IDA - Revision history

Jpye: /* Internal data structure */

2015-03-23T03:43:54Z

Internal data structure

← Older revision		Revision as of 03:43, 23 March 2015
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	Note that previously '<tt>blsys</tt>' or '<tt>sys</tt>' were used instead of the new preferred variable name '<tt>integ</tt>'.		Note that previously '<tt>blsys</tt>' or '<tt>sys</tt>' were used instead of the new preferred variable name '<tt>integ</tt>'.

	See also [[IDA/~~Analyse~~]] for some more details on the algorithm that ASCEND uses to prepare a model for integration with IDA.		See also [[IDA/Analysis]] for some more details on the algorithm that ASCEND uses to prepare a model for integration with IDA.

	== Example problems ==		== Example problems ==

Jpye: /* Internal data structure */

2015-03-23T03:43:02Z

Internal data structure

← Older revision		Revision as of 03:43, 23 March 2015
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	Note that previously '<tt>blsys</tt>' or '<tt>sys</tt>' were used instead of the new preferred variable name '<tt>integ</tt>'.		Note that previously '<tt>blsys</tt>' or '<tt>sys</tt>' were used instead of the new preferred variable name '<tt>integ</tt>'.

			See also [[IDA/Analyse]] for some more details on the algorithm that ASCEND uses to prepare a model for integration with IDA.

	== Example problems ==		== Example problems ==

Jpye at 21:32, 31 January 2012

2012-01-31T21:32:51Z

← Older revision		Revision as of 21:32, 31 January 2012
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	The general form of problems that IDA can solve is a DAE system,		The general form of problems that IDA can solve is a DAE system,

	<math>		<math>
	\begin{matrix}		\begin{matrix}
	F(t,y,y') = 0 \\		F(t,y,y') = 0 \\

Jpye: /* Internal data structure */

2011-02-03T05:15:35Z

Internal data structure

← Older revision		Revision as of 05:15, 3 February 2011
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	The <tt>slv_get_solvers_var_list(integ->system)</tt> contains all the variables including those that not involved in the system.		The <tt>slv_get_solvers_var_list(integ->system)</tt> contains all the variables including those that not involved in the system.
	The list <tt>integ->y</tt> (called 'blsys->y' in the diagram) contains all the non-derivative variables. The differential variables <tt>~~y_d~~</tt> and the algebraic variables <tt>~~y_a~~</tt> are all mixed up together (so that block partitioning can be used in future). Differential variables can be identified by the fact that <tt>integ->ydot[var_sindex[var]]</tt> will be non-NULL.
			The list <tt>integ->y</tt> (called 'blsys->y' in the diagram) contains all the non-derivative variables. The differential variables <math>\mathbf{y}_d</math> and the algebraic variables <math>\mathbf{y}_a</math> are all mixed up together (so that block partitioning can be used in future). Differential variables can be identified by the fact that <tt>integ->ydot[var_sindex[var]]</tt> will be non-NULL.

	A variable can be identified as a derivative using the <tt>VAR_DERIV</tt> flag (or the <tt>var_deriv(var)</tt> function) or by seeing that its <tt>var_sindex(var)</tt> is greater than <tt>integ->n_y</tt> (it has been moved after all the non-derivative variables).		A variable can be identified as a derivative using the <tt>VAR_DERIV</tt> flag (or the <tt>var_deriv(var)</tt> function) or by seeing that its <tt>var_sindex(var)</tt> is greater than <tt>integ->n_y</tt> (it has been moved after all the non-derivative variables).

Jpye: /* Internal data structure */

2011-02-03T05:13:11Z

Internal data structure

← Older revision		Revision as of 05:13, 3 February 2011
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	The <tt>slv_get_solvers_var_list(integ->system)</tt> contains all the variables including those that not involved in the system.		The <tt>slv_get_solvers_var_list(integ->system)</tt> contains all the variables including those that not involved in the system.
	The list <tt>integ->y</tt> contains all the non-derivative variables. The differential variables <tt>y_d</tt> and the algebraic variables <tt>y_a</tt> are all mixed up together (so that block partitioning can be used in future). Differential variables can be identified by the fact that <tt>integ->ydot[var_sindex[var]]</tt> will be non-NULL.		The list <tt>integ->y</tt> (called 'blsys->y' in the diagram) contains all the non-derivative variables. The differential variables <tt>y_d</tt> and the algebraic variables <tt>y_a</tt> are all mixed up together (so that block partitioning can be used in future). Differential variables can be identified by the fact that <tt>integ->ydot[var_sindex[var]]</tt> will be non-NULL.

	A variable can be identified as a derivative using the <tt>VAR_DERIV</tt> flag (or the <tt>var_deriv(var)</tt> function) or by seeing that its <tt>var_sindex(var)</tt> is greater than <tt>integ->n_y</tt> (it has been moved after all the non-derivative variables).		A variable can be identified as a derivative using the <tt>VAR_DERIV</tt> flag (or the <tt>var_deriv(var)</tt> function) or by seeing that its <tt>var_sindex(var)</tt> is greater than <tt>integ->n_y</tt> (it has been moved after all the non-derivative variables).

Jpye: /* Internal data structure */

2011-02-03T05:12:37Z

Internal data structure

← Older revision		Revision as of 05:12, 3 February 2011
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	[[Image:Diffvars.png\|thumb\|400px\|right]]		[[Image:Diffvars.png\|thumb\|400px\|right]]
	'''Variables'''. The diagram at right shows the internal data structure used to track DAE ~~systems for use by~~ IDA.		'''Variables'''. The diagram at right shows the internal data structure used to track variables in DAE models with IDA.

	The <tt>slv_get_solvers_var_list(integ->system)</tt> contains all the variables including those that not involved in the system.		The <tt>slv_get_solvers_var_list(integ->system)</tt> contains all the variables including those that not involved in the system.

Jpye: /* Internal data structure */

2011-02-03T05:11:56Z

Internal data structure

← Older revision		Revision as of 05:11, 3 February 2011
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	'''Variables'''. The diagram at right shows the internal data structure used to track DAE systems for use by IDA.		'''Variables'''. The diagram at right shows the internal data structure used to track DAE systems for use by IDA.

	The <tt>slv_get_solvers_var_list(~~sys~~-~~>~~system)</tt> contains all the variables including those that not involved in the system.		The <tt>slv_get_solvers_var_list(integ->system)</tt> contains all the variables including those that not involved in the system.
	The list <tt>~~sys~~-~~>~~y</tt> contains all the non-derivative variables. The differential variables <tt>y_d</tt> and the algebraic variables <tt>y_a</tt> are all mixed up together (so that block partitioning can be used in future). Differential variables can be identified by the fact that <tt>~~sys~~-~~>~~ydot[var_sindex[var]]</tt> will be non-NULL.		The list <tt>integ->y</tt> contains all the non-derivative variables. The differential variables <tt>y_d</tt> and the algebraic variables <tt>y_a</tt> are all mixed up together (so that block partitioning can be used in future). Differential variables can be identified by the fact that <tt>integ->ydot[var_sindex[var]]</tt> will be non-NULL.

	A variable can be identified as a derivative using the <tt>VAR_DERIV</tt> flag (or the <tt>var_deriv(var)</tt> function) or by seeing that its <tt>var_sindex(var)</tt> is greater than <tt>~~sys~~-~~>~~n_y</tt> (it has been moved after all the non-derivative variables).		A variable can be identified as a derivative using the <tt>VAR_DERIV</tt> flag (or the <tt>var_deriv(var)</tt> function) or by seeing that its <tt>var_sindex(var)</tt> is greater than <tt>integ->n_y</tt> (it has been moved after all the non-derivative variables).

	To obtain the differential variable corresponding to a derivative variable, use the <tt>integrator_ida_diffindex(var)</tt> function.		To obtain the differential variable corresponding to a derivative variable, use the <tt>integrator_ida_diffindex(var)</tt> function.

	The number of derivatives (and hence number of differential variables) is <tt>~~sys~~-~~>~~n_ydot</tt>. The number of algebraic variables is <tt>~~sys~~-~~>~~n_y - ~~sys~~-~~>~~n_ydot</tt>.		The number of derivatives (and hence number of differential variables) is <tt>integ->n_ydot</tt>. The number of algebraic variables is <tt>integ->n_y - integ->n_ydot</tt>.

	'''Equations''' are also partitioned. Relations are flagged with the <tt>REL_DIFFERENTIAL</tt> flag if they were found to include derivatives. This enables easy iteration through either differential or algebraic equations. And the number of differential equations is stored in <tt>~~sys~~-~~>~~n_diffeqs</tt>.		'''Equations''' are also partitioned. Relations are flagged with the <tt>REL_DIFFERENTIAL</tt> flag if they were found to include derivatives. This enables easy iteration through either differential or algebraic equations. And the number of differential equations is stored in <tt>integ->n_diffeqs</tt>.

			Note that previously '<tt>blsys</tt>' or '<tt>sys</tt>' were used instead of the new preferred variable name '<tt>integ</tt>'.

	== Example problems ==		== Example problems ==

Jpye: /* Internal data structure */

2010-08-02T09:42:15Z

Internal data structure

← Older revision		Revision as of 09:42, 2 August 2010
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	== Internal data structure ==		== Internal data structure ==
	~~<div class="thumb tright"><div class="thumbinner" style="width:402px;">~~[[Image:Diffvars.png~~]] <div class="thumbcaption"><div class="magnify">[[File:Diffvars.png~~\|~~<img src="/skins/common/images/magnify-clip.png" width="15" height="11" alt="" />~~]]~~</div></div></div></div>~~
			[[Image:Diffvars.png\|thumb\|400px\|right]]
	'''Variables'''. The diagram at right shows the internal data structure used to track DAE systems for use by IDA.		'''Variables'''. The diagram at right shows the internal data structure used to track DAE systems for use by IDA.

	The <tt>slv_get_solvers_var_list(sys->system)</tt> contains all the variables including those that not involved in the system.		The <tt>slv_get_solvers_var_list(sys->system)</tt> contains all the variables including those that not involved in the system.
	The list <tt>sys->y</tt> contains all the non-derivative variables. The differential variables <tt>y_d</tt> and the algebraic variables <tt>y_a</tt> are all mixed up together (so that block partitioning can be used in future). Differential variables can be identified by the fact that <tt>sys->ydot[var_sindex[var]]</tt> will be non-NULL.		The list <tt>sys->y</tt> contains all the non-derivative variables. The differential variables <tt>y_d</tt> and the algebraic variables <tt>y_a</tt> are all mixed up together (so that block partitioning can be used in future). Differential variables can be identified by the fact that <tt>sys->ydot[var_sindex[var]]</tt> will be non-NULL.


	A variable can be identified as a derivative using the <tt>VAR_DERIV</tt> flag (or the <tt>var_deriv(var)</tt> function) or by seeing that its <tt>var_sindex(var)</tt> is greater than <tt>sys->n_y</tt> (it has been moved after all the non-derivative variables).		A variable can be identified as a derivative using the <tt>VAR_DERIV</tt> flag (or the <tt>var_deriv(var)</tt> function) or by seeing that its <tt>var_sindex(var)</tt> is greater than <tt>sys->n_y</tt> (it has been moved after all the non-derivative variables).

	To obtain the differential variable corresponding to a derivative variable, use the <tt>integrator_ida_diffindex(var)</tt> function.		To obtain the differential variable corresponding to a derivative variable, use the <tt>integrator_ida_diffindex(var)</tt> function.


	The number of derivatives (and hence number of differential variables) is <tt>sys->n_ydot</tt>. The number of algebraic variables is <tt>sys->n_y - sys->n_ydot</tt>.		The number of derivatives (and hence number of differential variables) is <tt>sys->n_ydot</tt>. The number of algebraic variables is <tt>sys->n_y - sys->n_ydot</tt>.

	'''Equations''' are also partitioned. Relations are flagged with the <tt>REL_DIFFERENTIAL</tt> flag if they were found to include derivatives. This enables easy iteration through either differential or algebraic equations. And the number of differential equations is stored in <tt>sys->n_diffeqs</tt>.		'''Equations''' are also partitioned. Relations are flagged with the <tt>REL_DIFFERENTIAL</tt> flag if they were found to include derivatives. This enables easy iteration through either differential or algebraic equations. And the number of differential equations is stored in <tt>sys->n_diffeqs</tt>.



	== Example problems ==		== Example problems ==

Jpye: /* Solver parameters */

2010-08-02T07:50:28Z

Solver parameters

← Older revision		Revision as of 07:50, 2 August 2010
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	== Solver parameters ==		== Solver parameters ==

	The documentation for these parameters is available via the PyGTK interface (the Integrator dialog) or via the source code for ~~<a href="https://pse.cheme.cmu.edu/svn-view/ascend/code/branches/extfn/base/generic/integrator~~/ida~~.c?view=markup" class="external text" title="https://pse.cheme.cmu.edu/svn-view/ascend/code/branches/extfn/base/generic/integrator~~/ida.c~~?view=markup" rel="nofollow">ida.c</a>~~. This list is still incomplete so the documentation won't be added here just yet.		The documentation for these parameters is available via the PyGTK interface (the Integrator dialog) or via the source code for {{src\|solvers/ida/ida.c}}. This list is still incomplete so the documentation won't be added here just yet.

	<pre>calcic		<pre>calcic

Jpye: /* Linear solvers */

2010-08-02T07:48:53Z

Linear solvers

← Older revision		Revision as of 07:48, 2 August 2010
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	We also plan to add support (as <tt>linsolver='ASCEND'</tt>)for our own sparse direct solver ([[linsolqr]]) but this is not yet complete. Alternatively we might connect another linear solver such as UMFPACK, KLU or SuperLU.		We also plan to add support (as <tt>linsolver='ASCEND'</tt>)for our own sparse direct solver ([[linsolqr]]) but this is not yet complete. Alternatively we might connect another linear solver such as UMFPACK, KLU or SuperLU.

	See also the IDA documentation<~~sup id~~=~~"_ref-ida_0" class="reference"~~>~~<a href="#_note-ida" title="">[1]<~~/a></~~sup~~> for more information.		See also the IDA documentation<ref name=idadoc>IDA User Documentation, https://computation.llnl.gov/casc/sundials/documentation/ida_guide/ida_guide.html</ref> for more information.

	== Index problems ==		== Index problems ==