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MuonPairingAsymmetry v1¶

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Summary ¶

Apply a pairing asymmetry calculation between two detector groups from Muon data.

Properties ¶

Name	Direction	Type	Default	Description
OutputWorkspace	Output	MatrixWorkspace	Mandatory	The workspace which will hold the results of the asymmetry calculation.
PairName	Input	string		The name of the pair. Must contain at least one alphanumeric character.
Alpha	Input	number	1	Alpha parameter used in the asymmetry calculation.
SpecifyGroupsManually	Input	boolean	False	Specify the pair of groups manually
InputWorkspace1	Input	Workspace		Input workspace containing data from grouped detectors.
InputWorkspace2	Input	Workspace		Input workspace containing data from grouped detectors.
InputWorkspace	Input	WorkspaceGroup		Input workspace containing data from detectors which are to be grouped.
Group1	Input	int list	1	The grouping of detectors, comma separated list of detector IDs or hyphenated ranges of IDs.
Group2	Input	int list	2	The grouping of detectors, comma separated list of detector IDs or hyphenated ranges of IDs.
SummedPeriods	Input	int list	1	A list of periods to sum in multiperiod data.
SubtractedPeriods	Input	int list		A list of periods to subtract in multiperiod data.

When interacting with the Muon Analysis interface, operations such as detector grouping, group and pair asymmetry are performed on data. This algorithm performs a “pair asymmetry” operation, in other words it takes two groups (from MuonGroupingCounts v1 for example) and calculates the asymmetry between them using the common formula from AsymmetryCalc v1.

This algorithm is part of a set of four; with MuonPreProcess v1 being run first; and the output being fed into this one. Alternatively, the groups may be calculated by using MuonPreProcess v1 followed by MuonGroupingCounts v1 and fed into this algorithm by switching off SpecifyGroupsManually. This allows the replication of the workflow used by the muon analysis interface to produce group data.

Analysis ¶

A Pair in this context refers to a pair of groups. A workspace has one or more spectra contained within it; each spectra has a unique detector ID. Assuming the y-values represent counts; a detector group is a sum over a given set of detectors.

With a pair, one may define an asymmetry operation as in AsymmetryCalc v1;

\[A = \frac{F-\alpha B}{F+\alpha B},\]

where \(F\) and \(B\) are the forward and backwards groups and alpha is the balance parameter.

The pair must be given a name via PairName which can consist of letters, numbers and underscores.

Valid names : “pair”, “pair2”, “pair_2”, “1234”
Invalid names : “”, “pair!”, “pair “

The pair name does not affect the data; however the name is used in the muon interface when automatically generating workspace names from group data.

Additionally, a value for alpha must be supplied, and which must be non-negative.

There are two options for supplying the group data :

If SpecifyGroupsManually is checked, then the detector ID’s that define the two groups must be given (they must be unique); and an InputWorkspace supplied. This workspace must be a WorkspaceGroup to match the output of MuonPreProcess v1, where the group contains one MatrixWorkspace for each period.
If SpecifyGroupsManually is not checked, then two workspaces must be supplied which represent the two groups via InputWorkspace1 and InputWorkspace2. These may be MatrixWorkspace*s (in the case of single period data); or *WorkspaceGroup*s (in the case of multi period data, the two groups must contain the same number of workspaces). Any *MatrixWorkspace must only contain one spectra (the group counts).

Multi period data ¶

Both single and multi period data are supported by the algorithm.

The SummedPeriods and SubtractedPeriods inputs are used to control the way that periods are combined. so for example;

SummedPeriods = 1,2
SubtractedPeriods = 3,4

would combine periods in the combination \((1+2)-(3+4)\).

Usage ¶

Example - Using MuonPreProcess and Specifying Groups Manually for Single Period Data

# Create a workspaces with four spectra
dataX = [0, 1, 2, 3, 4, 5] * 4
dataY = [10, 20, 30, 20, 10] + \
        [20, 30, 40, 30, 20] + \
        [30, 40, 50, 40, 30] + \
        [40, 50, 60, 50, 40]
input_workspace = CreateWorkspace(dataX, dataY, NSpec=4)
for i in range(4):
    # set detector IDs to be 1,2,3,4
    # these do not have to be the same as the spectrum numbers
    # (the spectrum number are 0,1,2,3 in this case)
    input_workspace.getSpectrum(i).setDetectorID(i + 1)

pre_processed_workspace = MuonPreProcess(InputWorkspace=input_workspace)

output_workspace = MuonPairingAsymmetry(InputWorkspace=pre_processed_workspace,
                                                  PairName="myPair",
                                                  Alpha=1.0,
                                                  SpecifyGroupsManually=True,
                                                  Group1=[1, 2],
                                                  Group2=[3, 4])

print("X values are : {}".format([round(float(i), 3) for i in output_workspace.readX(0)]))
print("Y values are : {}".format([round(float(i), 3) for i in output_workspace.readY(0)]))

Output:

X values are : [0.5, 1.5, 2.5, 3.5, 4.5]
Y values are : [-0.4, -0.286, -0.222, -0.286, -0.4]

Example - Using MuonPreProcess and Specifying Groups Manually for Multi Period Data

# Create a workspaces with four spectra
dataX = [0, 1, 2, 3, 4, 5] * 4
dataY = [10, 20, 30, 20, 10] + \
        [20, 30, 40, 30, 20] + \
        [30, 40, 50, 40, 30] + \
        [40, 50, 60, 50, 40]

input_workspace = CreateWorkspace(dataX, dataY, NSpec=4)
input_workspace_1 = CreateWorkspace(dataX, dataY, NSpec=4)
for i in range(4):
    # set detector IDs to be 1,2,3,4
    # these do not have to be the same as the spectrum numbers
    # (the spectrum number are 0,1,2,3 in this case)
    input_workspace.getSpectrum(i).setDetectorID(i + 1)
    input_workspace_1.getSpectrum(i).setDetectorID(i + 1)

# Create multi period data
multi_period_data = GroupWorkspaces(input_workspace)
multi_period_data.addWorkspace(input_workspace_1)

pre_processed_workspace = MuonPreProcess(InputWorkspace=multi_period_data)

output_workspace = MuonPairingAsymmetry(InputWorkspace=pre_processed_workspace,
                                                  PairName="myPair",
                                                  Alpha=1.0,
                                                  SpecifyGroupsManually=True,
                                                  Group1=[1, 2],
                                                  Group2=[3, 4],
                                                  SummedPeriods=[1, 2])

print("X values are : {}".format([round(float(i), 3) for i in output_workspace.readX(0)]))
print("Y values are : {}".format([round(float(i), 3) for i in output_workspace.readY(0)]))

Output:

X values are : [0.5, 1.5, 2.5, 3.5, 4.5]
Y values are : [-0.4, -0.286, -0.222, -0.286, -0.4]

Example - Using MuonPreProcess, MuonGroupingCounts for Single Period Data

# Create a workspaces with four spectra
dataX = [0, 1, 2, 3, 4, 5] * 4
dataY = [10, 20, 30, 20, 10] + \
        [20, 30, 40, 30, 20] + \
        [30, 40, 50, 40, 30] + \
        [40, 50, 60, 50, 40]
input_workspace = CreateWorkspace(dataX, dataY, NSpec=4)
for i in range(4):
    # set detector IDs to be 1,2,3,4
    # these do not have to be the same as the spectrum numbers
    # (the spectrum number are 0,1,2,3 in this case)
    input_workspace.getSpectrum(i).setDetectorID(i + 1)

pre_processed_workspace = MuonPreProcess(InputWorkspace=input_workspace)
group_workspace_1 = MuonGroupingCounts(InputWorkspace=pre_processed_workspace,
                                                 GroupName="fwd",
                                                 Grouping=[1, 2])
group_workspace_2 = MuonGroupingCounts(InputWorkspace=pre_processed_workspace,
                                                 GroupName="bwd",
                                                 Grouping=[3, 4])

output_workspace = MuonPairingAsymmetry(InputWorkspace=pre_processed_workspace,
                                                  PairName="myPair",
                                                  Alpha=1.0,
                                                  SpecifyGroupsManually=False,
                                                  InputWorkspace1=group_workspace_1,
                                                  InputWorkspace2=group_workspace_2)

print("X values are : {}".format([round(float(i), 3) for i in output_workspace.readX(0)]))
print("Y values are : {}".format([round(float(i), 3) for i in output_workspace.readY(0)]))

Output:

X values are : [0.5, 1.5, 2.5, 3.5, 4.5]
Y values are : [-0.4, -0.286, -0.222, -0.286, -0.4]

Categories: AlgorithmIndex | Muon\DataHandling

Source ¶

C++ header: MuonPairingAsymmetry.h

C++ source: MuonPairingAsymmetry.cpp

MuonPairingAsymmetry v1¶

Summary ¶

See Also ¶

Properties ¶

Description ¶

Analysis ¶

Multi period data ¶

Usage ¶

Source ¶