[DOCS] Add save_param_dict, readme (#42)

nnvm/README.md

@@ -3,16 +3,54 @@
 [![Build Status](https://travis-ci.org/dmlc/nnvm.svg?branch=master)](https://travis-ci.org/dmlc/nnvm)
 [![GitHub license](http://dmlc.github.io/img/apache2.svg)](./LICENSE)
 
-NNVM is a reusable computational graph optimization and compilation stack for deep learning systems.
-NNVM provides modules to:
+NNVM is a reusable computational graph optimization and compilation stack for deep learning systems. It provides modules to:
 
 - Represent deep learning workloads from front-end frameworks via a graph IR.
 - Optimize computation graphs to improve performance.
 - Compile into executable modules and deploy to different hardware backends with minimum dependency.
 
-NNVM is designed to add new frontend, operators and graph optimizations in a decentralized fashion without changing the core interface. NNVM is part of [TVM stack](https://github.com/dmlc/tvm), which provides an end to end IR compilation stack for deploying deep learning workloads into different hardware backends
+NNVM is designed to add new frontend, operators and graph optimizations in a decentralized fashion without changing the core interface. NNVM is part of [TVM stack](https://github.com/dmlc/tvm). NNVM compiler toolchain can target hardware backends supported by TVM.
+The compiled module can be deployed to server, mobile, embedded devices and browsers with minimum dependency, in languages including c++, python, javascript, java, objective-c.
+
+The following code snippet demonstrates the general workflow of nnvm compiler toolchain.
+
+```python
+import tvm
+from tvm.contrib import graph_runtime, rpc
+import nnvm.frontend
+import nnvm.compiler
+
+# get model from frameworks
+# change xyz to supported framework name.
+graph, params = nnvm.frontend.from_xyz(...)
+
+# optimize and compile the graph to get a deployable module
+# target can be "opencl", "llvm", "metal" or any target supported by tvm
+target = "cuda"
+graph, lib, params = nnvm.compiler.build(
+   graph, target, shape={"data", data_shape}, params=params)
+
+# deploy and run on gpu(0)
+module = graph_runtime.create(graph, lib, tvm.gpu(0))
+module.set_input(**params)
+output = tvm.nd.empty(out_shape, ctx=tvm.gpu(0))
+for data_array in dataset:
+    module.set_input("data", data_array)
+    module.run()
+    module.get_output(0, output)
+
+# deploy to remote mobile/rasp/browser with minimum tvm rpc runtime
+# useful for quick experiments on mobile devices
+remote = rpc.connect(remote_host, remote_port)
+lib.export_library("mylib.so")
+remote.upload("mylib.so")
+rlib = rpc.load_module("mylib.so")
+# run on remote device
+rmodule = graph_runtime.create(graph, rlib, remote.gpu(0))
+rmodule.set_input(**params)
+rmodule.run()
+```
 
 ## Links
 - [TinyFlow](https://github.com/tqchen/tinyflow) on how you can use  NNVM to build a TensorFlow like API.
 - [Apache MXNet](http://mxnet.io/) uses NNVM as a backend.
-

nnvm/docs/api/python/compiler.rst

@@ -7,6 +7,10 @@ nnvm.compiler
 
 .. autofunction:: nnvm.compiler.build_config
 
+.. autofunction:: nnvm.compiler.save_param_dict
+
+.. autofunction:: nnvm.compiler.load_param_dict
+
 .. autofunction:: nnvm.compiler.optimize
 
 .. automodule:: nnvm.compiler.graph_util

nnvm/python/nnvm/compiler/__init__.py

@@ -1,6 +1,7 @@
 """NNVM compiler toolchain.
 
-User only need to use :any:`build` and :any:`build_config` to do the compilation.
+User only need to use :any:`build` and :any:`build_config` to do the compilation,
+and :any:`save_param_dict` to save the parameters into bytes.
 The other APIs are for more advanced interaction with the compiler toolchain.
 """
 from __future__ import absolute_import
@@ -10,6 +11,7 @@
 from . import build_module
 from . build_module import build, optimize, build_config
 from . compile_engine import engine, graph_key
+from . param_dict import save_param_dict, load_param_dict
 
 from .. import symbol as _symbol
 from .. import graph as _graph

nnvm/python/nnvm/compiler/build_module.py

@@ -9,7 +9,7 @@
 from .. import graph as _graph
 
 OPT_PASS_LEVEL = {
-    "SimplifyInference": 2,
+    "SimplifyInference": 0,
     "PrecomputePrune": 2,
     "OpFusion": 1
 }
@@ -26,6 +26,7 @@ class BuildConfig(object):
     current = None
     defaults = {
         "opt_level": 2,
+        "add_pass": None,
     }
     def __init__(self, **kwargs):
         self._old_scope = None
@@ -53,6 +54,23 @@ def __exit__(self, ptype, value, trace):
         assert self._old_scope
         BuildConfig.current = self._old_scope
 
+    def pass_enabled(self, pass_name):
+        """Get whether pass is enabled.
+
+        Parameters
+        ----------
+        pass_name : str
+            The optimization pass name
+
+        Returns
+        -------
+        enabled : bool
+            Whether pass is enabled.
+        """
+        if self.add_pass and pass_name in self.add_pass:
+            return True
+        return self.opt_level >= OPT_PASS_LEVEL[pass_name]
+
 
 BuildConfig.current = BuildConfig()
 
@@ -64,6 +82,9 @@ def build_config(**kwargs):
     opt_level: int, default=2
         Optimization level. See OPT_PASS_LEVEL for level of each pass.
 
+    add_pass: set of str
+        Optimization pass to be added regardless of optimization level.
+
     Returns
     -------
     config: BuildConfig
@@ -120,7 +141,7 @@ def optimize(graph, shape, dtype="float32"):
     """
     # pylint: disable=unused-argument
     cfg = BuildConfig.current
-    if cfg.opt_level >= OPT_PASS_LEVEL["SimplifyInference"]:
+    if cfg.pass_enabled("SimplifyInference"):
         graph = graph_attr.set_shape_inputs(graph, shape)
         graph = graph.apply(["InferShape", "SimplifyInference"])
     return graph
@@ -182,14 +203,17 @@ def build(graph, target, shape, dtype="float32", params=None):
     # Apply optimization
     graph = optimize(graph, shape, dtype)
     # Precompute prune
-    if params and cfg.opt_level >= OPT_PASS_LEVEL["PrecomputePrune"]:
+    if params and cfg.pass_enabled("PrecomputePrune"):
         graph, params = precompute_prune(graph, params)
         shape, dtype = _update_shape_dtype(shape, dtype, params)
     # Operator Fusion and generatiom
     graph = graph_attr.set_shape_inputs(graph, shape)
     graph = graph_attr.set_dtype_inputs(graph, dtype)
     graph._set_json_attr("target", target, "str")
-    graph._set_json_attr("opt_level", cfg.opt_level, "int")
+    if cfg.pass_enabled("OpFusion"):
+        graph._set_json_attr("opt_level", 1, "int")
+    else:
+        graph._set_json_attr("opt_level", 0, "int")
     graph = graph.apply("InferShape").apply("InferType")
     graph = graph.apply("GraphFusePartition").apply("GraphFuseCompile")
     libmod = graph_attr._move_out_module(graph, "module")

nnvm/python/nnvm/compiler/param_dict.py

@@ -0,0 +1,66 @@
+"""Helper utility to save parameter dict"""
+import tvm
+
+_save_param_dict = tvm.get_global_func("nnvm.compiler._save_param_dict")
+_load_param_dict = tvm.get_global_func("nnvm.compiler._load_param_dict")
+
+def save_param_dict(params):
+    """Save parameter dictionary to binary bytes.
+
+    The result binary bytes can be loaded by the
+    GraphModule with API "load_params".
+
+    Parameters
+    ----------
+    params : dict of str to NDArray
+        The parameter dictionary.
+
+    Returns
+    -------
+    param_bytes: bytearray
+        Serialized parameters.
+
+    Examples
+    --------
+    .. code-block:: python
+
+       # compile and save the modules to file.
+       graph, lib, params = nnvm.compiler.build(
+          graph, target, shape={"data", data_shape}, params=params)
+       module = graph_runtime.create(graph, lib, tvm.gpu(0))
+       # save the parameters as byte array
+       param_bytes = nnvm.compiler.save_param_dict(params)
+       # We can serialize the param_bytes and load it back later.
+       # Pass in byte array to module to directly set parameters
+       module["load_params"](param_bytes)
+    """
+    args = []
+    for k, v in params.items():
+        args.append(k)
+        args.append(tvm.nd.array(v))
+    return _save_param_dict(*args)
+
+
+def load_param_dict(param_bytes):
+    """Load parameter dictionary to binary bytes.
+
+    Parameters
+    ----------
+    param_bytes: bytearray
+        Serialized parameters.
+
+    Returns
+    -------
+    params : dict of str to NDArray
+        The parameter dictionary.
+    """
+    if isinstance(param_bytes, (bytes, str)):
+        param_bytes = bytearray(param_bytes)
+    load_mod = _load_param_dict(param_bytes)
+    size = load_mod(0)
+    param_dict = {}
+    for i in range(size):
+        key = load_mod(1, i)
+        dltensor_handle = load_mod(2, i)
+        param_dict[key] = tvm.nd.NDArray(dltensor_handle, False)
+    return param_dict

nnvm/python/nnvm/graph.py

@@ -12,7 +12,7 @@
 from ._base import c_array, c_str, nn_uint, py_str, string_types
 from ._base import GraphHandle, SymbolHandle
 from ._base import check_call
-from .symbol import Symbol, Group as _Group
+from .symbol import Variable, Symbol, Group as _Group
 
 class GraphIndex(object):
     """Index for quickly accessing graph attributes.
@@ -174,9 +174,19 @@ def symbol(self):
         check_call(_LIB.NNGraphGetSymbol(self.handle, ctypes.byref(shandle)))
         return Symbol(shandle)
 
+    def json(self):
+        """Get JSON representation of the graph
+
+        Returns
+        -------
+        json : str
+            JSON representation of the graph
+        """
+        return self.apply("SaveJSON").json_attr("json")
+
     def _tvm_graph_json(self):
         """Get TVM graph json"""
-        return self.apply("SaveJSON").json_attr("json")
+        return self.json()
 
     @property
     def index(self):
@@ -225,6 +235,24 @@ def apply(self, passes):
         return Graph(ghandle)
 
 
+def load_json(json_str):
+    """Create a new graph by loading from json
+
+    Parameters
+    ----------
+    json_str : str
+        The json string
+
+    Returns
+    -------
+    graph : Graph
+        The loaded graph
+    """
+    ret = create(Variable("x"))
+    ret._set_json_attr("json", json_str)
+    return ret.apply("LoadJSON")
+
+
 def create(symbol):
     """Create a new graph from symbol.
 

nnvm/src/compiler/graph_fuse.cc

@@ -15,46 +15,10 @@
 #include <tvm/lowered_func.h>
 #include <dmlc/parameter.h>
 #include "./compile_engine.h"
-#include "../../tvm/src/runtime/graph/graph_runtime.h"
+#include "./graph_runtime.h"
 
 namespace nnvm {
 namespace compiler {
-
-
-struct TVMOpParam : public dmlc::Parameter<TVMOpParam> {
-  std::string func_name;
-  uint32_t num_inputs;
-  uint32_t num_outputs;
-  uint32_t flatten_data;
-
-  DMLC_DECLARE_PARAMETER(TVMOpParam) {
-    DMLC_DECLARE_FIELD(func_name);
-    DMLC_DECLARE_FIELD(num_inputs).set_default(1);
-    DMLC_DECLARE_FIELD(num_outputs).set_default(1);
-    DMLC_DECLARE_FIELD(flatten_data).set_default(0);
-  }
-};
-
-DMLC_REGISTER_PARAMETER(TVMOpParam);
-
-// parser
-inline void TVMOpParamParser(nnvm::NodeAttrs* attrs) {
-  TVMOpParam param;
-  param.Init(attrs->dict);
-  attrs->parsed = std::move(param);
-}
-
-NNVM_REGISTER_OP(tvm_op)
-.set_attr_parser(TVMOpParamParser)
-.set_num_inputs([](const NodeAttrs& attrs) {
-    const TVMOpParam& param = nnvm::get<TVMOpParam>(attrs.parsed);
-    return param.num_inputs;
-  })
-.set_num_outputs([](const NodeAttrs& attrs) {
-    const TVMOpParam& param = nnvm::get<TVMOpParam>(attrs.parsed);
-    return param.num_outputs;
-  });
-
 using namespace tvm;
 
 // The single fuse rule.