mlprodict¶
Links: github, documentation, mlprodict, blog
mlprodict explores couple of ways to compute predictions faster than the library used to build the machine learned model, mostly scikit-learn which is optimized for training, which is equivalent to batch predictions. One way is to use ONNX. onnxruntime provides an efficient way to compute predictions. The current code explores ways to be faster at implementing something working and provides a python runtime for ONNX.
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from sklearn.linear_model import LinearRegression
from sklearn.datasets import load_iris
from mlprodict.onnxrt import OnnxInference, measure_relative_difference
import numpy
iris = load_iris()
X = iris.data[:, :2]
y = iris.target
lr = LinearRegression()
lr.fit(X, y)
# Predictions with scikit-learn.
expected = lr.predict(X[:5])
print(expected)
# Conversion into ONNX.
from skl2onnx import to_onnx
model_onnx = to_onnx(lr, X.astype(numpy.float32))
print("ONNX:", str(model_onnx)[:200] + "\n...")
# Predictions with onnxruntime
oinf = OnnxInference(model_onnx, runtime='onnxruntime1')
ypred = oinf.run({'X': X[:5].astype(numpy.float32)})
print("ONNX output:", ypred)
# Measuring the maximum difference.
print("max abs diff:", measure_relative_difference(
expected, ypred['variable']))
>>>
[0.172 0.343 0.069 0.059 0.034]
ONNX: ir_version: 5
producer_name: "skl2onnx"
producer_version: "1.5.9999"
domain: "ai.onnx"
model_version: 0
doc_string: ""
graph {
node {
input: "X"
output: "variable"
name: "LinearRegressor
...
ONNX output: {'variable': array([[0.172],
[0.343],
[0.069],
[0.059],
[0.034]], dtype=float32)}
max abs diff: 6.303014714402957e-06
These predictions are obtained with the following ONNX graph.
Notebook ONNX visualization shows how to visualize an ONNX pipeline. Another way is to convert the prediction function into C.
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from sklearn.linear_model import LogisticRegression
from sklearn.datasets import load_iris
iris = load_iris()
X = iris.data[:, :2]
y = iris.target
y[y == 2] = 1
lr = LogisticRegression()
lr.fit(X, y)
# Conversion into a graph.
from mlprodict.grammar_sklearn import sklearn2graph
gr = sklearn2graph(lr, output_names=['Prediction', 'Score'])
# Conversion into C
ccode = gr.export(lang='c')
# We print after a little bit of cleaning (remove all comments)
print("\n".join(_ for _ in ccode['code'].split("\n") if "//" not in _))
>>>
int LogisticRegression (float* pred, float* Features)
{
float pred0c0c00c0[2] = {(float)3.3882975578308105, (float)-3.164527654647827};
float* pred0c0c00c1 = Features;
float pred0c0c00;
adot_float_float(&pred0c0c00, pred0c0c00c0, pred0c0c00c1, 2);
float pred0c0c01 = (float)-8.323304176330566;
float pred0c0c0 = pred0c0c00 + pred0c0c01;
float pred0c0;
sign_float(&pred0c0, pred0c0c0);
float pred0[2];
concat_float_float(pred0, pred0c0, pred0c0c0);
memcpy(pred, pred0, 2*sizeof(float));
return 0;
}
