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ParallelOptions Class Reference | ![]() |
Option base class for parallel algorithms. More...
#include <vigra/threadpool.hxx>
Public Types | |
| enum | { Auto = -1, Nice = -2, NoThreads = 0 } |
Public Member Functions | |
| int | getActualNumThreads () const |
| Get desired number of threads. More... | |
| int | getNumThreads () const |
| Get desired number of threads. More... | |
| ParallelOptions & | numThreads (const int n) |
Set the number of threads or one of the constants Auto, Nice and NoThreads. More... | |
Option base class for parallel algorithms.
#include <vigra/threadpool.hxx>
Namespace: vigra
| anonymous enum |
| int getNumThreads | ( | ) | const |
Get desired number of threads.
Note: This function may return 0, which means that multi-threading shall be switched off entirely. If an algorithm receives this value, it should revert to a sequential implementation. In contrast, if numThread() == 1, the parallel algorithm version shall be executed with a single thread.
| int getActualNumThreads | ( | ) | const |
Get desired number of threads.
In contrast to numThread(), this will always return a value >=1.
| ParallelOptions& numThreads | ( | const int | n | ) |
Set the number of threads or one of the constants Auto, Nice and NoThreads.
Default: ParallelOptions::Auto (use system default)
This setting is ignored if the preprocessor flag VIGRA_SINGLE_THREADED is defined. Then, the number of threads is set to 0 and all tasks revert to sequential algorithm implementations. The same can be achieved at runtime by passing n = 0 to this function. In contrast, passing n = 1 causes the parallel algorithm versions to be executed with a single thread. Both possibilities are mainly useful for debugging.
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© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de) |
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