.. _pathTimeSeries:

Path TimeSeries
^^^^^^^^^^^^^^^

This command is used to construct a Path TimeSeries object. The relationship between load factor and time is input by the user as a series of discrete points in the 2d space (load factor, time). The input points can come from a file or from a list in the script. When the time specified does not match any of the input points, linear interpolation is used between points. There are many ways to specify the load path:

For a load path where the factors are specified in a tcl list with a constant time interval between points:

.. function:: timeSeries Path $tag -dt $dt -values {list_of_values} <-factor $cFactor> <-useLast> <-prependZero> <-startTime $tStart>

For a load path where the factors are specified in a file for a constant time interval between points:

.. function:: timeSeries Path $tag -dt $dt -filePath $filePath <-factor $cFactor> <-useLast> <-prependZero> <-startTime $tStart>

For a load path where the values are specified at non-constant time intervals:

.. function:: timeSeries Path $tag -time {list_of_times} -values {list_of_values} <-factor $cFactor> <-useLast>

For a load path where both time and values are specified in a list included in the command


.. function:: timeSeries Path $tag -fileTime $fileTime -filePath $filePath <-factor $cFactor> <-useLast>

.. csv-table:: 
   :header: "Argument", "Type", "Description"
   :widths: 10, 10, 40

      $tag, |integer|,	   unique tag among TimeSeries objects.
      $filePath, |string|, file containing the load factors values
      $fileTime, |string|,  file containing the time values for corresponding load factors
      $dt, |float|,	   time interval between specified points.
      {list_of_times}	 time values in a tcl list
      {list_of_values}	 load factor values in a tcl list
      $cFactor, |float|, optional, a factor to multiply load factors by (default = 1.0)
      -useLast, |string|, optional, to use last value after the end of the series (default = 0.0)
      -prependZero, |string|, optional, to prepend a zero value to the series of load factors (default = false). 
      $tStart, |float|,  optional, to provide a start time for provided load factors (default = 0.0)
   
   .. notes::

   Linear interpolation between points.

   If the specified time is beyond last point (AND WATCH FOR NUMERICAL ROUNDOFF), 0.0 is returned. Specify -useLast to use the last data point instead of 0.0.

   The transient integration methods in OpenSees assume zero initial conditions. So it is important that any timeSeries that is being used in a transient analysis starts from zero (first data point in the timeSeries = 0.0). To guarantee that this is the case the optional parameter -prependZero can be specified to prepend a zero value to the provided timeSeries.

.. admonition:: EXAMPLE:

   timeSeries Path 1 -dt 0.02 -filePath A-ELC270.AT2 -factor $G
   
   timeSeries Path 2 -time {0.0 0.2 0.4 1.0} -values {0.0 1.0 2.0 0.0}

Code developed by: |fmk|