test_stringkernels.py

"""Test String-Kernel based models."""
import numpy as np
from numpy.testing import assert_array_equal
from tuhlbox.stringkernels import (intersection_kernel, presence_kernel,
                                   spectrum_kernel, legacy_intersection_kernel,
                                   legacy_spectrum_kernel, legacy_presence_kernel)

docs = [
    "I like this old movie. The movie is very nice.",
    "In my opinion the book tells a very nice story. I really like it.",
    "I wonder if you could drink this juice. It tastes so bad. Isn’t it bad?",
    "Your dish is too spicy. You must be a such bad cook. "
    "Don’t worry, I am as bad as you.",
]

ngram_min, ngram_max = 1, 4


def test_intersection_kernel() -> None:
    """Test intersection kernel by comparing with original code."""
    # obtained from:
    # java ComputeStringKernel intersection 1 4 sentences.txt <outfile>
    expected = np.array(
        [[178, 95, 66, 49], [95, 254, 72, 72], [66, 72, 278, 112], [49, 72, 112, 334]],
        dtype=int,
    )
    assert_array_equal(expected, intersection_kernel(ngram_min, ngram_max)(docs, docs))


def test_legacy_intersection_kernel() -> None:
    """Test intersection kernel by comparing with original code."""
    # obtained from:
    # java ComputeStringKernel intersection 1 4 sentences.txt <outfile>
    expected = np.array(
        [[178, 95, 66, 49], [95, 254, 72, 72], [66, 72, 278, 112], [49, 72, 112, 334]],
        dtype=int,
    )
    actual = legacy_intersection_kernel(ngram_min, ngram_max)(docs, docs)
    assert_array_equal(expected, actual)


def test_presence_kernel() -> None:
    """Test presence kernel by comparing with original code."""
    # obtained from:
    # java ComputeStringKernel presence 1 4 sentences.txt <outfile>

    expected = np.array(
        [[128, 67, 42, 29], [67, 197, 38, 42], [42, 38, 209, 64], [29, 42, 64, 235]],
        dtype=int,
    )
    assert_array_equal(expected, presence_kernel(ngram_min, ngram_max)(docs, docs))


def test_legacy_presence_kernel() -> None:
    """Test presence kernel by comparing with original code."""
    # obtained from:
    # java ComputeStringKernel presence 1 4 sentences.txt <outfile>

    expected = np.array(
        [[128, 67, 42, 29], [67, 197, 38, 42], [42, 38, 209, 64], [29, 42, 64, 235]],
        dtype=int,
    )
    assert_array_equal(expected, legacy_presence_kernel(ngram_min, ngram_max)(docs, docs))



def test_spectrum_kernel() -> None:
    """Test spectrum kernel by comparing with original code."""
    # obtained from:
    # java ComputeStringKernel spectrum 1 4 sentences.txt <outfile>
    expected = np.array(
        [
            [390, 335, 300, 313],
            [335, 598, 393, 458],
            [300, 393, 680, 585],
            [313, 458, 585, 1006],
        ],
        dtype=int,
    )
    assert_array_equal(expected, spectrum_kernel(ngram_min, ngram_max)(docs, docs))


def test_legacy_spectrum_kernel() -> None:
    """Test spectrum kernel by comparing with original code."""
    # obtained from:
    # java ComputeStringKernel spectrum 1 4 sentences.txt <outfile>
    expected = np.array(
        [
            [390, 335, 300, 313],
            [335, 598, 393, 458],
            [300, 393, 680, 585],
            [313, 458, 585, 1006],
        ],
        dtype=int,
    )
    assert_array_equal(expected, legacy_spectrum_kernel(ngram_min, ngram_max)(docs, docs))