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Experimental Features and Extensions

The mdsplus.ext package provides features that in development, or otherwise not ready for prime time.

GetManyMany

The GetManyMany class provides an interface for accessing many things from many shots. It will create up to num_workers threads with one mdsthin.Connection object each, and series of GetMany objects to complete all the queries. You can then iterate over the results as they come in.

from mdsthin.ext import GetManyMany

gmm = GetManyMany(SERVER, num_workers=8)

gmm.append('y', '_sig = \\IP')
gmm.append('x', 'dim_of(_sig)')
# ...

gmm.add_shots(TREE, [ SHOTS...])
# ...

# Process the results one at a time
for result in gmm.execute():
    print(result.tree, result.shot)
    print(result.get('y').data())
    print(result.get('x').data())

# Or wait for them all to complete
all_results = list(gmm.execute())

When using ssh:// or sshp://, you may need to put a small delay in-between each connection to avoid getting flagged as "too many connections appearing too quickly". If you find your connections are failing in this way, you can use the worker_delay argument to provide a delay in seconds.

gmm = GetManyMany(SERVER, worker_delay=0.1)

Tree

The Tree class approximates the regular MDSplus.Tree class, but layered on top of thin client. This means that properties such as node.isWriteOnce() will translate to expressions such as conn.get('getnci($,"WRITE_ONCE")', nid), allowing you to (almost) seamlessly use the object-based API with mdsthin. While it is not possible to provide the full API, this should be a suitable replacement for most use cases. To create a Tree you first need a Connection, or at least a host to connect to. Here are the options for defining the connection to use:

  • You can set $MDS_HOST which will be used to set the default connection automatically
export MDS_HOST=myserver
from mdsthin.ext import Tree

t = Tree(TREE, SHOT)
# ...
  • You can set a default connection
from mdsthin import Connection
from mdsthin.ext import Tree, setDefaultConnection

c = Connection('myserver')
setDefaultConnection(c)

t = Tree(TREE, SHOT)
# ...
  • You can pass the connection directly
from mdsthin import Connection
from mdsthin.ext import Tree

c = Connection('myserver')

t = Tree(TREE, SHOT, conn=c)
# ...

These features are also available in the MDSplus compatibility package:

from mdsthin import MDSplus

t = MDSplus.Tree(...)
# ...