1Blurb::
2Deactivate the Active Set Vector
3
4Description::
5Allows the user to turn off any variability in ASV values so that
6active set logic can be omitted in the user's simulation
7interface. This option trades some efficiency for simplicity in
8interface development.
9
10The default behavior is to request the minimum amount of data required
11by an algorithm at any given time, which implies that the ASV values
12may vary from one function evaluation to the next. Since the user's
13interface must return the data set requested by the ASV values, this
14interface must contain additional logic to account for any variations
15in ASV content.
16
17Deactivating this ASV control causes %Dakota to always request a
18"full" data set (the full function, gradient, and Hessian data that is
19available from the interface as specified in the responses
20specification) on each function evaluation.
21
22For example, if ASV control has been deactivated and the responses
23section specifies four response functions, analytic gradients, and no
24Hessians, then the ASV on every function evaluation will be { 3 3 3 3
25}, regardless of what subset of this data is currently needed. While
26wasteful of computations in many instances, this simplifies the
27interface and allows the user to return the same data set on every
28evaluation.  Conversely, if ASV control is active (the default
29behavior), then the ASV requests in this example might vary from { 1 1
301 1 } to { 2 0 0 2 }, etc., according to the specific data needed on a
31particular function evaluation. This will require the user's interface
32to read the ASV requests and perform the appropriate logic in
33conditionally returning only the data requested.
34
35<b>Usage Tips</b>
36
37\li In general, the default ASV behavior is recommended for the sake
38    of computational efficiency, unless interface development time is
39    a critical concern.
40
41\li Whether active or inactive, the data returned to %Dakota from the
42    user's interface must match the ASV passed in, or else a response
43    recovery error will result. However, when the ASV control is
44    deactivated, the ASV values are invariant and need not be checked
45    on every evaluation.
46
47\li Deactivating the ASV control can have a positive effect on load
48    balancing for parallel %Dakota executions. Thus, there is
49    significant overlap in this ASV control option with speculative
50    gradients.  There is also overlap with the mode override approach
51    used with certain optimizers to combine individual value,
52    gradient, and Hessian requests.
53
54Topics::
55Examples::
56Theory::
57Faq::
58See_Also::
59