[BLDG-SIM] VisualSPARK 2.0 RELEASED

[Frederick Winkelmann]

VisualSPARK 2.0 RELEASED!

Version 2.0 of the VisualSPARK environment for simulation
of advanced building energy systems has just been released.
For more information on VisualSPARK, a complete list of new features,
or to download the program free of charge, please go to
http://SimulationResearch.lbl.gov > VisualSPARK.

A few of the new features are:

SPARSE LINEAR SOLUTION METHOD
This method reduces calculation time by orders of magnitude on
large simulation problems that have a sparse Jacobian matrix.

MULTI-VALUED INVERSE FUNCTIONS
In SPARK 1 all inverse functions were single-valued, i.e., the
inverse returned only one value. SPARK 2 allows inverse functions to
return two or more values simultaneously.

XML PROBLEM DESCRIPTION
The problem topology is now described by an XML file. This allows
having a compiler- and linker-free SPARK as long as all atomic
classes are compiled and built as dynamic libraries.

IMPROVED SOLUTION METHODS
o Integrated newest release of UMFPACK for the sparse linear solver.
o Added perturbed Newton solution method.
o Added keys in the Preference file for safety factors used in
convergence
  test(for Prediction/Iteration stage and Break/Normal unknown
variables).
o Added a key in the Preference file to specifiy the minimum number
  of iterations when solving the strong components.
o Added variable scale for all problem variables.

NEW RUNTIME CONTROL PARAMETERS
o Added the following keys in the .run file:
- InitialConsistentCalculation to indicate whether or not to calculate
  consistent values at the initial time by solving for the
time-derivatives
  of the dynamic variables using the specified boundary conditions.
- InitialTimeStep to specify the value of the initial time step.
- VariableTimeStep to indicate whether or not to vary the time step
during
  the simulation.
- MinTimeStep to specifiy the smallest allowed time step.
- MaxTimeStep to specifiy the largest allowed time step.

NEW DRIVER API
o Now supports both static and dynamic build operations in the driver
  function.
o The runtime problem loader now supports explicit linking from dynamic
  libraries.

READ URL MECHANISM
This is a generalized way of specifying where and how input values
are obtained at runtime. With this mechanism SPARK can now read;
o EnergyPlus, DOE-2 and TMY weather files
o DOE-2 schedules
o Algebraic expressions
o ASCII formatted files

VARIABLE TIME STEPPING
Added an Euler integration method with variable time step to reduce
calculation time and to control local truncation error.

INTERFACE IMPROVEMENTS

o Tree-view of problem showing objects associated with the problem.
o Right-clicking on a project name now pops up a menu with choice
  to edit the problem file or show the tree structure of the problem.
o Right-clicking on a class name pops up a menu from which you may
choose
  to edit the class file or show the tree structure of the class.
o Checkbox to allow variable time step and inputs for mininum and
maximum
  time step.
o Wallclock entries to choose date and time for run (e.g. for reading
  weather file data.
o Comparative plots of related problems: you can show same variables
from
  multiple runs of problems on same graph.
o New tab showing Structure and Defaults:
  - Structure: shows problem structure as a tree; you can browse
inverses,
    parameters, input variables and unknowns.
  - Defaults: shows default values for solution methods, max iterations,
etc.
o Component tab shows component structures as trees, where you can
browse
  unknowns and objects, including their inverses, targets and callbacks.

-------------------

SPARK was developed by the Simulation Research Group of Lawrence
Berkeley National Laboratory and by Ayres Sowell Associates, with
support from the Assistant Secretary for Energy Efficiency and
Renewable Energy, Office of Building Technology Programs of the U.S.
Department of Energy, program manager Dru Crawley.


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