* Add NGRAPH_INTRA_OP_PARALLELISM to control size of thread pools.

* Initialize variable.

* Update input_validation.py

* Update runtime.py

* Update types.py

* Update broadcasting.py

* optimize concat

* compile sucess

* multi inputs

* clang format

* Testing out some ideas for better error messages on AvgPool

* Add uncaught_exception() check to ConstructionAssertLogger dtor

* More general assertion class, not homed inside Node

* Minor formatting change

* NODE_ASSERT for type prop failure

* Produce lighter-weight DummyAssertionHandler when assertion succeeds

* New ctor for AssertionHelper that takes a single location arg; more const&-ness for the constructors

* Remove move constructor for AssertionHelper; fix broken test in assertion.cpp

* Miscellaneous improvements

* Templatized AssertionHelper so different exception classes can be used; implemented TYPE_CHECK_ASSERT around this
* Changed from a "stack" of locations to a single location (the stack was too complicated)
* Added "FAIL" classes/macros which do not take a condition

* Rename a helper function

* Cleanup, cruft removal

* Add test to make sure the assert helper has the lifetime we expect

* Missing includes

* editing how to execute computation file for clarity and linenos

* Add placeholder for runtime docs

* Update section on backends, interpreter, and FPGA options

* add updated master to fix python_ci

* Weird autosummary issue reverted

* Clarify new section

* fix up docs

* Update pattern matcher doc based on Nik's presentation slides WIP

* Update doc structure and examples

* remove old folder

* Fix broken Tensorview refs

* new section on distr training

* updated index w/drafted outline

* . helping people document code more efficiently

* edit WIP branch

* WIP editing

* WIP editing

* init distributed doc

* PR review edits

* modify dist doc and dist mnist_mlp

* Finish PR review comment fixes so far

* Improving distributed training docs

* Fix build error now that we have documented inteface backends use

* update example build and run

* update how-to distributed training doc

* Editing distr train docs

* Reword section to avoid strange doc build error

* rebuild for zero errors for CI

* split patternmatcher PR

* PR feedback added

* Add more help and detail for MXNet and neon distr

* Resolve merge conflicts due to patternmatcher doc split

* Resolve merge conflicts due to patternmatcher doc split

* Resolve build errors manually

* These files are already added to the branch

* fix style

* update with glossary def and link to Intel paper on synchronous SGD

* fix link to sgd

* remove comm_rank in dist example

* Broadcast and Pad bug fix.

* IntelGPUBackend: Broadcast operation

* IntelGPUBackend: more tests for Broadcast operation

* Move macro to static C function in Broadcast tests

CPU Direct Execution Part 4

This reverts commit 549a4fd1.

* simplify inplace reshape

* relax check in emitter

and track callees within the ExternalFunction