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feat(PolyEqvSpline), perf: Changed polynomial shift algorithm #70

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Merged
pasabanov merged 1 commit into from
Apr 30, 2025
Merged

feat(PolyEqvSpline), perf: Changed polynomial shift algorithm #70

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37 changes: 13 additions & 24 deletions ALFI/ALFI/spline/polyeqv.h
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Original file line number Diff line number Diff line change
Expand Up @@ -90,33 +90,17 @@ namespace alfi::spline {
case PolynomialType::IMPROVED_LAGRANGE: P = poly::imp_lagrange(X, Y); break;
case PolynomialType::NEWTON: P = poly::newton(X, Y); break;
}

const static auto binomials = [](SizeT m) {
Container<Container<Number>> C(m + 1);
for (SizeT i = 0; i <= m; ++i) {
C[i].resize(i + 1);
C[i][0] = C[i][i] = 1;
for (SizeT j = 1; j <= i / 2; ++j) {
C[i][j] = C[i][i-j] = C[i-1][j-1] + C[i-1][j];
}
}
return C;
};

const auto C = binomials(n - 1);

#if defined(_OPENMP) && !defined(ALFI_DISABLE_OPENMP)
#pragma omp parallel for
#endif
for (SizeT i = 0; i < n - 1; ++i) {
coeffs[i*n] = P[0];
for (SizeT k = 1; k < n - 1; ++k) {
Number r = 0;
for (SizeT j = 0; j < k; ++j) {
r += ((((k - j) & 1) == 0) ? 1 : -1) * coeffs[i*n+j] * C[n-1-j][k-j];
r *= X[i];
for (SizeT j = 0; j < n; ++j) {
coeffs[i*n+j] = P[j];
}
for (SizeT k = 0; k < n - 1; ++k) {
for (SizeT j = 1; j < n - k; ++j) {
coeffs[i*n+j] += coeffs[i*n+j-1] * X[i];
}
coeffs[i*n+k] = P[k] - r;
}
coeffs[i*n+n-1] = Y[i];
}
Expand All @@ -128,12 +112,17 @@ namespace alfi::spline {

PolyEqvSpline() = default;

template <typename ContainerXType>
PolyEqvSpline(ContainerXType&& X, const Container<Number>& Y, OptimizationType optimization_type)
: PolyEqvSpline(std::forward<ContainerXType>(X), Y, PolynomialType::Default, optimization_type) {}

template <typename ContainerXType>
PolyEqvSpline(ContainerXType&& X,
const Container<Number>& Y,
PolynomialType polynomial_type = PolynomialType::Default,
OptimizationType optimization_type = OptimizationType::Default) {
construct(std::forward<ContainerXType>(X), Y, polynomial_type, optimization_type);
OptimizationType optimization_type = OptimizationType::Default,
EvaluationType evaluation_type = EvaluationType::Default) {
construct(std::forward<ContainerXType>(X), Y, polynomial_type, optimization_type, evaluation_type);
}

PolyEqvSpline(const PolyEqvSpline& other) = default;
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7 changes: 4 additions & 3 deletions tests/spline/test_polyeqv.cpp
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Expand Up @@ -6,7 +6,7 @@ const auto test_data_path = TEST_DATA_DIR "/poly/poly.toml";

const auto test_data = toml::parse_file(test_data_path);

void test_polyeqv_spline(double epsilon) {
void test_polyeqv_spline(double epsilon_accuracy, double epsilon_speed) {
const auto& test_cases = test_data["test_cases"].ref<toml::array>();

test_cases.for_each([&](const toml::table& test_case) {
Expand All @@ -15,12 +15,13 @@ void test_polyeqv_spline(double epsilon) {
const auto& xx = to_vector<double>(test_case["xx"].ref<toml::array>());
const auto& yy = to_vector<double>(test_case["yy"].ref<toml::array>());

expect_eq(alfi::spline::PolyEqvSpline<>(X, Y).eval(xx), yy, epsilon);
expect_eq(alfi::spline::PolyEqvSpline<>(X, Y, alfi::spline::PolyEqvSpline<>::OptimizationType::ACCURACY).eval(xx), yy, epsilon_accuracy);
expect_eq(alfi::spline::PolyEqvSpline<>(X, Y, alfi::spline::PolyEqvSpline<>::OptimizationType::SPEED).eval(xx), yy, epsilon_speed);
});
}

TEST(PolyEqvSplineTest, PolynomialData) {
test_polyeqv_spline(1e-10);
test_polyeqv_spline(1e-10, 1e-2);
}

TEST(PolyEqvSplineTest, General) {
Expand Down