VVIObjF Class Reference

#include <VVIObjF.h>

Public Member Functions
float	fcn (float x) const
void	limits (float &xl, float &xu) const
	density (mode=0) or distribution (mode=1) function More...
	VVIObjF (float kappa=0.01, float beta2=1., int mode=0)
	Constructor. More...

Private Attributes
float	a_ [155]
float	b_ [155]
const int	mode_
	returns the limits on the non-zero (mode=0) or normalized region (mode=1) More...
float	omega_
float	t0_
float	t1_
float	t_
float	x0_

Detailed Description

Port of CERNLIB routines vvidis/vviden (G116) to calculate higher quality Vavilov density and distribution functions

Definition at line 24 of file VVIObjF.h.

Constructor & Destructor Documentation

VVIObjF::VVIObjF	(	float	kappa = 0.01,
		float	beta2 = 1.,
		int	mode = 0
	)

Constructor.

Constructor Set Vavilov parameters kappa and beta2 and define whether to calculate density fcn or distribution fcn

Parameters

kappa	- (input) Vavilov kappa parameter [0.01 (Landau-like) < kappa < 10. (Gaussian-like)]
beta2	- (input) Vavilov beta2 parameter (square of particle speed in v/c units)
mode	- (input) set to 0 to calculate the density function and to 1 to calculate the distribution function

Definition at line 41 of file VVIObjF.cc.

References a_, funct::abs(), b_, c, alignmentValidation::c1, ztail::d, d1, VVIObjFDetails::dzero(), alignCSCRings::e, VVIObjFDetails::expint(), validate-o2o-wbm::f, validate-o2o-wbm::f1, validate-o2o-wbm::f2, myMath::fast_expf(), myMath::fast_logf(), isotrackApplyRegressor::k, cmsLHEtoEOSManager::l, mode_, dqmiodumpmetadata::n, omega_, submitPVResolutionJobs::q, alignCSCRings::s, VVIObjFDetails::sincosint(), t0_, t1_, t_, x, and x0_.

                                                   : mode_(mode) {
  const float xp[9] = {9.29, 2.47, .89, .36, .15, .07, .03, .02, 0.0};
  const float xq[7] = {.012, .03, .08, .26, .87, 3.83, 11.0};
  float h_[7];
  float q, u, x, c1, c2, c3, c4, d1, h4, h5, h6, q2, x1, d, ll, ul, xf1, xf2, rv;
  int lp, lq, k, l, n;

  // Make sure that the inputs are reasonable

  if (kappa < 0.01f)
    kappa = 0.01f;
  if (kappa > 10.f)
    kappa = 10.f;
  if (beta2 < 0.f)
    beta2 = 0.f;
  if (beta2 > 1.f)
    beta2 = 1.f;

  float invKappa = 1.f / kappa;
  h_[4] = 1.f - beta2 * 0.42278433999999998f + (7.6f * invKappa);
  h_[5] = beta2;
  h_[6] = 1.f - beta2;
  h4 = -(7.6f * invKappa) - (beta2 * .57721566f + 1.f);
  h5 = vdt::fast_logf(kappa);
  h6 = invKappa;
  t0_ = (h4 - h_[4] * h5 - (h_[4] + beta2) * (vdt::fast_logf(h_[4]) + VVIObjFDetails::expint(h_[4])) +
         vdt::fast_expf(-h_[4])) /
        h_[4];

  // Set up limits for the root search

  for (lp = 0; lp < 9; ++lp) {
    if (kappa >= xp[lp])
      break;
  }
  ll = -float(lp) - 1.5f;
  for (lq = 0; lq < 7; ++lq) {
    if (kappa <= xq[lq])
      break;
  }
  ul = lq - 6.5f;
  auto f2 = [h_](float x) {
    return h_[4] - x + h_[5] * (vdt::fast_logf(std::abs(x)) + VVIObjFDetails::expint(x)) - h_[6] * vdt::fast_expf(-x);
  };
  VVIObjFDetails::dzero(ll, ul, u, rv, 1.e-3f, 100, f2);
  q = 1. / u;
  t1_ = h4 * q - h5 - (beta2 * q + 1.f) * (vdt::fast_logf((fabs(u))) + VVIObjFDetails::expint(u)) +
        vdt::fast_expf(-u) * q;
  t_ = t1_ - t0_;
  omega_ = 6.2831853000000004f / t_;
  h_[0] = kappa * (beta2 * .57721566f + 2.f) + 9.9166128600000008f;
  if (kappa >= .07) {
    h_[0] += 6.90775527f;
  }
  h_[1] = beta2 * kappa;
  h_[2] = h6 * omega_;
  h_[3] = omega_ * 1.5707963250000001f;
  auto f1 = [h_](float x) { return h_[0] + h_[1] * vdt::fast_logf(h_[2] * x) - h_[3] * x; };
  VVIObjFDetails::dzero(5.f, 155.f, x0_, rv, 1.e-3f, 100, f1);
  n = x0_ + 1.;
  d = vdt::fast_expf(kappa * (beta2 * (.57721566f - h5) + 1.f)) * .31830988654751274f;
  a_[n - 1] = 0.f;
  if (mode_ == 0) {
    a_[n - 1] = omega_ * .31830988654751274f;
  }
  q = -1.;
  q2 = 2.;
  for (k = 1; k < n; ++k) {
    l = n - k;
    x = omega_ * k;
    x1 = h6 * x;
    VVIObjFDetails::sincosint(x1, c2, c1);
    c1 = vdt::fast_logf(x) - c1;
    vdt::fast_sincosf(x1, c3, c4);
    xf1 = kappa * (beta2 * c1 - c4) - x * c2;
    xf2 = x * c1 + kappa * (c3 + beta2 * c2) + t0_ * x;
    float s, c;
    vdt::fast_sincosf(xf2, s, c);
    if (mode_ == 0) {
      d1 = q * d * omega_ * vdt::fast_expf(xf1);
      a_[l - 1] = d1 * c;
      b_[l - 1] = -d1 * s;
    } else {
      d1 = q * d * vdt::fast_expf(xf1) / k;
      a_[l - 1] = d1 * s;
      b_[l - 1] = d1 * c;
      a_[n - 1] += q2 * a_[l - 1];
    }
    q = -q;
    q2 = -q2;
  }

}  // VVIObjF

Member Function Documentation

float VVIObjF::fcn

(

float

x

)

const

Vavilov function method Returns density fcn (mode=0) or distribution fcn (mode=1)

Parameters

x	- (input) Argument of function [typically defined as (Q-mpv)/sigma]

Definition at line 141 of file VVIObjF.cc.

References a0, isotrackTrainRegressor::a1, isotrackTrainRegressor::a2, a_, b0, b1, b2, b_, validate-o2o-wbm::f, isotrackApplyRegressor::k, mode_, dqmiodumpmetadata::n, omega_, t0_, t1_, t_, x0_, and y.

Referenced by SiPixelTemplateReco::PixelTempReco1D(), and SiPixelTemplateReco2D::PixelTempReco2D().

                                {
  // Local variables

  float f, u, y, a0, a1;
  float a2 = 0.;
  float b1, b0, b2, cof;
  int k, n, n1;

  n = x0_;
  if (x < t0_) {
    f = 0.f;
  } else if (x <= t1_) {
    y = x - t0_;
    u = omega_ * y - 3.141592653589793f;
    float su, cu;
    vdt::fast_sincosf(u, su, cu);
    cof = cu * 2.f;
    a1 = 0.;
    a0 = a_[0];
    n1 = n + 1;
    for (k = 2; k <= n1; ++k) {
      a2 = a1;
      a1 = a0;
      a0 = a_[k - 1] + cof * a1 - a2;
    }
    b1 = 0.;
    b0 = b_[0];
    for (k = 2; k <= n; ++k) {
      b2 = b1;
      b1 = b0;
      b0 = b_[k - 1] + cof * b1 - b2;
    }
    f = (a0 - a2) * .5f + b0 * su;
    if (mode_ != 0) {
      f += y / t_;
    }
  } else {
    f = 0.f;
    if (mode_ != 0) {
      f = 1.f;
    }
  }
  return f;
}  // fcn

void VVIObjF::limits	(	float &	xl,
		float &	xu
	)		const

density (mode=0) or distribution (mode=1) function

Vavilov limits method

Parameters

xl	- (output) Smallest value of the argument for the density and the beginning of the normalized region for the distribution
xu	- (output) Largest value of the argument for the density and the end of the normalized region for the distribution

Definition at line 192 of file VVIObjF.cc.

References t0_, and t1_.

                                               {
  xl = t0_;
  xu = t1_;
  return;
}  // limits

Member Data Documentation

float VVIObjF::a_[155]

private

Definition at line 41 of file VVIObjF.h.

Referenced by fcn(), and VVIObjF().

float VVIObjF::b_[155]

private

Definition at line 42 of file VVIObjF.h.

Referenced by fcn(), and VVIObjF().

const int VVIObjF::mode_

private

returns the limits on the non-zero (mode=0) or normalized region (mode=1)

set to 0 to calculate the density function and to 1 to calculate the distribution function

Definition at line 35 of file VVIObjF.h.

Referenced by fcn(), and VVIObjF().

float VVIObjF::omega_

private

Definition at line 39 of file VVIObjF.h.

Referenced by fcn(), and VVIObjF().

float VVIObjF::t0_

private

Definition at line 36 of file VVIObjF.h.

Referenced by fcn(), limits(), and VVIObjF().

float VVIObjF::t1_

private

Definition at line 37 of file VVIObjF.h.

Referenced by fcn(), limits(), and VVIObjF().

float VVIObjF::t_

private

Definition at line 38 of file VVIObjF.h.

Referenced by fcn(), and VVIObjF().

float VVIObjF::x0_

private

Definition at line 40 of file VVIObjF.h.

Referenced by fcn(), and VVIObjF().