= Description =
To simulate chemical or biological process in Diana the Initial Value Problem should be solved at first. A guess for initial conditions can be set in model file. [[BR]] Standard {{{ IDACalcIC() }}} method of Sundials package can calculate consistent initial conditions for differential algebraic equations systems, [[BR]]whose state vector can be separated into a dynamic part and algebraic part. If this is not possible {{{IDACalcIC()}}} generates the exception
{{{
   ECapeUnknown in IDASolver (Diana) startIntegrator, IDACalcIC failed
}}}

'''''ICSolver''''' can calculate initial conditions for systems without any conversions of the equations.[[BR]]
[attachment:ICSolver.pdf "Mathematical and programming explanations of ICSolver implementation (pdf)"]
= Example =

[attachment:AdsColumn.mdl "Adsorption column model"] contains the equations system[[BR]]
[attachment:AdsColumn_error.py "Python script with calling standard IDACalcIC() method"] generates the exception[[BR]]
[attachment:AdsColumn.py "Python script with using ICSolver and nonzero output verbosity level"] shows the initial state vector and message

{{{
   ICSolver: Consistent initial conditions have been found
}}}

== Additional information ==

{{{ eso.GetAllVariables() }}} returns state vector values of equation set object[[BR]]
{{{ eso.GetAllResiduals() }}} returns vector of right hand side values of equations system with current values of state vector[[BR]]
''Note: With correct state vector initial values all residuals of equation set object should be equal to zeros''

== Additional examples ==

 * Hafke reactor[[BR]]
   [attachment:HafkeReactor.py "script"] [attachment:HafkeReactor.tar "script + model + results"]

 * Cstr model[[BR]]
   [attachment:Cstr.py "script"] [attachment:Cstr.tar "script + model + results"]

 * MATLAB example[[BR]]
   [attachment:matlab.tar "files"]