[DOC] Pool Memory resource

[tfeher]

Report incorrect documentation

Location of incorrect documentation
Incorrect code examples for PoolMemoryResource at:

• https://docs.rapids.ai/api/rmm/nightly/basics.html#using-rmm
• https://github.com/rapidsai/rmm/#memoryresource-objects

Incorrect code:

import rmm
pool = rmm.mr.PoolMemoryResource(
    upstream=rmm.mr.CudaMemoryResource(),
    initial_pool_size=2**30,
    maximum_pool_size=2**32)
rmm.mr.set_current_device_resource(pool)

Describe the problems or issues found in the documentation

The code example gives the following error:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-4-7cd0585a0d02> in <module>
      1 import rmm
----> 2 pool = rmm.mr.PoolMemoryResource(
      3     upstream=rmm.mr.CudaMemoryResource(),
      4     initial_pool_size=2**30,
      5     maximum_pool_size=2**32)

rmm/_lib/memory_resource.pyx in rmm._lib.memory_resource.UpstreamResourceAdaptor.__cinit__()

TypeError: __cinit__() takes at least 1 positional argument (0 given)

Steps taken to verify documentation is incorrect
Run the code example above.

Suggested fix for documentation
Remove the upstream keyword.

import rmm
pool = rmm.mr.PoolMemoryResource(
    rmm.mr.CudaMemoryResource(),
    initial_pool_size=2**30,
    maximum_pool_size=2**32)
rmm.mr.set_current_device_resource(pool)