return invalid-problem instead of just infeasible if inconsistent bou…

…nds/sides

- reason is that for infeasible problems, we usually call finalize and
  provide statistics, but this does not happen (and seems difficult to
  add) if TNLPAdapter throws an exception in GetSpaces()
- also we do not apply tolerances to this kind of infeasibility
- we may, however, change the definition of the problem that Ipopt can
  handle to require that bounds/sides are not contradicting

doc/main.dox

@@ -36,14 +36,15 @@ form \anchor NLP
 \f}
 where \f$x \in \mathbb{R}^n\f$ are the optimization variables (possibly with
 lower and upper bounds, \f$x^L\in(\mathbb{R}\cup\{-\infty\})^n\f$ and
-\f$x^U\in(\mathbb{R}\cup\{+\infty\})^n\f$),
+\f$x^U\in(\mathbb{R}\cup\{+\infty\})^n\f$) with \f$x^L \leq x^U\f$,
 \f$f:\mathbb{R}^n \to \mathbb{R}\f$ is the objective function, and
 \f$g:\mathbb{R}^n \to \mathbb{R}^m\f$ are the general nonlinear
 constraints. The functions \f$f(x)\f$ and \f$g(x)\f$ can be linear or nonlinear
 and convex or non-convex (but should be twice continuously
-differentiable). The constraints, \f$g(x)\f$, have lower and upper bounds,
+differentiable). The constraint functions, \f$g(x)\f$, have lower and upper bounds,
 \f$g^L\in(\mathbb{R}\cup\{-\infty\})^m\f$ and
-\f$g^U\in(\mathbb{R}\cup\{+\infty\})^m\f$. Note that equality constraints of
+\f$g^U\in(\mathbb{R}\cup\{+\infty\})^m\f$ with \f$g^L \leq g^U\f$.
+Note that equality constraints of
 the form \f$g_i(x)=\bar g_i\f$ can be specified by setting
 \f$g^L_{i}=g^U_{i}=\bar g_i\f$.
 

doc/output.dox

@@ -216,10 +216,12 @@ output message to the console, and a brief description.
 
 - `Invalid_Problem_Definition`:
 
-   Console Message: (no console message, this is a return code for the C and Fortran interfaces only.)
-
-   This indicates that there was an exception of some sort when
-   building the \ref IpoptProblem structure in the C or Fortran interface.
+   Console Message: `EXIT: Problem has inconsistent variable bounds or constraint sides.`
+
+   This indicates that either there was an exception of some sort when
+   building the \ref IpoptProblem structure in the C or Fortran interface
+   or bounds specified for variables or constraints were inconsistent
+   (lower bound larger than upper bound, left-hand-side larger than right-hand-side).
    Likely there is an error in your model or the main routine.
 
 - `Unrecoverable_Exception`:

src/Interfaces/IpIpoptApplication.cpp

@@ -1135,9 +1135,8 @@ ApplicationReturnStatus IpoptApplication::call_optimize()
    {
       exc.ReportException(*jnlst_, J_MOREDETAILED);
       jnlst_->Printf(J_SUMMARY, J_MAIN, "\nEXIT: Problem has inconsistent variable bounds or constraint sides.\n");
-      retValue = Infeasible_Problem_Detected;
+      retValue = Invalid_Problem_Definition;
       status = LOCAL_INFEASIBILITY;
-      skip_finalize_solution_call = true; /* has already been called by TNLPAdapter (and we don't know the correct primal solution) */
    }
    catch( IpoptException& exc )
    {