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[notebook - customOps] Finished first version of CustomOp notebook

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%% Cell type:markdown id: tags:
# FINN - CustomOps
-----------------------------------------------------------------
<font size="3">This notebook should give a more detailed insight into FINN custom operation nodes. </font>
%% Cell type:markdown id: tags:
<font size="3">Following showSrc function is used to print the source code of function calls in the Jupyter notebook: </font>
%% Cell type:code id: tags:
``` python
import inspect
def showSrc(what):
print("".join(inspect.getsourcelines(what)[0]))
```
%% Cell type:markdown id: tags:
## FINN Custom Ops
---------------------------
<font size="3">FINN uses many custom operations (`op_type` in ONNX NodeProto) that are not defined in the ONNX operator schema. These custom nodes are marked with `domain="finn"` in the protobuf to identify them as such. These nodes can represent specific operations that we need for low-bit networks, or operations that are specific to a particular hardware backend.
A very abstract version of a custom op node representing a streaming fc layer is shown below. </font>
%% Cell type:markdown id: tags:
## Outline
---------------------------
* <font size="3">FINN-ONNX node</font>
* <font size="3">CustomOp class</font>
* <font size="3">HLSCustomOp class</font>
%% Cell type:markdown id: tags:
## FINN-ONNX node
<font size="3">To create a FINN-ONNX node you can use the helper function of ONNX. Because it is an ONNX NodeProtobuf, but with several additional attributes. </font>
`FCLayer_node = helper.make_node(
"StreamingFCLayer_Batch",
node_inp_list,
node_outp_list,
domain="finn",
backend="fpgadataflow",
code_gen_dir="",
executable_path="",
resType="ap_resource_lut()",
MW=mw,
MH=mh,
SIMD=simd,
PE=pe,
inputDataType=<FINN DataType>,
weightDataType=<FINN DataType>,
outputDataType=<FINN DataType>,
ActVal=actval,
binaryXnorMode=<0/1>,
noActivation=<0/1>
)`
%% Cell type:markdown id: tags:
<font size="3">Unlike standard nodes, the custom op nodes has several additional attributes. The node is created using the helper function of ONNX. `"StreamingFCLayer_Batch"` describes the op_type, then the inputs and outputs are declared. Since this is a custom op node of FINN, the attribute `domain="finn"` must be set. The streaming fc layer is a custom op from the finn-hls library, this is set in the node using the `backend` attribute. To execute a custom op from the finn-hls library, the corresponding c++ code must be created and an executable must be produced. Where the generated code is stored is specified in the `code_gen_dir` attribute and `executable_path` specifies the path to the produced executable. In addition to the data types of the input and output tensors, the node also contains various other attributes resulting from the parameters of the corresponding finn-hls library function. This will not be discussed here.</font>
<font size="3">`"StreamingFCLayer_Batch"` describes the op_type, then the inputs and outputs are declared. This is still like building a default onnx node without additional attributes. But since this is a custom op node of FINN, the attribute `domain="finn"` must be set. The streaming fc layer is a custom op from the finn-hls library, this information is set in the node using the `backend` attribute. To execute a custom op from the finn-hls library, the corresponding c++ code must be created and an executable must be produced. Where the generated code is stored is specified in the `code_gen_dir` attribute and `executable_path` specifies the path to the produced executable. In addition to the data types of the input and output tensors, the node also contains various other attributes resulting from the parameters of the corresponding finn-hls library function. More detailed information can be found in the documentation of [finn-hlslib](github.com/Xilinx/finn-hlslib).</font>
%% Cell type:markdown id: tags:
<font size="3">Custom Ops are represented in FINN as ONNX nodes on the one hand and by a CustomOp class on the other hand. This allows easier access to the different attributes and introduces special custom op functions. See below for the standard CustomOp class.</font>
## CustomOp class
<font size="3">Custom Ops are represented in FINN as ONNX nodes on the one hand and by a CustomOp class on the other hand. This allows easier access to different attributes and introduces special custom op functions. See below for the standard CustomOp class.</font>
%% Cell type:code id: tags:
``` python
from finn.custom_op import CustomOp
showSrc(CustomOp)
```
%% Output
class CustomOp(ABC):
def __init__(self, onnx_node):
super().__init__()
self.onnx_node = onnx_node
def get_nodeattr(self, name):
"""Get a node attribute by name. Data is stored inside the ONNX node's
AttributeProto container. Attribute must be part of get_nodeattr_types.
Default value is returned if attribute is not set."""
try:
(dtype, req, def_val) = self.get_nodeattr_types()[name]
attr = get_by_name(self.onnx_node.attribute, name)
if attr is not None:
# dtype indicates which ONNX Attribute member to use
# (such as i, f, s...)
ret = attr.__getattribute__(dtype)
if dtype == "s":
# decode string attributes
ret = ret.decode("utf-8")
return ret
else:
# not set, return default value
return def_val
except KeyError:
raise AttributeError("Op has no such attribute: " + name)
def set_nodeattr(self, name, value):
"""Set a node attribute by name. Data is stored inside the ONNX node's
AttributeProto container. Attribute must be part of get_nodeattr_types."""
try:
(dtype, req, def_val) = self.get_nodeattr_types()[name]
attr = get_by_name(self.onnx_node.attribute, name)
if attr is not None:
# dtype indicates which ONNX Attribute member to use
# (such as i, f, s...)
if dtype == "s":
# encode string attributes
value = value.encode("utf-8")
attr.__setattr__(dtype, value)
else:
# not set, create and insert AttributeProto
attr_proto = helper.make_attribute(name, value)
self.onnx_node.attribute.append(attr_proto)
except KeyError:
raise AttributeError("Op has no such attribute: " + name)
@abstractmethod
def get_nodeattr_types(self):
"""Returns a dict of permitted attributes for node, where:
returned_dict[attribute_name] = (dtype, require, default_value)
- dtype indicates which member of the ONNX AttributeProto
will be utilized
- require indicates whether this attribute is required
- default_val indicates the default value that will be used if the
attribute is not set
"""
pass
@abstractmethod
def make_shape_compatible_op(self):
"""Returns a standard ONNX op which is compatible with this CustomOp
for performing shape inference."""
pass
@abstractmethod
def infer_node_datatype(self, model):
"""Set the DataType annotations corresponding to the outputs of this
node."""
pass
@abstractmethod
def execute_node(self, context, graph):
"""Execute this CustomOp instance, given the execution context and
ONNX graph."""
pass
%% Cell type:markdown id: tags:
<font size="3">When instantiating the class, the ONNX node is passed to access all attributes of the node within the class. This is accompanied by the functions `get_nodeattr()`and `set_nodeattr()`, which each instance of this class has. Furthermore 4 abstract methods are implemented, which are described in more detail in the comments in the code. </font>
%% Cell type:markdown id: tags:
## HLSCustomOp class
<font size="3">If it is a node from the finn-hls library another class is used which is derived from the CustomOp class:</font>
%% Cell type:code id: tags:
``` python
from finn.custom_op.fpgadataflow import HLSCustomOp
showSrc(HLSCustomOp)
```
%% Output
class HLSCustomOp(CustomOp):
def __init__(self, onnx_node):
super().__init__(onnx_node)
# template for single node execution
self.docompute_template = """
#include "cnpy.h"
#include "npy2apintstream.hpp"
#include <vector>
#include "bnn-library.h"
// includes for network parameters
$GLOBALS$
// defines for network parameters
$DEFINES$
int main(){
$STREAMDECLARATIONS$
$READNPYDATA$
$DOCOMPUTE$
$DATAOUTSTREAM$
$SAVEASCNPY$
}
"""
self.code_gen_dict = {}
def get_nodeattr_types(self):
return {"code_gen_dir": ("s", False, ""), "executable_path": ("s", False, "")}
def code_generation(self, model):
node = self.onnx_node
self.generate_params(model)
self.global_includes()
self.defines()
self.read_npy_data()
self.strm_decl()
self.docompute()
self.dataoutstrm()
self.save_as_npy()
template = self.docompute_template
for key in self.code_gen_dict:
# transform list into long string separated by '\n'
code_gen_line = "\n".join(self.code_gen_dict[key])
template = template.replace(key, code_gen_line)
code_gen_dir = self.get_nodeattr("code_gen_dir")
f = open(os.path.join(code_gen_dir, "execute_{}.cpp".format(node.op_type)), "w")
f.write(template)
f.close()
def compile_singlenode_code(self):
code_gen_dir = self.get_nodeattr("code_gen_dir")
builder = CppBuilder()
builder.append_includes("-I/workspace/finn/src/finn/data/cpp")
builder.append_includes("-I/workspace/cnpy/")
builder.append_includes("-I/workspace/finn-hlslib")
builder.append_includes("-I/workspace/vivado-hlslib")
builder.append_includes("--std=c++11")
builder.append_sources(code_gen_dir + "/*.cpp")
builder.append_sources("/workspace/cnpy/cnpy.cpp")
builder.append_includes("-lz")
builder.set_executable_path(code_gen_dir + "/node_model")
builder.build(code_gen_dir)
self.set_nodeattr("executable_path", builder.executable_path)
def dynamic_input_to_npy(self, context, count):
node = self.onnx_node
code_gen_dir = self.get_nodeattr("code_gen_dir")
if code_gen_dir == "":
raise Exception(
"""
Found no codegen dir for this node, did you run the codegen transformation?
"""
)
# create a npy file for each input of the node (in_ind is input index)
# assuming dynamic inputs start from 0
for in_ind in range(count):
current_input_name = node.input[in_ind]
np.save(
os.path.join(code_gen_dir, "input_{}.npy".format(in_ind)),
context[current_input_name],
)
def npy_to_dynamic_output(self, context):
# TODO support multi-output nodes as needed
node = self.onnx_node
code_gen_dir = self.get_nodeattr("code_gen_dir")
output = np.load("{}/output.npy".format(code_gen_dir))
context[node.output[0]] = output
def exec_precompiled_singlenode_model(self):
# execute precompiled executable
executable_path = self.get_nodeattr("executable_path")
if executable_path == "":
raise Exception(
"""
Found no executable for this node, did you run the codegen and
compilation transformations?
"""
)
process_execute = subprocess.Popen(executable_path, stdout=subprocess.PIPE)
process_execute.communicate()
def execute_node(self, context, graph):
# save input(s)
self.dynamic_input_to_npy(context, 1)
# execute the precompiled model
self.exec_precompiled_singlenode_model()
# load output npy file
self.npy_to_dynamic_output(context)
def generate_params(self, model):
pass
@abstractmethod
def global_includes(self):
pass
@abstractmethod
def defines(self):
pass
@abstractmethod
def read_npy_data(self):
pass
@abstractmethod
def strm_decl(self):
pass
@abstractmethod
def docompute(self):
pass
@abstractmethod
def dataoutstrm(self):
pass
@abstractmethod
def save_as_npy(self):
pass
%% Cell type:markdown id: tags:
<font size="3">When creating an instance of this class, a template is introduced, which forms the layout for the c++ code to execute the node. It has some general constructs, like the inclusion of bnn-library.h, which contains the references to the finn-hls library, and of cnpy.h and npy2apintstream.hpp, which support the transfer of python numpy arrays in c++. The idea of this template is to replace the variables marked with `$ $` with c++ calls during code generation. Then the template can be written into a .cpp file and be compiled.
**`get_nodeattr_types()`**: each instance of the HLSCustomOp class must have the attributes `code_gen_dir` and `executable_path`, since to execute these nodes c++ code must be generated and correspondingly the executables.
</font>
%% Cell type:markdown id: tags:
<font size="3">**`code_generation(model)`**: all functions required for code generation are called and the `$ $` variables in the template are replaced accordingly and written into a .cpp file. Almost all of these subfunctions are implemented as abstract methods in the class, so they are completely customized for each custom op node. A special function is `generate_params()`. This is not implemented as an abstract method, but as a normal function, but contains by default only `pass`. This is because some custom op nodes do not have parameters that need to be generated and in this way the function is skipped. For example for a streaming fc layer node a parameter generation is necessary. How such a parameter generation can look like is described in more detail in the course of this notebook.
</font>
%% Cell type:markdown id: tags:
<font size="3">**`compile_singlenode_code()`**: To compile the generated code, the compile command must be built. This is done in this function. It creates an instance of the `CppBuilder()` class and assembles the various components for the function. The `.build` function creates the executable and then sets the corresponding attribute. The class `CppBuilder` is a transformation and a more detailed description can be found in Jupyter notebook *FINN-CodeGenerationAndCompilation*.
<font size="3">**`compile_singlenode_code()`**: To compile the generated code, the compile command must be built. This is done in this function. It creates an instance of the `CppBuilder()` class and assembles the various components for the function. The `.build` function creates the executable and then sets the corresponding attribute. The class `CppBuilder` is a transformation and a more detailed description can be found in Jupyter notebook [FINN-CodeGenerationAndCompilation](github.com/Xilinx/finn/blob/dev/notebooks/FINN-CodeGenerationAndCompilation.ipynb).
</font>
%% Cell type:markdown id: tags:
<font size="3">**`dynamic_input_to_npy(context, count)`**:</font>
<font size="3">**`dynamic_input_to_npy(context, count)`**: creates a .npy file for all inputs of the node. These files will be stored in the directory specified by code_gen_dir. The argument `count` must be used to specify the number of inputs. `context` contains the values for the inputs.</font>
%% Cell type:markdown id: tags:
<font size="3">**`npy_to_dynamic_output(context)`**: reads the output values and sets `context` dictionary accordingly. When executing the c++ executable of the node, the output values are written to a .npy file. </font>
%% Cell type:markdown id: tags:
<font size="3">**`exec_precompiled_singlenode_model()`**: executes precompiled executable which is specified in `executable_path`</font>
%% Cell type:markdown id: tags:
<font size="3">**`execute_node(context,graph)`**: calls first `dynamic_input_to_npy()`, then executes the executable using `exec_precompiled_singlenode_model()` and at the end reads the output .npy file with `npy_to_dynamic_output`</font>
%% Cell type:markdown id: tags:
#### Generate Parameter
<font size="3">Parameters have to be generated for specific types of HLSCustomOps. For example if the node is a streaming fc layer, there are weights and activation values, which are written to separate .h files and added to the template using `#include`. For streaming fc layer the parameter generation looks like this:
</font>
%% Cell type:code id: tags:
``` python
from finn.custom_op.fpgadataflow.streamingfclayer_batch import StreamingFCLayer_Batch
showSrc(StreamingFCLayer_Batch.generate_params)
```
%% Output
def generate_params(self, model):
# weights
weights = model.get_initializer(self.onnx_node.input[1])
# convert weights into hlslib-compatible format
weight_tensor = self.get_hls_compatible_weight_tensor(weights)
export_wdt = self.get_weight_datatype()
# we have converted bipolar weights to binary for export,
# so use it as such for weight generation
if self.get_weight_datatype() == DataType.BIPOLAR:
export_wdt = DataType.BINARY
weight_hls_code = numpy_to_hls_code(
weight_tensor, export_wdt, "weights", True, True
)
# write weights into params.h
code_gen_dir = self.get_nodeattr("code_gen_dir")
f_weights = open("{}/params.h".format(code_gen_dir), "w")
if export_wdt.bitwidth() != 1:
f_weights.write(
"static FixedPointWeights<{},{},{},{}> weights = ".format(
self.get_nodeattr("SIMD"),
export_wdt.get_hls_datatype_str(),
self.get_nodeattr("PE"),
self.calc_wmem(),
)
)
else:
f_weights.write(
"static BinaryWeights<{},{},{}> weights = ".format(
self.get_nodeattr("SIMD"), self.get_nodeattr("PE"), self.calc_wmem()
)
)
f_weights.write(weight_hls_code)
f_weights.close()
# thresholds
if len(self.onnx_node.input) > 2:
thresholds = model.get_initializer(self.onnx_node.input[2])
if thresholds is not None:
threshold_tensor = self.get_hls_compatible_threshold_tensor(thresholds)
tdt = DataType.INT32
# use UINT32 threshold export for bipolar times bipolar
inp_is_bipolar = self.get_input_datatype() == DataType.BIPOLAR
wt_is_bipolar = self.get_weight_datatype() == DataType.BIPOLAR
# reinterpret inp/wt as bipolar if bin_xnor_mode is iset
inp_is_binary = self.get_input_datatype() == DataType.BINARY
wt_is_binary = self.get_weight_datatype() == DataType.BINARY
bin_xnor_mode = self.get_nodeattr("binaryXnorMode") == 1
inp_is_bipolar = inp_is_bipolar or (inp_is_binary and bin_xnor_mode)
wt_is_bipolar = wt_is_bipolar or (wt_is_binary and bin_xnor_mode)
if inp_is_bipolar and wt_is_bipolar:
tdt = DataType.UINT32
thresholds_hls_code = numpy_to_hls_code(
threshold_tensor, tdt, "thresholds", False, True
)
# write thresholds into thresh.h
code_gen_dir = self.get_nodeattr("code_gen_dir")
f_thresh = open("{}/thresh.h".format(code_gen_dir), "w")
tdt_hls = tdt.get_hls_datatype_str()
# use binary to export bipolar activations
export_odt = self.get_output_datatype()
if self.get_output_datatype() == DataType.BIPOLAR:
export_odt = DataType.BINARY
odt_hls = export_odt.get_hls_datatype_str()
f_thresh.write(
"static ThresholdsActivation<{},{},{},{},{},{},{}> threshs \
= ".format(
self.calc_tmem(),
self.get_nodeattr("PE"),
threshold_tensor.shape[-1],
tdt_hls,
odt_hls,
self.get_nodeattr("ActVal"),
"std::less_equal<%s>" % tdt_hls,
)
)
f_thresh.write(thresholds_hls_code)
f_thresh.close()
%% Cell type:markdown id: tags:
<font size="3">First, the values for the weights are extracted with `get_initializer()` using the ModelWrapper. At this point it is assumed that the second input of the streamingfclayer specifies the weights. After a few manipulations the weights are written in `params.h`. If there are threshold values, they will be prepared and written to `thresh.h`. </font>
%% Cell type:code id: tags:
``` python
```
......
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