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https://gitlab.com/libeigen/eigen.git
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677 lines
24 KiB
C++
677 lines
24 KiB
C++
// Standalone tool to measure ULP accuracy of Eigen's vectorized math functions
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// against either MPFR (high-precision reference) or std C++ math functions.
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//
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// See README.md in this directory for full documentation.
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//
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// Usage:
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// ./ulp_accuracy --func=sin --lo=0 --hi=6.2832 --threads=16
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// ./ulp_accuracy --func=exp --threads=16
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// ./ulp_accuracy --func=sin --ref=mpfr
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// ./ulp_accuracy --func=sin --double --step=1e-6
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// ./ulp_accuracy --list
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//
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// Build:
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// cd build && cmake .. && make ulp_accuracy
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#include <Eigen/Core>
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#include <unsupported/Eigen/SpecialFunctions>
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#ifdef EIGEN_HAS_MPFR
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#include <mpfr.h>
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#endif
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#include <atomic>
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#include <cfloat>
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#include <chrono>
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#include <cmath>
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#include <cstdint>
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#include <cstdio>
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#include <cstring>
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#include <functional>
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#include <limits>
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#include <memory>
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#include <string>
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#include <thread>
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#include <type_traits>
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#include <vector>
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#include "mpfr_reference.h"
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// ============================================================================
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// ULP distance computation
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// ============================================================================
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// Maps IEEE 754 bits to a linear integer scale where adjacent representable
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// values are adjacent integers. The mapping is strictly monotonic:
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// -inf -> most negative, -0.0 -> -1, +0.0 -> 0, +inf -> most positive.
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static inline int64_t scalar_to_linear(float x) {
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int32_t bits;
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std::memcpy(&bits, &x, sizeof(bits));
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if (bits < 0) {
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bits = static_cast<int32_t>(INT32_MIN) - bits - 1;
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}
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return static_cast<int64_t>(bits);
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}
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static inline int64_t scalar_to_linear(double x) {
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int64_t bits;
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std::memcpy(&bits, &x, sizeof(bits));
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if (bits < 0) {
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bits = static_cast<int64_t>(INT64_MIN) - bits - 1;
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}
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return bits;
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}
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// Returns (eigen_val - ref_val) in ULP space.
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// Positive means Eigen overestimates, negative means it underestimates.
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// Returns INT64_MAX for incomparable values (NaN vs number, inf mismatch).
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template <typename Scalar>
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static inline int64_t signed_ulp_error(Scalar eigen_val, Scalar ref_val) {
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if (eigen_val == ref_val) return 0; // also handles -0.0 == +0.0
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bool e_nan = std::isnan(eigen_val), r_nan = std::isnan(ref_val);
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if (e_nan && r_nan) return 0;
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if (e_nan || r_nan) return INT64_MAX;
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if (std::isinf(eigen_val) || std::isinf(ref_val)) return INT64_MAX;
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int64_t a = scalar_to_linear(eigen_val);
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int64_t b = scalar_to_linear(ref_val);
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// Overflow check for a - b.
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if (b > 0 && a < INT64_MIN + b) return INT64_MAX;
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if (b < 0 && a > INT64_MAX + b) return INT64_MAX;
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return a - b;
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}
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// ============================================================================
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// Per-thread accumulator with signed ULP histogram
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// ============================================================================
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template <typename Scalar>
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struct ThreadResult {
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int64_t max_abs_ulp = 0;
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Scalar max_ulp_at = Scalar(0);
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Scalar max_ulp_eigen = Scalar(0);
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Scalar max_ulp_ref = Scalar(0);
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double abs_ulp_sum = 0.0;
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uint64_t count = 0;
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// Signed histogram: bins for errors in [-hist_width, +hist_width],
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// plus two overflow bins for < -hist_width and > +hist_width.
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// Layout: [<-W] [-W] [-W+1] ... [0] ... [W-1] [W] [>W]
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// Total bins = 2*hist_width + 3
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int hist_width = 0;
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std::vector<uint64_t> hist;
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void init(int w) {
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hist_width = w;
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hist.assign(2 * w + 3, 0);
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}
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void record(int64_t signed_err, Scalar x, Scalar eigen_val, Scalar ref_val) {
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int64_t abs_err = signed_err < 0 ? -signed_err : signed_err;
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if (signed_err == INT64_MAX) abs_err = INT64_MAX;
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if (abs_err > max_abs_ulp) {
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max_abs_ulp = abs_err;
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max_ulp_at = x;
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max_ulp_eigen = eigen_val;
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max_ulp_ref = ref_val;
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}
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if (abs_err != INT64_MAX) {
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abs_ulp_sum += static_cast<double>(abs_err);
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}
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count++;
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// Histogram bin.
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int bin;
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if (signed_err == INT64_MAX || signed_err > hist_width) {
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bin = 2 * hist_width + 2; // overflow high
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} else if (signed_err < -hist_width) {
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bin = 0; // overflow low
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} else {
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bin = static_cast<int>(signed_err) + hist_width + 1;
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}
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hist[bin]++;
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}
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};
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// ============================================================================
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// Function registry
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// ============================================================================
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template <typename Scalar>
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struct FuncEntry {
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using ArrayType = Eigen::Array<Scalar, Eigen::Dynamic, 1>;
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using EigenEval = std::function<void(Eigen::Ref<ArrayType>, const Eigen::Ref<const ArrayType>&)>;
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using StdEval = std::function<Scalar(Scalar)>;
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#ifdef EIGEN_HAS_MPFR
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using MpfrEval = std::function<int(mpfr_t, const mpfr_t, mpfr_rnd_t)>;
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#endif
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std::string name;
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EigenEval eigen_eval;
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StdEval std_eval;
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#ifdef EIGEN_HAS_MPFR
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MpfrEval mpfr_eval;
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#endif
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Scalar default_lo;
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Scalar default_hi;
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};
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// std::logistic is not part of the C++ standard library.
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template <typename Scalar>
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static Scalar std_logistic(Scalar x) {
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if (x >= 0) {
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Scalar e = std::exp(-x);
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return Scalar(1) / (Scalar(1) + e);
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} else {
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Scalar e = std::exp(x);
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return e / (Scalar(1) + e);
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}
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}
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template <typename Scalar>
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static std::vector<FuncEntry<Scalar>> build_func_table() {
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using ArrayType = Eigen::Array<Scalar, Eigen::Dynamic, 1>;
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std::vector<FuncEntry<Scalar>> table;
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#ifdef EIGEN_HAS_MPFR
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#define ADD_FUNC(fname, eigen_expr, std_expr, mpfr_fn, lo, hi) \
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table.push_back({#fname, [](Eigen::Ref<ArrayType> out, const Eigen::Ref<const ArrayType>& a) { out = eigen_expr; }, \
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[](Scalar x) -> Scalar { return std_expr; }, \
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[](mpfr_t r, const mpfr_t o, mpfr_rnd_t d) { return mpfr_fn(r, o, d); }, lo, hi})
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#else
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#define ADD_FUNC(fname, eigen_expr, std_expr, mpfr_fn, lo, hi) \
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table.push_back({#fname, [](Eigen::Ref<ArrayType> out, const Eigen::Ref<const ArrayType>& a) { out = eigen_expr; }, \
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[](Scalar x) -> Scalar { return std_expr; }, lo, hi})
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#endif
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constexpr Scalar kInf = std::numeric_limits<Scalar>::infinity();
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// Trigonometric
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// clang-format off
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ADD_FUNC(sin, a.sin(), std::sin(x), mpfr_sin, -kInf, kInf);
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ADD_FUNC(cos, a.cos(), std::cos(x), mpfr_cos, -kInf, kInf);
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ADD_FUNC(tan, a.tan(), std::tan(x), mpfr_tan, -kInf, kInf);
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ADD_FUNC(asin, a.asin(), std::asin(x), mpfr_asin, -kInf, kInf);
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ADD_FUNC(acos, a.acos(), std::acos(x), mpfr_acos, -kInf, kInf);
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ADD_FUNC(atan, a.atan(), std::atan(x), mpfr_atan, -kInf, kInf);
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// Hyperbolic
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ADD_FUNC(sinh, a.sinh(), std::sinh(x), mpfr_sinh, -kInf, kInf);
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ADD_FUNC(cosh, a.cosh(), std::cosh(x), mpfr_cosh, -kInf, kInf);
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ADD_FUNC(tanh, a.tanh(), std::tanh(x), mpfr_tanh, -kInf, kInf);
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ADD_FUNC(asinh, a.asinh(), std::asinh(x), mpfr_asinh, -kInf, kInf);
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ADD_FUNC(acosh, a.acosh(), std::acosh(x), mpfr_acosh, -kInf, kInf);
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ADD_FUNC(atanh, a.atanh(), std::atanh(x), mpfr_atanh, -kInf, kInf);
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// Exponential / Logarithmic
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ADD_FUNC(exp, a.exp(), std::exp(x), mpfr_exp, -kInf, kInf);
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ADD_FUNC(exp2, a.exp2(), std::exp2(x), mpfr_exp2_wrap, -kInf, kInf);
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ADD_FUNC(expm1, a.expm1(), std::expm1(x), mpfr_expm1, -kInf, kInf);
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ADD_FUNC(log, a.log(), std::log(x), mpfr_log, -kInf, kInf);
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ADD_FUNC(log1p, a.log1p(), std::log1p(x), mpfr_log1p, -kInf, kInf);
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ADD_FUNC(log10, a.log10(), std::log10(x), mpfr_log10, -kInf, kInf);
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ADD_FUNC(log2, a.log2(), std::log2(x), mpfr_log2_wrap, -kInf, kInf);
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// Error / Gamma
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ADD_FUNC(erf, a.erf(), std::erf(x), mpfr_erf, -kInf, kInf);
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ADD_FUNC(erfc, a.erfc(), std::erfc(x), mpfr_erfc, -kInf, kInf);
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ADD_FUNC(lgamma, a.lgamma(), std::lgamma(x), mpfr_lngamma, -kInf, kInf);
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// Other
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ADD_FUNC(logistic, a.logistic(), std_logistic(x), mpfr_logistic, -kInf, kInf);
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ADD_FUNC(sqrt, a.sqrt(), std::sqrt(x), mpfr_sqrt, -kInf, kInf);
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ADD_FUNC(cbrt, a.cbrt(), std::cbrt(x), mpfr_cbrt, -kInf, kInf);
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ADD_FUNC(rsqrt, a.rsqrt(), Scalar(1)/std::sqrt(x), mpfr_rsqrt, -kInf, kInf);
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// clang-format on
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#undef ADD_FUNC
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return table;
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}
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// ============================================================================
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// Range iteration helpers
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// ============================================================================
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// Advances a non-negative value toward +inf by at least 1 ULP. When step_eps > 0,
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// additionally jumps by max(|x|, min_normal) * step_eps. For normals this is
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// equivalent to x * (1 + eps). For denormals where x * eps < smallest_denormal,
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// the min_normal floor ensures we still skip through the denormal region at a
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// rate matching the smallest normals rather than stalling at 1 ULP per step.
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template <typename Scalar>
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static inline Scalar advance_positive(Scalar x, double step_eps) {
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Scalar next = std::nextafter(x, std::numeric_limits<Scalar>::infinity());
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if (step_eps > 0.0 && std::isfinite(next)) {
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Scalar base = std::max(next, std::numeric_limits<Scalar>::min());
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Scalar jumped = next + base * static_cast<Scalar>(step_eps);
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if (jumped > next) next = jumped;
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}
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return next;
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}
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// Counts the number of representable scalars in [lo, hi].
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template <typename Scalar>
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static uint64_t count_scalars_in_range(Scalar lo, Scalar hi) {
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if (lo > hi) return 0;
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uint64_t lo_u = static_cast<uint64_t>(scalar_to_linear(lo));
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uint64_t hi_u = static_cast<uint64_t>(scalar_to_linear(hi));
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uint64_t diff = hi_u - lo_u;
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return diff == UINT64_MAX ? UINT64_MAX : diff + 1;
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}
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// ============================================================================
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// Inverse of scalar_to_linear: maps a linear integer back to a scalar.
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// ============================================================================
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static float linear_to_scalar(int64_t lin, float /*tag*/) {
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int32_t ibits = static_cast<int32_t>(lin);
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if (ibits < 0) ibits = static_cast<int32_t>(INT32_MIN) - ibits - 1;
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float result;
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std::memcpy(&result, &ibits, sizeof(result));
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return result;
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}
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static double linear_to_scalar(int64_t lin, double /*tag*/) {
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int64_t ibits = lin;
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if (ibits < 0) ibits = static_cast<int64_t>(INT64_MIN) - ibits - 1;
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double result;
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std::memcpy(&result, &ibits, sizeof(result));
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return result;
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}
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// ============================================================================
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// Dynamic work queue: threads atomically claim chunks for load balancing
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// ============================================================================
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// Work queue that distributes chunks in positive absolute-value linear space.
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// Iteration goes outward from 0: the worker tests both +|x| and -|x| for
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// each sampled magnitude, so the multiplicative step (1 + eps) always works
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// cleanly — no special handling for negative values needed.
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template <typename Scalar>
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struct WorkQueue {
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int64_t range_hi_lin;
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int64_t chunk_size;
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double step_eps;
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std::atomic<int64_t> next_lin;
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Scalar orig_lo; // original range for sign filtering
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Scalar orig_hi;
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bool test_pos; // whether any positive values are in [lo, hi]
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bool test_neg; // whether any negative values are in [lo, hi]
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void init(Scalar lo, Scalar hi, int num_threads, double step) {
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orig_lo = lo;
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orig_hi = hi;
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test_pos = (hi >= Scalar(0));
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test_neg = (lo < Scalar(0));
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// Compute absolute-value iteration range.
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Scalar abs_lo, abs_hi;
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if (lo <= Scalar(0) && hi >= Scalar(0)) {
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abs_lo = Scalar(0);
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abs_hi = std::max(std::abs(lo), hi);
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} else {
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abs_lo = std::min(std::abs(lo), std::abs(hi));
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abs_hi = std::max(std::abs(lo), std::abs(hi));
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}
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range_hi_lin = scalar_to_linear(abs_hi);
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step_eps = step;
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next_lin.store(scalar_to_linear(abs_lo), std::memory_order_relaxed);
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uint64_t total_abs = count_scalars_in_range(abs_lo, abs_hi);
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chunk_size = std::max(int64_t(1), static_cast<int64_t>(total_abs / (num_threads * 16)));
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if (step > 0.0) {
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// Ensure chunks are large enough that advance_positive's min_normal floor
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// can actually skip the denormal region. The denormal region contains
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// count_scalars_in_range(0, min_normal) ULPs; any chunk must span at
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// least that many so the min_normal-based jump lands past chunk_hi.
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int64_t denorm_span = static_cast<int64_t>(count_scalars_in_range(Scalar(0), std::numeric_limits<Scalar>::min()));
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chunk_size = std::max(chunk_size, denorm_span);
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}
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}
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// Claim the next chunk of absolute values. Returns false when no work remains.
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bool claim(Scalar& chunk_lo, Scalar& chunk_hi) {
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int64_t lo_lin = next_lin.fetch_add(chunk_size, std::memory_order_relaxed);
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if (lo_lin > range_hi_lin || lo_lin < 0) return false;
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// Compute hi_lin carefully to avoid int64_t overflow.
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int64_t remaining = range_hi_lin - lo_lin;
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int64_t hi_lin = (remaining < chunk_size - 1) ? range_hi_lin : lo_lin + chunk_size - 1;
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chunk_lo = linear_to_scalar(lo_lin, Scalar(0));
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chunk_hi = linear_to_scalar(hi_lin, Scalar(0));
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return true;
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}
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};
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// ============================================================================
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// Worker thread: dynamically claims chunks from a shared work queue
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// ============================================================================
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template <typename Scalar>
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static void worker(const FuncEntry<Scalar>& func, WorkQueue<Scalar>& queue, int batch_size, bool use_mpfr,
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ThreadResult<Scalar>& result) {
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using ArrayType = Eigen::Array<Scalar, Eigen::Dynamic, 1>;
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ArrayType input(batch_size);
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ArrayType eigen_out(batch_size);
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std::vector<Scalar> ref_out(batch_size);
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#ifdef EIGEN_HAS_MPFR
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mpfr_t mp_in, mp_out;
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if (use_mpfr) {
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// Use 2x the mantissa bits of Scalar for the reference: 48 for float (24-bit
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// mantissa), 106 for double (53-bit mantissa). This is sufficient for correctly-
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// rounded results while keeping MPFR evaluation fast.
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constexpr int kMpfrBits = std::is_same<Scalar, float>::value ? 48 : 106;
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mpfr_init2(mp_in, kMpfrBits);
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mpfr_init2(mp_out, kMpfrBits);
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}
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#else
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(void)use_mpfr;
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#endif
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auto process_batch = [&](int n, const ArrayType& in, const ArrayType& eig) {
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for (int i = 0; i < n; i++) {
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#ifdef EIGEN_HAS_MPFR
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if (use_mpfr) {
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mpfr_set_scalar<Scalar>(mp_in, in[i], MPFR_RNDN);
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func.mpfr_eval(mp_out, mp_in, MPFR_RNDN);
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ref_out[i] = mpfr_get_scalar<Scalar>(mp_out, MPFR_RNDN);
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} else
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#endif
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{
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ref_out[i] = func.std_eval(in[i]);
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}
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}
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for (int i = 0; i < n; i++) {
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int64_t err = signed_ulp_error(eig[i], ref_out[i]);
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result.record(err, in[i], eig[i], ref_out[i]);
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}
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};
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auto flush_batch = [&](int& idx) {
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if (idx == 0) return;
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for (int i = idx; i < batch_size; i++) input[i] = input[idx - 1];
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func.eigen_eval(eigen_out, input);
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process_batch(idx, input, eigen_out);
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idx = 0;
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};
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auto push_value = [&](Scalar v, int& idx) {
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input[idx++] = v;
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if (idx == batch_size) flush_batch(idx);
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};
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Scalar chunk_lo, chunk_hi;
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while (queue.claim(chunk_lo, chunk_hi)) {
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int idx = 0;
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Scalar abs_x = chunk_lo;
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for (;;) {
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// Test +|x| if positive values are in range.
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if (queue.test_pos && abs_x >= queue.orig_lo && abs_x <= queue.orig_hi) {
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push_value(abs_x, idx);
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}
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// Test -|x| if negative values are in range (skip -0 to avoid testing 0 twice).
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if (queue.test_neg && abs_x != Scalar(0)) {
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Scalar neg_x = -abs_x;
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if (neg_x >= queue.orig_lo && neg_x <= queue.orig_hi) {
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push_value(neg_x, idx);
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}
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}
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if (abs_x >= chunk_hi) break;
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Scalar next = advance_positive(abs_x, queue.step_eps);
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abs_x = (next > chunk_hi) ? chunk_hi : next;
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}
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flush_batch(idx);
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}
|
|
|
|
#ifdef EIGEN_HAS_MPFR
|
|
if (use_mpfr) {
|
|
mpfr_clear(mp_in);
|
|
mpfr_clear(mp_out);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
// ============================================================================
|
|
// Test driver: splits range across threads and prints results
|
|
// ============================================================================
|
|
|
|
struct Options {
|
|
std::string func_name;
|
|
double lo = std::numeric_limits<double>::quiet_NaN();
|
|
double hi = std::numeric_limits<double>::quiet_NaN();
|
|
int num_threads;
|
|
int batch_size = 4096;
|
|
int hist_width = 10;
|
|
bool use_mpfr = false;
|
|
bool use_double = false;
|
|
double step_eps = 0.0;
|
|
bool list_funcs = false;
|
|
};
|
|
|
|
template <typename Scalar>
|
|
static int run_test(const Options& opts) {
|
|
const int kDigits = std::is_same<Scalar, float>::value ? 9 : 17;
|
|
const char* kTypeName = std::is_same<Scalar, float>::value ? "float" : "double";
|
|
|
|
auto table = build_func_table<Scalar>();
|
|
|
|
if (opts.list_funcs) {
|
|
std::printf("Available functions:\n");
|
|
for (const auto& f : table) {
|
|
std::printf(" %s\n", f.name.c_str());
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
// Look up the requested function.
|
|
const FuncEntry<Scalar>* entry = nullptr;
|
|
for (const auto& f : table) {
|
|
if (f.name == opts.func_name) {
|
|
entry = &f;
|
|
break;
|
|
}
|
|
}
|
|
if (!entry) {
|
|
std::fprintf(stderr, "Error: unknown function '%s' (use --list to see available functions)\n",
|
|
opts.func_name.c_str());
|
|
return 1;
|
|
}
|
|
|
|
Scalar lo = std::isnan(opts.lo) ? entry->default_lo : static_cast<Scalar>(opts.lo);
|
|
Scalar hi = std::isnan(opts.hi) ? entry->default_hi : static_cast<Scalar>(opts.hi);
|
|
uint64_t total_scalars = count_scalars_in_range(lo, hi);
|
|
int num_threads = opts.num_threads;
|
|
|
|
// Print test configuration.
|
|
std::printf("Function: %s (%s)\n", opts.func_name.c_str(), kTypeName);
|
|
std::printf("Range: [%.*g, %.*g]\n", kDigits, double(lo), kDigits, double(hi));
|
|
if (opts.step_eps > 0.0) {
|
|
std::printf("Sampling step: |x| * (1 + %g)\n", opts.step_eps);
|
|
} else {
|
|
std::printf("Representable values in range: %lu\n", static_cast<unsigned long>(total_scalars));
|
|
}
|
|
std::printf("Reference: %s\n",
|
|
opts.use_mpfr ? (opts.use_double ? "MPFR (106-bit)" : "MPFR (48-bit)") : "std C++ math");
|
|
std::printf("Threads: %d\n", num_threads);
|
|
std::printf("Batch size: %d\n", opts.batch_size);
|
|
std::printf("\n");
|
|
std::fflush(stdout);
|
|
|
|
if (num_threads < 1) num_threads = 1;
|
|
|
|
// Heap-allocate each ThreadResult separately to avoid false sharing.
|
|
std::vector<std::unique_ptr<ThreadResult<Scalar>>> results;
|
|
results.reserve(num_threads);
|
|
for (int t = 0; t < num_threads; t++) {
|
|
results.push_back(std::make_unique<ThreadResult<Scalar>>());
|
|
results.back()->init(opts.hist_width);
|
|
}
|
|
|
|
WorkQueue<Scalar> queue;
|
|
queue.init(lo, hi, num_threads, opts.step_eps);
|
|
|
|
std::vector<std::thread> threads;
|
|
auto start_time = std::chrono::steady_clock::now();
|
|
|
|
for (int t = 0; t < num_threads; t++) {
|
|
threads.emplace_back(worker<Scalar>, std::cref(*entry), std::ref(queue), opts.batch_size, opts.use_mpfr,
|
|
std::ref(*results[t]));
|
|
}
|
|
|
|
for (auto& t : threads) t.join();
|
|
auto end_time = std::chrono::steady_clock::now();
|
|
double elapsed = std::chrono::duration<double>(end_time - start_time).count();
|
|
|
|
// Reduce per-thread results.
|
|
ThreadResult<Scalar> global;
|
|
global.init(opts.hist_width);
|
|
for (int t = 0; t < num_threads; t++) {
|
|
const auto& r = *results[t];
|
|
if (r.max_abs_ulp > global.max_abs_ulp) {
|
|
global.max_abs_ulp = r.max_abs_ulp;
|
|
global.max_ulp_at = r.max_ulp_at;
|
|
global.max_ulp_eigen = r.max_ulp_eigen;
|
|
global.max_ulp_ref = r.max_ulp_ref;
|
|
}
|
|
global.abs_ulp_sum += r.abs_ulp_sum;
|
|
global.count += r.count;
|
|
for (size_t b = 0; b < global.hist.size(); b++) {
|
|
global.hist[b] += r.hist[b];
|
|
}
|
|
}
|
|
|
|
double mean_ulp = global.count > 0 ? global.abs_ulp_sum / global.count : 0.0;
|
|
|
|
// Print results.
|
|
std::printf("Results:\n");
|
|
std::printf(" Values tested: %lu\n", static_cast<unsigned long>(global.count));
|
|
std::printf(" Time: %.2f seconds (%.1f Mvalues/s)\n", elapsed, global.count / elapsed / 1e6);
|
|
if (global.max_abs_ulp == INT64_MAX) {
|
|
std::printf(" Max |ULP error|: inf\n");
|
|
} else {
|
|
std::printf(" Max |ULP error|: %ld\n", static_cast<long>(global.max_abs_ulp));
|
|
}
|
|
std::printf(" at x = %.*g (Eigen=%.*g, ref=%.*g)\n", kDigits, double(global.max_ulp_at), kDigits,
|
|
double(global.max_ulp_eigen), kDigits, double(global.max_ulp_ref));
|
|
std::printf(" Mean |ULP error|: %.4f\n", mean_ulp);
|
|
std::printf("\n");
|
|
|
|
// Print signed error histogram.
|
|
std::printf("Signed ULP error histogram [-%d, +%d]:\n", opts.hist_width, opts.hist_width);
|
|
int nbins = 2 * opts.hist_width + 3;
|
|
for (int b = 0; b < nbins; b++) {
|
|
if (global.hist[b] == 0) continue;
|
|
double pct = 100.0 * global.hist[b] / global.count;
|
|
if (b == 0) {
|
|
std::printf(" <%-4d: %12lu (%7.3f%%)\n", -opts.hist_width, static_cast<unsigned long>(global.hist[b]), pct);
|
|
} else if (b == nbins - 1) {
|
|
std::printf(" >%-4d: %12lu (%7.3f%%)\n", opts.hist_width, static_cast<unsigned long>(global.hist[b]), pct);
|
|
} else {
|
|
int err = b - opts.hist_width - 1;
|
|
std::printf(" %-5d: %12lu (%7.3f%%)\n", err, static_cast<unsigned long>(global.hist[b]), pct);
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
// ============================================================================
|
|
// Command-line parsing
|
|
// ============================================================================
|
|
|
|
static void print_usage() {
|
|
std::printf(
|
|
"Usage: ulp_accuracy [options]\n"
|
|
" --func=NAME Function to test (required unless --list)\n"
|
|
" --lo=VAL Start of range (default: -inf)\n"
|
|
" --hi=VAL End of range (default: +inf)\n"
|
|
" --double Test double precision (default: float)\n"
|
|
" --step=EPS Sampling step: advance by (1+EPS)*nextafter(x)\n"
|
|
" (default: 0 = exhaustive; useful for double, e.g. 1e-6)\n"
|
|
" --threads=N Number of threads (default: all cores)\n"
|
|
" --batch=N Batch size for Eigen eval (default: 4096)\n"
|
|
" --ref=MODE Reference: 'std' (default) or 'mpfr'\n"
|
|
" --hist_width=N Histogram half-width in ULPs (default: 10)\n"
|
|
" --list List available functions\n");
|
|
}
|
|
|
|
int main(int argc, char* argv[]) {
|
|
Options opts;
|
|
opts.num_threads = static_cast<int>(std::thread::hardware_concurrency());
|
|
if (opts.num_threads == 0) opts.num_threads = 4;
|
|
std::string ref_mode;
|
|
|
|
for (int i = 1; i < argc; i++) {
|
|
std::string arg = argv[i];
|
|
if (arg.substr(0, 7) == "--func=") {
|
|
opts.func_name = arg.substr(7);
|
|
} else if (arg.substr(0, 5) == "--lo=") {
|
|
std::string val = arg.substr(5);
|
|
if (val == "inf")
|
|
opts.lo = std::numeric_limits<double>::infinity();
|
|
else if (val == "-inf")
|
|
opts.lo = -std::numeric_limits<double>::infinity();
|
|
else
|
|
opts.lo = std::stod(val);
|
|
} else if (arg.substr(0, 5) == "--hi=") {
|
|
std::string val = arg.substr(5);
|
|
if (val == "inf")
|
|
opts.hi = std::numeric_limits<double>::infinity();
|
|
else if (val == "-inf")
|
|
opts.hi = -std::numeric_limits<double>::infinity();
|
|
else
|
|
opts.hi = std::stod(val);
|
|
} else if (arg.substr(0, 10) == "--threads=") {
|
|
opts.num_threads = std::stoi(arg.substr(10));
|
|
} else if (arg.substr(0, 8) == "--batch=") {
|
|
opts.batch_size = std::stoi(arg.substr(8));
|
|
} else if (arg.substr(0, 6) == "--ref=") {
|
|
ref_mode = arg.substr(6);
|
|
} else if (arg.substr(0, 13) == "--hist_width=") {
|
|
opts.hist_width = std::stoi(arg.substr(13));
|
|
} else if (arg.substr(0, 7) == "--step=") {
|
|
opts.step_eps = std::stod(arg.substr(7));
|
|
} else if (arg == "--double") {
|
|
opts.use_double = true;
|
|
} else if (arg == "--list") {
|
|
opts.list_funcs = true;
|
|
} else if (arg == "--help" || arg == "-h") {
|
|
print_usage();
|
|
return 0;
|
|
} else {
|
|
std::fprintf(stderr, "Unknown option: %s\n", arg.c_str());
|
|
print_usage();
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
// Determine reference mode (default: std).
|
|
if (ref_mode.empty() || ref_mode == "std") {
|
|
opts.use_mpfr = false;
|
|
} else if (ref_mode == "mpfr") {
|
|
#ifdef EIGEN_HAS_MPFR
|
|
opts.use_mpfr = true;
|
|
#else
|
|
std::fprintf(stderr, "Error: MPFR support not compiled in. Use --ref=std or rebuild with MPFR.\n");
|
|
return 1;
|
|
#endif
|
|
} else {
|
|
std::fprintf(stderr, "Error: --ref must be 'std' or 'mpfr'\n");
|
|
return 1;
|
|
}
|
|
|
|
if (!opts.list_funcs && opts.func_name.empty()) {
|
|
std::fprintf(stderr, "Error: --func=NAME is required (use --list to see available functions)\n");
|
|
return 1;
|
|
}
|
|
|
|
if (opts.use_double) {
|
|
return run_test<double>(opts);
|
|
} else {
|
|
return run_test<float>(opts);
|
|
}
|
|
}
|