The cacheGetFilenames User Command

All user commands have the form:

ldasJob { -name {} -password {} -email {} } { userCmd -opt1 {} ... }

Which is in the format of a Tcl command, ldasJob, with two required arguments:

1. A Tcl list of user information consisting of username, password, and e-mail address. All fields must be filled or the command will be rejected.
   Client software which would like to receive responses from the LDAS system on a port instead of through email can provide a hostname:port combination as the email argument. A further feature of this method is that the hostname can be replaced with the magic key !host!, and the LDAS system will use the IP address it finds by doing a peername lookup on the connected socket.
2. A user command in the form of a Tcl list, for which there exists a "meta" macro file which can be expanded into Tcl code which can then be evaluated by the LDAS system.
   An argument need not be provided for every option. Some options have default values and these are described below as appropriate.
   Meta macros consist of a prototype declaration of the arguments for the given user command, and a template describing the calling order of API specific blocks of Tcl code which are concatenated into a larger block comprising the complete request, which can then be distributed by the assistant manager for interpretation by the low level API's.
   These API specific blocks are maintained as API specific macro files consisting of immediately interpretable Tcl code.

• cacheGetFilenames

• cacheGetFilenames

  Returns list of absolute paths to frame files.

  An exception is generated if the filename provided (or the calcualted filename when no explicit filename is provided) does not exist or is not readable due to permission problems.

  An e-mail with a URL pointing to the location of the results file is sent (-returnprotocol http or ftp is supported for retrieval of the file by mailcap/mime-types).

  Calling convention (all on a single line):

  ldasJob   { -name   "username"   -password   "********"   -email   "user@foobar.edu"}   {cacheGetFilenames   -ifos   IFO Abbrev   -types   frame type   -times   GPS times   -channels   list of channel names   -framequery   alternate syntax   }

  Option Descriptions:

  -ifos:     Valid IFO

  Optional: defaults to best guess based on other options
  The argument of the -ifos option is a list of interferometer (ifo) abbreviations as used in the file naming convention and corresponding to the file name prefix of the frame files created from that interferometer. This option is used together with the -times and -types options.

  The -ifos option is being deprecated in favor of the -channels option, q.v.

  -types:     {}

  Optional: defaults to R
  The argument to the -types option is a list of frame types as used in the frame file naming convention. This corresponds to the second field of the frame file name. This option is used together with the -times and -ifos options to specify a frame file with the desired list of channels.

  -times:     Valid GPS time

  Optional: defaults to most recent file in directory
  The argument to the -time option is a GPS time for which frame data exists. This option is used together with the -frametype and -interferometer options to specify a frame file with the desired list of channels.

  -channels:     list of channel names

  
  The listing of channels is the preferred way of getting interferometer specifications into this command, and any included channel spec will override any explicit ifos spec.

  Alternate Syntax:

  The -framequery syntax is available as an aid to developing proper -framequery options for dataPipeline and other "real" user commands. The frame filenames returned will be identical to the ones made sent to the frame API in a dataPipeline user command using the same option.

  -framequery:     {R H {} 666666666-666666669 Adc(1,2,5-15)}

  The -framequery option is REQUIRED for getFrameData, getFrameElements, and concatFrameData user commands, but is OPTIONAL for conditionData, dataStandAlone, and dataPipeline user commands.
  The -framequery argument is a complex list of frame API query atoms. The query atoms consist of unique identifying strings (which are not case sensitive) with indices or channel names grouped in parentheses. The query atom strings consist of the unique parts of the accessor function names from the frame API c++ code. (See: frameAPI.so)

  The -framequery syntax now supports a complex associative format which allows the simultaneous retrieval of unrelated data elements from multiple sources.
  In the simplest case, a single frame repository containing frames from more than one instrument can be queried to retrieve a common time range from each specified interferometer:

  • -framequery { {} {H L} {} 600000000-600000007 Adc(0)}
    This query will return the data for Adc 0 from both Hanford and Livingston over the gps time period 600000000 to 600000007.
  • -framequery { { {} H {} 600000000-600000007 Adc(H2:LSC-AS_Q)}{ {} L {} 600000000-600000007 Adc(L1:LSC-AS_Q)}}
    This query will return the data from both Hanford and Livingston over the gps time range 600000000 to 600000007 for the H2 and L1 so called gravitational wave channels.

  The five fields of the complex framequery are:

  1. frame type
  2. interferometers
  3. frames
  4. times
  5. channels (and/or structures for which accessors exist)
  Any field which is not used must contain a pair of braces "{}" as a placeholder so that all sublists of the -framequery always consist of five elements.

  The framequery option supports the slicing syntax Adc(channel!start!range[type]!) or Proc(channel!start!range[type]!):
  The "slicing" syntax allows a subset of an Adc or Proc data channel to be obtained. Slicing is performed by appending two floating-point numeric arguments, the start and range, to the channel specification (the fifth field of the framequery), delimited by !'s. The start is the absolute starting position of the slice along the x-axis of the channel, and the range is the extent of the slice.
  Valid [type] specifications are TIME, FREQ, and TIMEFREQ. When no type specifier is given, time is assumed, and this may generate errors if frequency series data is found.
  The units of the both numbers are taken from the unitX field for the specified channel in the frame file when the data is operated on by an another API. This is usually seconds for time-series data and Hertz for frequency-series data.

  Note that the extent of the x-axis of a channel is not related to the GPS time of the frame. The first value on the x-axis is given by the startX field of the channel, and the extent is given by the number of samples in the channel times the dx field of the channel. While startX may have any value, it is usually 0, although there are cases where it could be negative, such as for a 2-sided power spectrum.

  The sliced data will contain all samples whose x-coordinate satisfy start <= x < start + range. An error will be generated if the start of the slice is less than startX, or if the slice extends past the end of the channel.

  Examples of slicing:

  Suppose we are accessing a channel from frame H-R-600000000.gwf:

  Adc(H2:LSC_AS-Q!0.3!0.4TIME!)

  The ! syntax determines a start-time and range within the channel (since startX is zero for time-series data, the start-time may be interpreted as an offset from the GPS start-time of the framequery). The syntax requires that the channel name be followed by a !, followed immediately by a valid time offset into the data array for the channel, followed by another !, followed immediately by a range, followed by a final !.

  This example will return a 0.4 second long slice of the channel data from GPS time 600000000.300000000 through 600000000.700000000.
  The ILWD object containing this data slice will have the correct calculated start-time and times-span for this slice of data, as well as the correct number of data points in the data array.

  Suppose we have a Proc frame with a Proc structure containing frequency spectrum data with Hertz as the x-axis units. We can request a specific frequency band by specifying a start-frequency and a frequency range:

  Proc(0!1024!1024FREQ!)

  This will return a Proc structure containing the data at all frequency bins greater than or equal to 1024 Hz and less than 2048 Hz, that is, all frequency data in the semi-open interval [0, 1024) Hz. Any metadata associated with the original object will be passed though unmodified.

  NOTE on frequency slicing:
  The directive Adc(CAL-CAV_GAIN!0!2048.0001FREQ!) is interpreted by LDAS as all frequencies >= 0 and < 2048.0001.
  Note the strict inequality for the upper limit. The frequency of a bin is determined by:

       f_k = startX + k*df, k = 0, 1, ..., N-1
  

  so you just need to make sure your request is consistent with this scheme. The reason some users are adding 0.0001 is becuase they have f-sequences that have a bin that they want at EXACTLY 2048 Hz (say), so they need to specify an upper limit above this ie. the upper limit must be strictly greater than 2048 and less than or equal to 2048 + df Hz. If adding 0.0001 works for you fine, but that's obviously not the only choice. This might seem a strange convention but the reason it's chosen is:
  1. to be consistent with the way we specify time intervals, which are also given as semi-open intervals.

  2. so that it's easy to pull out sub-sequences of frequency series and/or concatenate them in a non-overlapping way ie:
     [ ... ) [ ... ) [ ... )

  The framequery option support for downsampling syntax Adc(channel!resample!q!) or Proc(channel!resample!q!):
  Suppose we are asking for gravity wave channel data over an hour, but want to downsample the data by a factor of 8 before it is sent to the dataconditioning API:

  Adc(H2:LSC_AS-Q!resample!8!)

  In the case of resampling, the first field after the channel name contains the literal string "resample", and the second field contains the downsampling factor q. (see the resampling algorithm documentation.)

  It is intended that resampling be applied after data has been time sliced based on the time range part of the framequery option.
  As of the 0.2.0 release of LDAS, this has been imperfectly implemented, and it is important that users wishing to make effective use of the resampling syntax provide feedback to the developers via the problem tracking system:

  LDAS Problem Tracking System

  Note that the only supported resampling factors are 2, 4, 8, and 16. The -framequery option by-the-numbers:

  The first element of the complex -framequery option is a list of the type of the frames which should be retrieved. The type refers to the frame attribute referenced by the second field in the proposed frame spec. This filed defaults internall to R, or "Raw".
  Another example of a frame type would be mT, or "Minute Trend".
  separate output container will be created for each interferometer specified.

  The second element of the complex -framequery option is a list of the interferomenters which produced the data that is wanted. A separate output container will be created for each interferometer specified.

  The third element of the complex -framequery option is a Tcl list of frame file names or URL's.
  This option is generally only used when a single specific input frame file (or a single file from, say each of two interferometers) is needed, and is provided primarily for the application of data conditioning or pipelining of test data in the form of frame files.
  This option will become the mecahnism for the reading of calibration or other process data from frame files at a later time.

  The fourth element of the -framequery option, times, is a Tcl list of GPS timestamps and ranges. The times argument must have the form a-b where a and b are valid GPS times in whole numbers of seconds. Due to historical precedent, this range should be interpreted as a request for data including the second starting at a until the end of the second starting at b, thus the actual interval of time being requested is [a, b+1). For example, -times 666666666-666666681 represents the equivalent of specifying the names of 16 1-second frame files, and represents the 17 seconds of data from time 666666666 up to but not including 666666682.
  The syntax supports a gap filling flag: 666666666-666666681:allow_gaps which the LDAS system recognises as an indication that it should allow missing frame files, and to account for them in the data conditioning stage of the user command by filling in missing data points as specified by the fillgaps action in the algorithms option.
  Note that the -allowgaps option to the dataPipeline user command overrides all the syntactical subtleties implied here and will cause a single data segment spanning all specified time ranges to be created.

  Example:

  -framequery { {} H {} {666666666-666666669:allow_gaps 666667660-666667665} full(0)}

  Will, with the -allowgaps option specified, ultimately result in a single frame of 1000 seconds duration.

  Note that the times element of the -framequery option returns the data spanning the range of time from the top of the starting second to the bottom of the ending second.

  The fifth element of the -framequery option supports a shorthand notation for frame structure accessor methods exposed to the Tcl layer. The most commonly used methods are the Adc() and Proc() accessors, which retrieves Adc (time serialised data) or Proc (time, freq, or time-freq domain) channel structures from frames.The argument to this accessor method can be an integer (referring to the ith channel) OR the specific name of a channel:

       Adc(12)
       Adc(H2:LSC-AS_Q)
  

  An argument of "full()" as an item in the framequery option list will result in either a copy of the frame if the return format is specified as "frame", a full text dump of the frame if the return format is specified as "ilwd", and a full XML dump if the format is specified as LIGO_LW.

  Example Commands (all equivalent):

  cacheGetFilenames -ifos H -types R -times 600000000-600000123
  
  cacheGetFilenames -channels H2:LSC-AS_Q -types R -times 600000000-600000123
  
  cacheGetFilenames -framequery { R H {} 600000000-600000123 Adc(H2:LSC-AS_Q) }
  

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