The new method `ArrayHandle::DeepCopy` had the pattern such that the
data in the `this` array was pushed to the provided destination array.
However, this is the opposite pattern used in the equivalent method in
VTK, which takes the data from the provided array and copies it to
`this` array.
So, swap the pattern to match that of VTK. Also, make the method name
more descriptive by renaming it to `DeepCopyFrom`. Hopefully, users will
read that to mean given the `ArrayHandle`, you copy data from the other
provided `ArrayHandle`.
4345fe26b Store the number of bits of a BitField in the Buffer's metadata
da0403be7 Add metadata to Buffer object.
a84891cd3 Update ArrayHandleBitField to new array style with Buffer
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !2218
The number of bits in a `BitField` cannot be directly implied from the
size of the buffer (because the buffer gets padded to the nearest sized
word). Thus, the `BitField stored the number of bits in its own
internals.
Unfortunately, that caused issues when passing the `BitField` data
between it and an `ArrayHandleBitField`. If the `ArrayHandleBitField`
resized itself, the `BitField` would not see the new size because it
ignored the new buffer size.
To get around this problem, `BitField` now declares its own
`BufferMetaData` that stores the number of bits. Now, since the number
of bits is stored in the `Buffer` object, it is sufficient to just share
the `Buffer` to synchronize all of the state.
One of the goals of the `Buffer` object is to allow sharing of data
among objects that will interpret the data differently or give a
different interface over the data. However, when sharing only the array,
important metadata can become lost.
Provide a field that can store some custom metadata in the buffer object
so that the rest of the state can follow the buffer object around.
`ArrayHandle::PrepareForOutput` often has to reallocate the array to the
specified size. Previously, this allocation was not happening with the
`Token` that is passed to `PrepareForOutput`. If the `ArrayHandle` is
already attached or enqueued for that `Token`, then the allocation would
deadlock.
You can now pass a `Token` object to `Allocate`, which is what
`PrepareForOutput` does.
Often when a user gives memory to an `ArrayHandle`, she wants data to be
written into the memory given to be used elsewhere. Previously, the
`Buffer` objects would delete the given buffer as soon as a write buffer
was created elsewhere. That was a problem if a user wants VTK-m to write
results right into a given buffer.
Instead, when a user provides memory, "pin" that memory so that the
`ArrayHandle` never deletes it.
The buffer class encapsulates the movement of raw C arrays between
host and devices.
The `Buffer` class itself is not associated with any device. Instead,
`Buffer` is used in conjunction with a new templated class named
`DeviceAdapterMemoryManager` that can allocate data on a given
device and transfer data as necessary. `DeviceAdapterMemoryManager`
will eventually replace the more complicated device adapter classes
that manage data on a device.
The code in `DeviceAdapterMemoryManager` is actually enclosed in
virtual methods. This allows us to limit the number of classes that
need to be compiled for a device. Rather, the implementation of
`DeviceAdapterMemoryManager` is compiled once with whatever compiler
is necessary, and then the `RuntimeDeviceInformation` is used to
get the correct object instance.
