Comparison Changes During Zero Order Forward Mode
Keywords: comparison changes during zero order forward mode Adfun Comparechange syntax deprecated 2015-01-20 purpose f c discussion

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Comparison Changes During Zero Order Forward Mode
Syntax
`c = f.CompareChange()` `
` See Also FunCheck
Deprecated 2015-01-20
This routine has been deprecated, use compare_change instead.
Purpose
We use F : B n → B m to denote the AD function corresponding to `f` . This function may be not agree with the algorithm that was used to create the corresponding AD of `Base` operation sequence because of changes in AD comparison results. The `CompareChange` function can be used to detect these changes.
f
The object `f` has prototype `
const ADFun<Base> f
`
c
The result `c` has prototype `
size_t c
` It is the number of `AD<Base>` comparison operations, corresponding to the previous call to Forward `
f.Forward(0, x)
` that have a different result from when `F` was created by taping an algorithm.
Discussion
If `c` is not zero, the boolean values resulting from some of the comparison operations corresponding to `x` are different from when the AD of `Base` operation sequence was created. In this case, you may want to re-tape the algorithm with the independent variables equal to the values in `x` (so AD operation sequence properly represents the algorithm for this value of independent variables). On the other hand, re-taping the AD operation sequence usually takes significantly more time than evaluation using forward_zero . If the functions values have not changed (see FunCheck ) it may not be worth re-taping a new AD operation sequence.

Input File: omh/deprecated/compare_change.omh