e04tbc is a part of the NAG optimization modelling suite and allows you to
enable various components of the existing model which were previously
disabled by
e04tcc.
e04tcc and
e04tbc form a pair of functions which allow you to temporarily disable and then reenable parts of a model. This is particularly useful when a sequence of similar problems needs to be solved, to identify how a particular constraint or variable affects the solution, or to switch between previously defined constraints which are somewhat related to each other.
e04tbc may be used to reenable a component of the model previously disabled by a call to
e04tcc. The components to be reenabled are identified by supplying the same value of
comp and
idx as used in the call to
e04tcc when they were disabled. All newly created components of the model are enabled. Calling this function on enabled components is not an error but has no effect.
See
Section 4.1 in the
E04 Chapter Introduction for more details about the NAG optimization modelling suite.
None.

1:
$\mathbf{handle}$ – void *
Input

On entry: the handle to the problem. It needs to be initialized (e.g., by
e04rac) and
must not be changed between calls to the NAG optimization modelling suite.

2:
$\mathbf{comp}$ – const char *
Input

On entry: the type of the component of the model to be enabled.
comp is case insensitive.
 ${\mathbf{comp}}=''X''$, $''VAR''$ or $''VARIABLE''$
 Decision variables $x$.
 ${\mathbf{comp}}=''LC''$ or $''LINEAR\; CONSTRAINT''$
 Linear constraints (see e04rjc).
 ${\mathbf{comp}}=''QC''$ or $''QUADRATIC\; CONSTRAINT''$
 Quadratic constraints (see e04rsc and e04rtc).
 ${\mathbf{comp}}=''NLC''$ or $''NONLINEAR\; CONSTRAINT''$
 Nonlinear constraints (see e04rkc).
 ${\mathbf{comp}}=''CN''$ or $''CONE''$
 Quadratic or rotated quadratic cones (see e04rbc).
 ${\mathbf{comp}}=''MI''$ or $''MATRIX\; INEQUALITY''$
 Matrix inequality constraints (see e04rnc).
 ${\mathbf{comp}}=''NLS''$ or $''RESIDUAL''$
 Nonlinear residuals ${r}_{j}\left(x\right)$ in the nonlinear least squares objective function (see e04rmc).
Constraint:
${\mathbf{comp}}=''X''$, $''VAR''$, $''VARIABLE''$, $''LC''$, $''LINEAR\; CONSTRAINT''$, $''QC''$, $''QUADRATIC\; CONSTRAINT''$, $''NLC''$, $''NONLINEAR\; CONSTRAINT''$, $''CN''$, $''CONE''$, $''MI''$, $''MATRIX\; INEQUALITY''$, $''NLS''$ or $''RESIDUAL''$.

3:
$\mathbf{lidx}$ – Integer
Input

On entry: the number of elements in the index set.
Constraint:
${\mathbf{lidx}}\ge 1$.

4:
$\mathbf{idx}\left[{\mathbf{lidx}}\right]$ – const Integer
Input

On entry: the index set of components
comp to be enabled. The elements may be supplied in any order.
Constraint:
$1\le {\mathbf{idx}}\left[\mathit{i}1\right]\le M$, for $\mathit{i}=1,2,\dots ,{\mathbf{lidx}}$, where $M$ is the total number of the given components (e.g., decision variables) in the model.

5:
$\mathbf{fail}$ – NagError *
Input/Output

The NAG error argument (see
Section 7 in the Introduction to the NAG Library CL Interface).
 NE_ALLOC_FAIL

Dynamic memory allocation failed.
See
Section 3.1.2 in the Introduction to the NAG Library CL Interface for further information.
 NE_BAD_PARAM

On entry, argument $\u27e8\mathit{\text{value}}\u27e9$ had an illegal value.
 NE_DELETED

On entry, ${\mathbf{comp}}=\u27e8\mathit{\text{value}}\u27e9$ and ${\mathbf{idx}}\left[i1\right]=\u27e8\mathit{\text{value}}\u27e9$.
This component has been deleted.
This error can only occur when trying to enable a cone constraint that has been deleted by setting its size to $0$ with e04rbc.
 NE_HANDLE

The supplied
handle does not define a valid handle to the data structure for the NAG optimization modelling suite. It has not been properly initialized or it has been corrupted.
 NE_INDICES

On entry, ${\mathbf{comp}}=\u27e8\mathit{\text{value}}\u27e9$, $i=\u27e8\mathit{\text{value}}\u27e9$, ${\mathbf{idx}}\left[i1\right]=\u27e8\mathit{\text{value}}\u27e9$ and $M=\u27e8\mathit{\text{value}}\u27e9$.
Constraint: $1\le {\mathbf{idx}}\left[i1\right]\le M$.
 NE_INT

On entry, ${\mathbf{lidx}}=\u27e8\mathit{\text{value}}\u27e9$.
Constraint: ${\mathbf{lidx}}\ge 1$.
 NE_INTERNAL_ERROR

An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please contact
NAG for assistance.
See
Section 7.5 in the Introduction to the NAG Library CL Interface for further information.
 NE_NO_LICENCE

Your licence key may have expired or may not have been installed correctly.
See
Section 8 in the Introduction to the NAG Library CL Interface for further information.
 NE_PHASE

The problem cannot be modified right now, the solver is running.
 NE_STR_UNKNOWN

On entry, ${\mathbf{comp}}=\u27e8\mathit{\text{value}}\u27e9$.
Constraint: ${\mathbf{comp}}=''X''$, $''LC''$, $''QC''$, $''NLC''$, $''CN''$, $''MI''$ or $''NLS''$.
Not applicable.
Please consult the
X06 Chapter Introduction for information on how to control and interrogate the OpenMP environment used within this function. Please also consult the
Users' Note for your implementation for any additional implementationspecific information.
None.