How to handle multiple time series

An additional feature of SIGSPEC is the ability to handle multiple time series input files at once. This increases the performance of the program significantly, if the time values in all input files are identical.

• The user has to provide only one project directory <project> - just as in SingleFile mode (as described in ``Projects'', p.).
• Parameter specifications in the file <project>.ini are uniquely applied to all time series input files. Thus SIGSPEC expects the same column format for all time series input files and applies the settings specified in the .ini file to all input files.
• Time series files have to be indexed as #multifile#.<project>.dat, where #multifile# represents a six-digit index starting with 000000. Note that strictly ascending indices are required.
• All output files are supplied with the leading index #multifile#. For example, 000012.s000009.000002 denotes the significance specturm the second iteration for time interval number nine in a time-resolved analysis of the 12th file in MultiFile mode.
• The MultiFile mode is activated by the keyword multifile, followed by an integer value. This value is interpreted as the maximum index up to which the calculations shall be performed. This permits a restriction for, e.g., test runs. If the index limit is assigned a negative value, SIGSPEC analyses as many files as available.
• The sampling profile of the file 000000.<project>.dat is always written to a file. For subsequent and consistent time series, the sampling profile is taken from this file, which saves computation time. Only if the new time values are inconsistent with those of the precursor, the profile is re-calculated and stored in a corresponding output file for later use. The keyword profile in the .ini file is ignored in MultiFile mode.

In MultiFile mode, SIGSPEC terminates, if a #multifile# index is reached, for which no time series input file is available.

A further keyword to restrict the MultiFile analysis is mfstart, which permits to specify a MultiFile index to start with (instead of 0).

Example. The two lines

mfstart 4
multifile 16

activate the MultiFile mode for input files from 000004.<project>.dat to 000016.<project>.dat.

The big advantage of the MultiFile mode is that sampling profiles are computed only if necessary. If the time-domain sampling is identical to a previously examined time series, the sampling profile of this time series is used. If the keyword profile is set in the .ini file, a file assign.log is generated. It contains a table of assignments between time series file indices and profile indices.

Example. The line

           000013                           000002}

in the file assign.log means that for 000013.<project>.dat, the profile with index 000002 is used.

Example. The sample project multifile illustrates the simultaneous analysis of multiple time series. The project contains 10 time series files from 000457.multifile.dat to 000467.multifile.dat. However, the files do not represent a complete sequence, since 000466.multifile.dat is missing. The lines

mfstart 457
multifile 467

in the file multifile.ini would force SIGSPEC to process the complete sequence of time series input files. Indeed, the program starts with the file 000457.multifile.dat and proceeds until 000465.multifile.dat. Since the next file, 000466.multifile.dat is missing, it stops its calculations with 000465.multifile.dat and displays a corresponding warning:

Warning: MultiFile_Count 002
         MultiFile limit exceeds number of available
         time series input files, limit re-adjusted to 465.

The keyword profile in the file multifile.ini forces SIGSPEC to generate the following files in the project directory:

000457.profile.dat
000458.profile.dat
000460.profile.dat
000463.profile.dat

The reason why only four profiles are computed for nine time series is found in the file assign.log:

time series input file           profile and spectral window

          000457                           000457
          000458                           000458
          000459                           000457
          000460                           000460
          000461                           000457
          000462                           000457
          000463                           000463
          000464                           000457
          000465                           000457

The contents of this file tell the user that the samplings of all time series files are identical, except for those with indices 000458, 000460 and 000463. In order to speed up the computations, SigSpec generates only one profile for the files with identical sampling and re-uses this profile for all of them. The first file with this sampling is 000457.multifile.dat, and the associated profile is also used for

000459.multifile.dat
000461.multifile.dat
000462.multifile.dat
000464.multifile.dat
000465.multifile.dat

If the keyword win is added to the file multifile.ini, this assignment applies to the files containing the spectral windows as well.