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GeneralisedSecondDifference v1

GeneralisedSecondDifference dialog.

Summary

Computes the generalised second difference of a spectrum or several spectra.

Properties

Name	Direction	Type	Default	Description
InputWorkspace	Input	MatrixWorkspace	Mandatory	Name of the input workspace
OutputWorkspace	Output	MatrixWorkspace	Mandatory	The name of the workspace to be created as the output of the algorithm
M	Input	number	0	The number of points for averaging, i.e. summing will be done in the range [y(i-m),y(i+m)]
Z	Input	number	0	The number of iteration steps in the averaging procedure
WorkspaceIndexMin	Input	number	0	Lower bound of the spectrum range (default 0)
WorkspaceIndexMax	Input	number	0	Upper bound of the spectrum range (default workspace max)

Description

Compute the generalised second difference of a spectrum or several spectra based on the method described by M.A. Mariscotti., Nuclear Instruments and Methods 50, 309 (1967). Given a spectrum with value yi (0<=i<n), the generalised second difference corresponds to the second difference curve, smoothed by averaging each point in the interval [-m,+m], and applying this procedure z times.

Usage

Example - Use on a single peak

# Create Workspace with peak around x=15.0
ws = CreateSampleWorkspace(BankPixelWidth=1, Xmax=30, BinWidth=1)

# Apply algorithm.
wsD = GeneralisedSecondDifference(ws,M=2,Z=2)

# Show values around the peak
print("{:.2f}, {:.2f}, {:.2f}, {:.2f}, {:.2f}".format(wsD.readY(0)[8], wsD.readY(0)[9], wsD.readY(0)[10], wsD.readY(0)[11], wsD.readY(0)[12]))
print("Peak at {}".format(wsD.readX(0)[10]))

Output:

-0.34, -7.21, -20.00, -7.21, -0.34
Peak at 15.0

Categories: AlgorithmIndex | Arithmetic

Source

C++ header: GeneralisedSecondDifference.h

C++ source: GeneralisedSecondDifference.cpp