View Issue Details
|ID||Project||Category||View Status||Date Submitted||Last Update|
|0000549||ascend||integrator||public||2012-04-20 06:53||2012-04-24 08:04|
|Platform||Linux||OS||Ubuntu||OS Version||12.04 LTS|
|Target Version||1.0||Fixed in Version|
|Summary||0000549: IDA can't integrate constants|
|Description||There is an important degenerate case that we can't currently support with the IDA integrator, and possibly other integrators too.|
A model that simply aims to calculate integ(1*t, t) from 0 to 10 fails, because we can't integrate a constant (1).
The problem lies in the integration process, which doesn't add the integral variable unless it's explicitly present in the model equations.
|Steps To Reproduce||In current trunk (changeset 4096) attempt to load the file models/test/ida/integ1.a4c.|
After attempting to start the integration, ASCEND crashes with
ascend/integrator/integrator.c:283 (integrator_set_engine): Setting engine...
ascend/integrator/integrator.c:508 (integrator_analyse): Analysing integration system...
ascend/integrator/integrator.c:448 (integrator_find_indep_var): sys->x already set
ascend/integrator/integrator.c:525 (integrator_analyse): got 0 from integrator_find_indep_var
solvers/ida/idaanalyse.c:521 (integrator_ida_analyse): System contains a total of 0 bnds and 2 rels
solvers/ida/idaanalyse.c:524 (integrator_ida_analyse): Currently 2 rels active
solvers/ida/idaanalyse.c:530 (integrator_ida_analyse): After analysing WHENs, there are 2 rels active
solvers/ida/idaanalyse.c:129 (integrator_ida_check_vars): 'y' has a derivative present, so needs to be included in the system
solvers/ida/idaanalyse.c:130 (integrator_ida_check_vars): That var is active
solvers/ida/idaanalyse.c:214 (integrator_ida_flag_rels): Found 1 differential equations (so 1 algebraic)
PROGRAM FATAL ERROR: solvers/ida/idaanalyse.c:248:integrator_ida_sort_rels_and_vars: Assertion failed: ny1 == integ->n_y
|Tags||No tags attached.|