1 files changed, 0 insertions, 119 deletions
diff --git a/experiments/hilbert_qr.cpp b/experiments/hilbert_qr.cpp
deleted file mode 100644
index 3a52194..0000000
--- a/experiments/hilbert_qr.cpp
+++ /dev/null
@@ -1,119 +0,0 @@
-import linalgebra;
-import std;
-
-using linalgebra::Matrix;
-using linalgebra::QRResult;
-
-Matrix hilbert(std::size_t n) {
-    Matrix H(n, n);
-    for (std::size_t i = 0; i < n; ++i)
-        for (std::size_t j = 0; j < n; ++j)
-            H(i, j) = 1.0 / static_cast<double>(i + j + 1);
-    return H;
-}
-
-double reconstruction_error(const Matrix& A, const QRResult& qr) {
-    const std::size_t m = A.rows();
-    const std::size_t n = A.cols();
-    const Matrix QR = qr.Q * qr.R;
-    double err = 0.0;
-    for (std::size_t i = 0; i < m; ++i)
-        for (std::size_t j = 0; j < n; ++j) {
-            const double d = A(i, j) - QR(i, j);
-            err += d * d;
-        }
-    return std::sqrt(err);
-}
-
-double orthogonality_error(const QRResult& qr) {
-    const Matrix& Q = qr.Q;
-    const std::size_t n = Q.cols();
-    double err = 0.0;
-    for (std::size_t i = 0; i < n; ++i)
-        for (std::size_t j = 0; j < n; ++j) {
-            double s = 0.0;
-            for (std::size_t k = 0; k < Q.rows(); ++k) s += Q(k, i) * Q(k, j);
-            const double d = s - (i == j ? 1.0 : 0.0);
-            err += d * d;
-        }
-    return std::sqrt(err);
-}
-
-using Clock = std::chrono::high_resolution_clock;
-using Seconds = std::chrono::duration<double>;
-
-template<typename Fn>
-double min_time(Fn fn, int trials = 5) {
-    double best = 1e18;
-    for (int t = 0; t < trials; ++t) {
-        const auto t0 = Clock::now();
-        fn();
-        const auto t1 = Clock::now();
-        best = std::min(best, Seconds(t1 - t0).count());
-    }
-    return best;
-}
-
-using QRFn = std::function<QRResult(const Matrix&)>;
-
-struct Result { double recon, ortho, time_s; };
-
-std::optional<Result> measure(const Matrix& A, QRFn fn) {
-    try {
-        const QRResult qr = fn(A);
-        const double re = reconstruction_error(A, qr);
-        const double oe = orthogonality_error(qr);
-        const double t = min_time([&] { fn(A); });
-        return Result{re, oe, t};
-    } catch (const std::exception&) {
-        return std::nullopt;
-    }
-}
-
-void print_row(const std::string& method, std::optional<Result> r) {
-    std::cout << std::left << std::setw(16) << method;
-    if (!r) {
-        std::cout << "  FAILED (linearly dependent columns)\n";
-        return;
-    }
-    std::cout << std::scientific << std::setprecision(2)
-              << std::setw(14) << r->recon
-              << std::setw(14) << r->ortho
-              << std::fixed << std::setprecision(3)
-              << std::setw(10) << r->time_s * 1e6 << " µs\n";
-}
-
-int main() {
-    std::cout << std::string(70, '*') << "\n";
-    std::cout << "  Hilbert QR Experiment: comparing GS variants and Householder\n";
-    std::cout << std::string(70, '*') << "\n\n";
-    std::cout <<
-        "H[i][j] = 1/(i+j+1). Condition number grows ~exponentially with n.\n"
-        "Orthogonality loss in classical GS tracks condition number directly.\n"
-        "Modified GS recovers ~half the lost digits. Householder is unaffected.\n\n";
-
-    const std::size_t sizes[] = {2, 3, 4, 5, 6, 7, 8, 10, 12};
-
-    for (std::size_t n : sizes) {
-        const Matrix H = hilbert(n);
-
-        std::cout << std::string(70, '-') << "\n";
-        std::cout << "  n = " << n << "\n";
-        std::cout << std::string(70, '-') << "\n";
-        std::cout << std::left
-                  << std::setw(16) << "Method"
-                  << std::setw(14) << "||A-QR||_F"
-                  << std::setw(14) << "||QtQ-I||_F"
-                  << std::setw(10) << "Time\n";
-        std::cout << std::string(70, ' ') << "\n";
-
-        print_row("classical_gs",
-            measure(H, [](const Matrix& A) { return linalgebra::qr_classical_gs(A); }));
-        print_row("modified_gs",
-            measure(H, [](const Matrix& A) { return linalgebra::qr_modified_gs(A); }));
-        print_row("householder",
-            measure(H, [](const Matrix& A) { return linalgebra::qr_householder(A); }));
-    }
-
-    return 0;
-}