Printing AD Values During Forward Mode

@(@\newcommand{\W}[1]{ \; #1 \; } \newcommand{\R}[1]{ {\rm #1} } \newcommand{\B}[1]{ {\bf #1} } \newcommand{\D}[2]{ \frac{\partial #1}{\partial #2} } \newcommand{\DD}[3]{ \frac{\partial^2 #1}{\partial #2 \partial #3} } \newcommand{\Dpow}[2]{ \frac{\partial^{#1}}{\partial {#2}^{#1}} } \newcommand{\dpow}[2]{ \frac{ {\rm d}^{#1}}{{\rm d}\, {#2}^{#1}} }@)@This is cppad-20221105 documentation. Here is a link to its current documentation . Printing AD Values During Forward Mode
Syntax

f.Forward(0, x)

f.Forward(0, x, s)

PrintFor(before, value)

PrintFor(notpos, before, value, after)

See Also
ad_output

Purpose
The zero order forward mode command



    f.Forward(0, x)

sets the independent variable vector equal to x . It then computes a value for all of the dependent variables in the operation sequence corresponding to f . Putting a PrintFor in the operation sequence, prints value , corresponding to x , to be printed during zero order forward operations.

f.Forward(0, x)
The objects f , x , and the purpose for this operation, are documented in Forward .

notpos
If present, the argument notpos has one of the following prototypes



    const AD<Base>&               notpos

    const VecAD<Base>::reference& notpos

In this case the text and value will be printed if and only if notpos is not positive (greater than zero) and a finite number.

before
The argument before has prototype



    const char* before

This text is written to std::cout before value .

value
The argument value has one of the following prototypes



    const AD<Base>&               value

    const VecAD<Base>::reference& value

The value , that corresponds to x , is written to std::cout during the execution of



    f.Forward(0, x)

Note that value may be a variable or parameter . If a parameter is dynamic its value will depend on the previous call to new_dynamic .

after
The argument after has prototype



    const char* after

This text is written to std::cout after value .

s
You can redirect this output to any standard output stream using the syntax



    f.Forward(0, x, s)

see s in the zero order forward mode documentation.

Discussion
This is helpful for understanding why tape evaluations have trouble. For example, if one of the operations in f is log(value) and value < 0 , the corresponding result will nan .

Example
The program print_for_cout.cpp is an example and test that prints to standard output. The output of this program states the conditions for passing and failing the test. The function print_for_string.cpp is an example and test that prints to an standard string stream. This function automatically check for correct output.

Input File: include/cppad/core/print_for.hpp