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@@ -79,6 +79,42 @@ In the same vein, accumulation of results in the same data can become a
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bottleneck. The use of the @code{STARPU_REDUX} mode permits to optimize such
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accumulation (@pxref{Data reduction}).
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+Applications often need a data just for temporary results. In such a case,
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+registration can be made without an initial value, for instance this produces a vector data:
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+
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+@cartouche
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+@smallexample
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+starpu_vector_data_register(&handle, -1, 0, n, sizeof(float));
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+@end smallexample
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+@end cartouche
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+
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+StarPU will then allocate the actual buffer only when it is actually needed,
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+e.g. directly on the GPU without allocating in main memory.
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+
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+In the same vein, once the temporary results are not useful any more, the
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+data should be thrown away. If the handle is not to be reused, it can be
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+unregistered:
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+
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+@cartouche
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+@smallexample
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+starpu_unregister_submit(handle);
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+@end smallexample
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+@end cartouche
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+
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+actual unregistration will be done after all tasks working on the handle
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+terminate.
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+
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+If the handle is to be reused, instead of unregistering it, it can simply be invalidated:
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+
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+@cartouche
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+@smallexample
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+starpu_invalidate_submit(handle);
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+@end smallexample
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+@end cartouche
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+
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+the buffers containing the current value will then be freed, and reallocated
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+only when another task writes some value to the handle.
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+
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@node Task granularity
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@section Task granularity
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