4.78 sddsslopes

• description: sddsslopes makes straight line fits of column data of the input file with respect to a selected column used as independent variable. The output file contains a one-row data set of slopes and intercepts for each data set of the input file. Errors on the slope and intercept may be calculated as an option.
• examples: The file corrector.sdds below contains beam position monitors (bpms) readbacks as a function of corrector setting. The defined columns are CorrectorSetpoint and the series bpm1, bpm2, etc. The bpm response to the corrector setpoints are calculated with the use of sddsslopes:

  sddsslopes corrector.sdds corrector.slopes -independentVariable=CorrectorSetpoint -columns=’bpm*’

  where all columns that match with the wildcard expression bpm* is selected for fitting.

• synopsis:

  sddsslopes [-pipe=[input][,output]] inputFile outputFile -independentVariable=parameterName [-range=lower,upper] [-columns=listOfNames] [-excludeColumns=listOfNames] [-sigma[=generate]] [-residual=file] [-ascii] [-verbose]

• files: The input file contains the tabular data for fitting. Multiple data sets are processed one at a time. For optional error processing, additional columns of sigma values associated with the data to be fitted must be present. These sigma column must be named nameSigma or Sigmaname, the former one being searched first.

  The output file contains a one-row data set for each data set in the input file. The columns defined have names such as nameSlope, and nameIntercept where name is the name of the fitted data. If only one file is specified, then the input file is overwritten by the output. A string column called IndenpendentVariable is defined containing the name of the indepedent variable.

• switches:
  • -pipe[=input][,output] — The standard SDDS Toolkit pipe option.
  • -independentVariable=parametername — name of independent variable (default is the first valid column).
  • -range=lower,upper — The range of the independent variable where the fit is calculated. By default, all data points are used.
  • -columns=listOfNames — columns to be individually paired with independentVariable for straight line fitting.
  • -excludeColumns=listOfNames — columns to exclude from fitting.
  • -sigma[=generate] — calculates errors by interpreting column names nameSigma or Sigmaname as sigma of column name. If these columns don’t exist then the program generates a common sigma from the residual of a first fit, and refits with these sigmas. If option -sigma=generate is given, then sigmas are generated from the residual of a first fit for all columns, irrespective of the presence of columns nameSigma or Sigmaname.
  • -residual=file — Specifies an output file into which the residual of the fits are written. The column names in the residual file are the same as they appear in the input file.
  • -ascii — make output file in ascii mode (binary is the default).
  • -verbose — prints some output to stderr.
• author: L. Emery ANL