\(\newcommand{\W}[1]{ \; #1 \; }\) \(\newcommand{\R}[1]{ {\rm #1} }\) \(\newcommand{\B}[1]{ {\bf #1} }\) \(\newcommand{\D}[2]{ \frac{\partial #1}{\partial #2} }\) \(\newcommand{\DD}[3]{ \frac{\partial^2 #1}{\partial #2 \partial #3} }\) \(\newcommand{\Dpow}[2]{ \frac{\partial^{#1}}{\partial {#2}^{#1}} }\) \(\newcommand{\dpow}[2]{ \frac{ {\rm d}^{#1}}{{\rm d}\, {#2}^{#1}} }\)
multi_thread¶
View page sourceUsing CppAD in a Multi-Threading Environment¶
Purpose¶
Extra steps and care must be taken to use CppAD in parallel execution mode. This section collects this information in one place.
CPPAD_MAX_NUM_THREADS¶
The value CPPAD_MAX_NUM_THREADS is an absolute maximum for
the number of threads that CppAD should support.
If this preprocessor symbol is defined
before including any CppAD header files,
it must be an integer greater than or equal to one.
Otherwise, cppad_max_num_threads
is used to define this preprocessor symbol.
Note that the minimum allowable value for
cppad_max_num_threads is 4; i.e., you can only
get smaller values for CPPAD_MAX_NUM_THREADS by
defining it before including the CppAD header files.
parallel_setup¶
Using any of the following routines in a multi-threading environment requires that thread_alloc::parallel_setup has been completed: CppAD::vector , CheckSimpleVector , CheckNumericType , parallel_ad .
hold_memory¶
Memory allocation should be much faster after calling
hold_memory with
value equal to true.
This may even be true if there is only one thread.
Parallel AD¶
One must first call
thread_alloc::parallel_setup
and then call parallel_ad before using AD types
in parallel execution mode.
In addition, see Other Initialization .
Same Thread¶
Some operations must be preformed by the same thread: ADFun , Independent , Dependent .
Parallel Prohibited¶
The following routine cannot be called in parallel mode: ErrorHandler constructor .
Contents¶
Name |
Title |
|---|---|
parallel_ad |
|
thread_test.cpp |