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79 lines
2.5 KiB
C++
79 lines
2.5 KiB
C++
// MPFR high-precision reference implementations for ULP accuracy testing.
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//
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// This header provides MPFR-based reference functions for all math operations
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// tested by the ulp_accuracy tool. It also includes scalar conversion helpers
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// between float/double and mpfr_t.
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//
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// Only compiled when EIGEN_HAS_MPFR is defined (i.e., MPFR and GMP are found).
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#ifndef EIGEN_ULP_ACCURACY_MPFR_REFERENCE_H
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#define EIGEN_ULP_ACCURACY_MPFR_REFERENCE_H
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#ifdef EIGEN_HAS_MPFR
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#include <mpfr.h>
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// ---------------------------------------------------------------------------
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// Scalar <-> mpfr_t conversion
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// ---------------------------------------------------------------------------
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template <typename Scalar>
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static void mpfr_set_scalar(mpfr_t rop, Scalar x, mpfr_rnd_t rnd);
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template <>
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void mpfr_set_scalar<float>(mpfr_t rop, float x, mpfr_rnd_t rnd) {
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mpfr_set_flt(rop, x, rnd);
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}
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template <>
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void mpfr_set_scalar<double>(mpfr_t rop, double x, mpfr_rnd_t rnd) {
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mpfr_set_d(rop, x, rnd);
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}
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template <typename Scalar>
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static Scalar mpfr_get_scalar(mpfr_t op, mpfr_rnd_t rnd);
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template <>
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float mpfr_get_scalar<float>(mpfr_t op, mpfr_rnd_t rnd) {
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return mpfr_get_flt(op, rnd);
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}
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template <>
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double mpfr_get_scalar<double>(mpfr_t op, mpfr_rnd_t rnd) {
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return mpfr_get_d(op, rnd);
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}
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// ---------------------------------------------------------------------------
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// MPFR wrappers for functions not directly provided by libmpfr
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// ---------------------------------------------------------------------------
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// logistic(x) = 1 / (1 + exp(-x))
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static int mpfr_logistic(mpfr_t rop, const mpfr_t op, mpfr_rnd_t rnd) {
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mpfr_t tmp, one;
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mpfr_init2(tmp, mpfr_get_prec(rop));
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mpfr_init2(one, mpfr_get_prec(rop));
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mpfr_set_ui(one, 1, rnd);
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mpfr_neg(tmp, op, rnd);
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mpfr_exp(tmp, tmp, rnd);
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mpfr_add(tmp, tmp, one, rnd);
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int ret = mpfr_div(rop, one, tmp, rnd);
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mpfr_clear(tmp);
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mpfr_clear(one);
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return ret;
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}
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// rsqrt(x) = 1 / sqrt(x)
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static int mpfr_rsqrt(mpfr_t rop, const mpfr_t op, mpfr_rnd_t rnd) { return mpfr_rec_sqrt(rop, op, rnd); }
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// exp2(x) = 2^x
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static int mpfr_exp2_wrap(mpfr_t rop, const mpfr_t op, mpfr_rnd_t rnd) {
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mpfr_t two;
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mpfr_init2(two, mpfr_get_prec(rop));
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mpfr_set_ui(two, 2, rnd);
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int ret = mpfr_pow(rop, two, op, rnd);
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mpfr_clear(two);
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return ret;
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}
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// log2(x) — thin wrapper to match the function signature convention.
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static int mpfr_log2_wrap(mpfr_t rop, const mpfr_t op, mpfr_rnd_t rnd) { return mpfr_log2(rop, op, rnd); }
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#endif // EIGEN_HAS_MPFR
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#endif // EIGEN_ULP_ACCURACY_MPFR_REFERENCE_H
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