id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
3325	Symbolic Jacobian is not generated for systems with one state	Lennart Ochel	Lennart Ochel	"Just a simple example:
{{{#!mo
model foo
  Real x1(start=1.0, fixed=true);
equation
  der(x1) = 0;
end foo;
}}}

The LOG_SOLVER dump indicates that there is something wrong with the generated symbolic jacobian:
{{{
LOG_SOLVER        | info    | sparse structure of jacobian A [size: 0x0]
}}}

In fact, there is no symbolic Jacobian generated. But if the model get extended by a second state, then the Jacobian is generated as expected:
{{{#!mo
model foo
  Real x1(start=1.0, fixed=true);
  Real x2(start=1.0, fixed=true);
equation
  der(x1) = 0;
  der(x2) = 0;
end foo;
}}}

{{{
LOG_SOLVER        | info    | sparse structure of jacobian A [size: 2x2]
|                 | |       | | 0 nonzero elements
|                 | |       | | transposed sparse structure (rows: states)
|                 | |       | | |
|                 | |       | | |
}}}
"	defect	closed	critical	1.9.4	Backend	trunk	fixed