Prev

Next

Index-> contents reference index search external

Up-> CppAD ADFun FunEval Forward size_taylor

ADFun-> Independent FunConstruct Dependent abort_recording seq_property FunEval Drivers FunCheck optimize

FunEval-> Forward Reverse Sparse

Forward-> ForwardZero ForwardOne ForwardAny size_taylor CompareChange capacity_taylor Forward.cpp

size_taylor

Headings-> Syntax ---..See Also Purpose f s Constructor Forward capacity_taylor Example

Number Taylor Coefficients, Per Variable, Currently Stored
Syntax
s = f.size_taylor()

See Also
seq_property

Purpose
Determine the number of Taylor coefficients, per variable, currently calculated and stored in the ADFun object f . See the discussion under Constructor , Forward , and capacity_taylor for a description of when this value can change.

f
The object f has prototype
     const ADFun<Base> f

s
The result s has prototype
     size_t s
and is the number of Taylor coefficients, per variable in the AD operation sequence, currently calculated and stored in the ADFun object f .

Constructor
Directly after the FunConstruct syntax
     ADFun<Base> f(x, y)
the value of s returned by size_taylor is one. This is because there is an implicit call to Forward that computes the zero order Taylor coefficients during this constructor.

Forward
After a call to Forward with the syntax
        f.Forward(p, x_p)
the value of s returned by size_taylor would be $\mathit{p}+1$ . The call to Forward above uses the lower order Taylor coefficients to compute and store the p-th order Taylor coefficients for all the variables in the operation sequence corresponding to f . Thus there are $\mathit{p}+1$ (order zero through p ) Taylor coefficients per variable. (You can determine the number of variables in the operation sequence using the size_var function.)

capacity_taylor
If the number of Taylor coefficients currently stored in f is less than or equal c , a call to capacity_taylor with the syntax
     f.capacity_taylor(c)
does not affect the value s returned by size_taylor. Otherwise, the value s returned by size_taylor is equal to c (only Taylor coefficients of order zero through $\mathit{c}-1$ have been retained).

Example
The file Forward.cpp contains an example and test of this operation. It returns true if it succeeds and false otherwise.

---

Input File: omh/forward.omh