.. blogpost::
    :title: Convert a Lightgbm dump
    :keywords: ONNX, lightgbm, onnxmltools
    :date: 2021-07-09
    :categories: converters

    This example shows how to convert a :epkg:`lightgbm` model
    dumped as a text file. It uses :epkg:`lightgbm` to restore
    the model, converts it and checks the discrepencies.

    ::

        import numpy
        from numpy.testing import assert_almost_equal
        import lightgbm
        from onnxruntime import InferenceSession
        from onnxmltools import convert_lightgbm
        from skl2onnx.common.data_types import FloatTensorType

        booster = lightgbm.Booster(model_file="model.txt")
        n = booster.num_feature()

        onx = convert_lightgbm(booster, initial_types=[('input', FloatTensorType([None, n]))])

        sess = InferenceSession(onx.SerializeToString())
        rnd = numpy.random.random((1, n)).astype(numpy.float32)

        expected = booster.predict(rnd)
        got = sess.run(None, {'input': rnd})[0]

        assert_almost_equal(expected, got.ravel(), decimal=4)