3.11

SaveGSS v1

../_images/SaveGSS-v1_dlg.png

SaveGSS dialog.

Summary

Saves a focused data set into a three column GSAS format.

Properties

Name Direction Type Default Description
InputWorkspace Input MatrixWorkspace Mandatory The input workspace, which must be in time-of-flight
Filename Input string Mandatory The filename to use for the saved data
SplitFiles Input boolean True Whether to save each spectrum into a separate file (‘true’) or not (‘false’). Note that this is a string, not a boolean property.
Append Input boolean True If true and Filename already exists, append, else overwrite
Bank Input number 1 The bank number to include in the file header for the first spectrum, i.e., the starting bank number. This will increment for each spectrum or group member.
Format Input string RALF GSAS format to save as. Allowed values: [‘RALF’, ‘SLOG’]
DataFormat Input string FXYE Saves RALF data as either FXYE or alternative format. Allowed values: [‘FXYE’, ‘ALT’]
MultiplyByBinWidth Input boolean True Multiply the intensity (Y) by the bin width; default TRUE.
ExtendedHeader Input boolean False Add information to the header about iparm file and normalization
UseSpectrumNumberAsBankID Input boolean False If true, then each bank’s bank ID is equal to the spectrum number; otherwise, the continuous bank IDs are applied.

Description

Saves a focused data set into a three column GSAS format containing X_i, Y_i*step, and E_I*step. Exclusively for the crystallography package GSAS and data needs to be in time-of-flight. For data where the focusing routine has generated several spectra (for example, multi-bank instruments), the option is provided for saving all spectra into a single file, separated by headers, or into several files that will be named “workspaceName_”+workspace_index_number.

From the GSAS manual a description of the format options:

  • If BINTYP is ‘SLOG’ then the neutron TOF data was collected in constant ∆T/T steps. BCOEF(1) is the initial TOF in μsec, and BCOEF(3) is the value of ∆T/T used in the data collection. BCOEF(2) is a maximum TOF for the data set. BCOEF(4) is zero and ignored.
  • If BINTYP equals ‘RALF’ then the data was collected at one of the TOF neutron diffractometers at the ISIS Facility, Rutherford-Appleton Laboratory. The width of the time bins is constant for a section of the data at small values of TOF and then varies (irregularly) in pseudoconstant ∆T/T steps. In this case BCOEF(1) is the starting TOF in μsec*32, BCOEF(2) is the width of the first step in μsec*32, BCOEF(3) is the start of the log scaled step portion of the data in μsec*32 and BCOEF(4) is the resolution to be used in approximating the size of each step beyond BCOEF(3).

The format is limited to saving 99 spectra in total. Trying to save more will generate an error.

Usage

Example - a basic example using SaveGSS.

import os
# Create a workspace to save
ws = CreateSampleWorkspace(OutputWorkspace="SaveGSSWorkspace")
ws = ExtractSingleSpectrum(ws, WorkspaceIndex=0)

# Save to the users home directory
file_name = "myworkspace.ascii"
path = os.path.join(os.path.expanduser("~"), file_name)
SaveGSS(ws, path)

# Does the file exist
path = os.path.join(os.path.expanduser("~"), file_name)
print os.path.isfile(path)

Output:

True

Example - an example using SaveGSS with additonal options.

import os

ws = CreateSampleWorkspace(OutputWorkspace="SaveGSSWorkspace")
# GSAS file cannot have more than 99 entries
ws = CropWorkspace(ws, StartWorkspaceIndex=0, EndworkspaceIndex=98)

# Save out GSAS file
file_name = "myworkspace.ascii"
path = os.path.join(os.path.expanduser("~"), file_name)
SaveGSS(ws, path, SplitFiles=False, ExtendedHeader=True, UseSpectrumNumberAsBankID=True)

print os.path.isfile(path)

Output:

True

Categories: Algorithms | Diffraction\DataHandling | DataHandling\Text

Source

C++ source: SaveGSS.cpp

C++ header: SaveGSS.h