# Complete Numpy API for ONNX¶

The numpy API is meant to simplofy the creation of ONNX
graphs by using functions very similar to what numpy implements.
This page only makes a list of the available
functions. A tutorial is available at
Numpy to ONNX: Create ONNX graphs with an API similar to numpy.
This API was first added to *mlprodict* in version 0.6.

## Introduction¶

Converting custom code into ONNX is not necessarily easy.
One big obstacle is ONNX does not represent all numpy functions
with a single operator. One possible option is to provide a
numpy API to ONNX. That’s the purpose of wrapper
`onnxnumpy`

.
It takes a function written with functions following the same
signature as numpy and provides a way to execute them
with an ONNX runtime. In the below example,
custom_fct creates an ONNX graph, the wrapper
loads it in a runtime and runs it everytime the function
is called.

<<<

```
import numpy
from typing import Any
from mlprodict.npy import onnxnumpy_default, NDArray
import mlprodict.npy.numpy_onnx_impl as nxnp
@onnxnumpy_default
def custom_fct(x: NDArray[Any, numpy.float32],
) -> NDArray[Any, numpy.float32]:
"onnx numpy abs"
return nxnp.abs(x) + numpy.float32(1)
x = numpy.array([[6.1, -5], [3.5, -7.8]], dtype=numpy.float32)
y = custom_fct(x)
print(y)
```

>>>

```
[[7.1 6. ]
[4.5 8.8]]
```

Annotations are mandatory to indicate inputs and outputs type. The decorator returns a function which is strict about types as opposed to numpy. This approach is similar to what tensorflow with autograph.

## Signatures¶

`mlprodict.npy.NDArray`

(*self*, *args*, *kwargs*)

`mlprodict.npy.NDArraySameType`

(*self*, *dtypes* = None)

Shortcut to simplify signature description.

`mlprodict.npy.NDArraySameTypeSameShape`

(*self*, *dtypes* = None)

Shortcut to simplify signature description.

`mlprodict.npy.onnx_numpy_annotation.NDArrayType`

(*self*, *dtypes* = None, *dtypes_out* = None, *n_optional* = None, *nvars* = False)

Shortcut to simplify signature description.

`mlprodict.npy.onnx_numpy_annotation.NDArrayTypeSameShape`

(*self*, *dtypes* = None, *dtypes_out* = None, *n_optional* = None, *nvars* = False)

Shortcut to simplify signature description.

## Decorators¶

`mlprodict.npy.onnxnumpy`

(*op_version* = None, *runtime* = None, *signature* = None)

`mlprodict.npy.onnxnumpy_default`

(*fct*)

`mlprodict.npy.onnxnumpy_np`

(*op_version* = None, *runtime* = None, *signature* = None)

`mlprodict.npy.onnxsklearn_class`

(*method_name*, *op_version* = None, *runtime* = None, *signature* = None, *method_names* = None, *overwrite* = True)

Decorator to declare a converter for a class derivated from scikit-learn, implementing inference method and using numpy syntax but executed with ONNX operators.

`mlprodict.npy.onnxsklearn_classifier`

(*op_version* = None, *runtime* = None, *signature* = None, *register_class* = None, *overwrite* = True)

`mlprodict.npy.onnxsklearn_cluster`

(*op_version* = None, *runtime* = None, *signature* = None, *register_class* = None, *overwrite* = True)

`mlprodict.npy.onnxsklearn_regressor`

(*op_version* = None, *runtime* = None, *signature* = None, *register_class* = None, *overwrite* = True)

`mlprodict.npy.onnxsklearn_transformer`

(*op_version* = None, *runtime* = None, *signature* = None, *register_class* = None, *overwrite* = True)

## OnnxNumpyCompiler¶

`mlprodict.npy.OnnxNumpyCompiler`

(*self*, *fct*, *op_version* = None, *runtime* = None, *signature* = None, *version* = None, *fctsig* = None)

Implements a class which runs onnx graph.

`mlprodict.npy.onnx_version.FctVersion`

(*self*, *args*, *kwargs*)

Identifies a version of a function based on its arguments and its parameters.

`as_string`

(self)Returns a single stirng identifier.

`as_tuple`

(self)Returns a single tuple for the version.

`as_tuple_with_sep`

(self,sep)Returns a single tuple for the version.

## OnnxVar¶

`mlprodict.npy.onnx_variable.OnnxVar`

(*self*, *inputs*, *op* = None, *select_output* = None, *dtype* = None, *kwargs*)

Variables used into onnx computation.

`astype`

(self,dtype)Cast

`copy`

(self)Returns a copy of self (use of Identity node).

`flatten`

(self,axis= 0)Flattens a matrix (see numpy.ndarray.flatten).

`not_`

(self)Not.

`reshape`

(self,shape)Reshape

`set_onnx_name`

(self,name_type)Forces this variable to get this name during

`to_algebra`

(self,op_version= None)Converts the variable into an operator.

`mlprodict.npy.onnx_variable.MultiOnnxVar`

(*self*, *inputs*, *op* = None, *dtype* = None, *kwargs*)

Class used to return multiple

`OnnxVar`

at the same time.

`to_algebra`

(self,op_version= None)Converts the variable into an operator.

`mlprodict.npy.onnx_variable.TupleOnnxAny`

(*self*, *first*, *args*)

Class used to return multiple

`OnnxVar`

at the same time.

`add_to`

(self,scope,container,operator= None,run_converters= False)Adds outputs to the container if not already added, registered the outputs if the node is not final.

`get_output_type_inference`

(self,input_shapes= None)Returns the expected output types in a list.

`to_onnx`

(self,args,kwargs)Converts the underlying class into an ONNX graph.

## Registration¶

`mlprodict.npy.update_registered_converter_npy`

(*model*, *alias*, *convert_fct*, *shape_fct* = None, *overwrite* = True, *parser* = None, *options* = None)

Registers or updates a converter for a new model so that it can be converted when inserted in a

scikit-learnpipeline. This function assumes the converter is written as a function decoarated with`onnxsklearn_transformer`

.

## Available functions implemented with ONNX operators¶

All functions are implemented in two submodules:

*numpy function*: module npy.numpy_onnx_impl*machine learned models:*module npy.numpy_onnx_impl_skl

## ONNX functions executed python ONNX runtime¶

Same function as above, the import goes from
`from mlprodict.npy.numpy_onnx_impl import <function-name>`

to
`from mlprodict.npy.numpy_onnx_pyrt import <function-name>`

.
These function are usually not used except in unit test or as
reference for more complex functions. See the source on github,
numpy_onnx_pyrt.py
and numpy_onnx_pyrt_skl.py.