id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
4990	Should we make IDA the default ODE mode solver?	Francesco Casella	Andreas Heuermann	"The IDA solver has been implemented as an alternative to DASSL for quite some time. IDA is in fact DASSL's successor: it implements the same basic algorithm, but it is written natively in C and, contrary to DASSL, it is  actively maintained as a part of the SUNDIALS suite, so it is in general expected to give better performance than the old DASSL. In principle, once we have IDA implemented I see no reason to keep DASSL as the default option. In fact, I have some test cases where DASSL fails and IDA works just fine.

Unfortunately, 99% of the users will just use the default solver and, in case of simulation issues, won't probably think of solving them by simply switching to IDA.

So, the question is: should we make ida the default solver for ode mode simulations, in place of dassl?

I guess in order to answer this question we need to run the whole testsuite with ida as a default solver and look for regressions and improvements.

Currently, we have  Hudson tasks running the whole testsuite with ida and daeMode (https://libraries.openmodelica.org/branches/daemode/ and https://libraries.openmodelica.org/branches/newInst-daemode/), but I don't think we should make daeMode the default solver option. 

@sjoelund.se, could you set up a task to be run on demand such as https://libraries.openmodelica.org/branches/daemode/, but only with -s=ida as default simflag and no daeMode?

I could then analyze the results, so we can take an informed decision. In fact, it could be that ida has few recessions, or possibly none, and a lot of improvements compared to dassl already. On the other hand, if there are issues left we could try to solve them, and/or to give suggestions to the end users when should they perfer IDA over DASSL.
"	enhancement	assigned	high		Run-time				Martin Sjölund Adrian Pop