Nonlinear equation system of size 1

[Lennart Ochel]

Nonlinear equation system of size 1 do not show up in the backend as nonlinear equation.

model A
  Real x;
equation
  sin(x) = time;
end A;

Currently, this equation get solved using a nonlinear solver. However, the backenddaeinfo-dump shows the following:

Notification: Model statistics after passing the front-end and creating the data structures used by the back-end:
 * Number of equations: 1
 * Number of variables: 1
Notification: Model statistics after passing the back-end for initialization:
 * Number of independent subsystems: 1
 * Number of states: 0 ('+d=stateselection' for list of states)
 * Number of discrete variables: 0 ('+d=discreteinfo' for list of discrete vars)
 * Number of discrete states: 0 ('+d=discreteinfo' for list of discrete states)
 * Top-level inputs: 0
Notification: Strong component statistics for initialization (1):
 * Single equations (assignments): 1
 * Array equations: 0
 * Algorithm blocks: 0
 * Record equations: 0
 * When equations: 0
 * If-equations: 0
 * Equation systems (linear and non-linear blocks): 0
 * Torn equation systems: 0
 * Mixed (continuous/discrete) equation systems: 0
Notification: Model statistics after passing the back-end for simulation:
 * Number of independent subsystems: 1
 * Number of states: 0 ('+d=stateselection' for list of states)
 * Number of discrete variables: 0 ('+d=discreteinfo' for list of discrete vars)
 * Number of discrete states: 0 ('+d=discreteinfo' for list of discrete states)
 * Top-level inputs: 0
Notification: Strong component statistics for simulation (1):
 * Single equations (assignments): 1
 * Array equations: 0
 * Algorithm blocks: 0
 * Record equations: 0
 * When equations: 0
 * If-equations: 0
 * Equation systems (linear and non-linear blocks): 0
 * Torn equation systems: 0
 * Mixed (continuous/discrete) equation systems: 0

[Vitalij Ruge]

fixed in r24150 for simulation,
fixed in r24157 for initialization.

as test case we have already the print in Tearing9...

[Vitalij Ruge]

I will partial revert r24150,
there some side effect, if we manipulate(too soon) single equation, which are in the initialization equation system of size bigger 1.

[Vitalij Ruge]

side effect = e.g. other tearing

[Vitalij Ruge]

fixed with ​PR549