0}_timestamp'.format(source_name) def _normalize_string_none(val): "Replay passes 'None' to mean None." try: lowercase_val = val.lower() except AttributeError: return val if lowercase_val == 'none': return None else: return val def _is_resampling_applicable(counts): has_no_points = counts == 0 has_multiple_points = counts > 1 upsampling_possible = has_no_points.any() downsampling_needed = has_multiple_points.any() result = {} result['upsampling_possible'] = upsampling_possible.to_dict() result['downsampling_needed'] = downsampling_needed.to_dict() return result