def accbuilder(time, knots, coeffs):
# build acceptance function
from copy import deepcopy
myknots = deepcopy(knots)
mycoeffs = deepcopy(coeffs)
from ROOT import (RooBinning, RooArgList, RooPolyVar,
RooCubicSplineFun)
if (len(myknots) != len(mycoeffs) or 0 >= min(len(myknots), len(mycoeffs))):
raise ValueError('ERROR: Spline knot position list and/or coefficient'
'list mismatch')
# create the knot binning
knotbinning = WS(ws, RooBinning(time.getMin(), time.getMax(), 'knotbinning'))
for v in myknots:
knotbinning.addBoundary(v)
knotbinning.removeBoundary(time.getMin())
knotbinning.removeBoundary(time.getMax())
knotbinning.removeBoundary(time.getMin())
knotbinning.removeBoundary(time.getMax())
oldbinning, lo, hi = time.getBinning(), time.getMin(), time.getMax()
time.setBinning(knotbinning, 'knotbinning')
time.setBinning(oldbinning)
time.setRange(lo, hi)
del knotbinning
del oldbinning
del lo
del hi
# create the knot coefficients
coefflist = RooArgList()
i = 0
for v in mycoeffs:
coefflist.add(WS(ws, RooRealVar('SplineAccCoeff%u' % i,
'SplineAccCoeff%u' % i, v)))
i = i + 1
del mycoeffs
coefflist.add(one)
i = i + 1
myknots.append(time.getMax())
myknots.reverse()
fudge = (myknots[0] - myknots[1]) / (myknots[2] - myknots[1])
lastmycoeffs = RooArgList(
WS(ws, RooConstVar('SplineAccCoeff%u_coeff0' % i,
'SplineAccCoeff%u_coeff0' % i, 1. - fudge)),
WS(ws, RooConstVar('SplineAccCoeff%u_coeff1' % i,
'SplineAccCoeff%u_coeff1' % i, fudge)))
del myknots
coefflist.add(WS(ws, RooPolyVar(
'SplineAccCoeff%u' % i, 'SplineAccCoeff%u' % i,
coefflist.at(coefflist.getSize() - 2), lastmycoeffs)))
del i
# create the spline itself
tacc = WS(ws, RooCubicSplineFun('SplineAcceptance', 'SplineAcceptance', time,
'knotbinning', coefflist))
del lastmycoeffs
# make sure the acceptance is <= 1 for generation
m = max([coefflist.at(j).getVal() for j in
xrange(0, coefflist.getSize())])
from ROOT import RooProduct
c = WS(ws, RooConstVar('SplineAccNormCoeff', 'SplineAccNormCoeff', 0.99 / m))
tacc_norm = WS(ws, RooProduct('SplineAcceptanceNormalised',
'SplineAcceptanceNormalised', RooArgList(tacc, c)))
del c
del m
del coefflist
return tacc, tacc_norm
def buildSplineAcceptance(
ws, # workspace into which to import
time, # time variable
pfx, # prefix to be used in names
knots, # knots
coeffs, # acceptance coefficients
floatParams = False, # float acceptance parameters
debug = False # debug printout
):
"""
build a spline acceptance function
ws -- workspace into which to import acceptance functions
time -- time observable
pfx -- prefix (mode name) from which to build object names
knots -- list of knot positions
coeffs -- spline coefficients
floatParams -- if True, spline acceptance parameters will be floated
debug -- if True, print some debugging output
returns a pair of acceptance functions, first the unnormalised one for
fitting, then the normalised one for generation
The minimum and maximum of the range of the time variable implicitly
defines the position of the first and last knot. The other knot positions
are passed in knots. Conversely, the coeffs parameter records the height
of the sline at all but the last two knot positions. The next to last knot
coefficient is fixed to 1.0, thus fixing the overall scale of the
acceptance function. The spline coefficient for the last knot is fixed by
extrapolating linearly from the two knots before; this prevents
statistical fluctuations at the low stats high lifetime end of the
spectrum to curve the spline.
"""
# build acceptance function
from copy import deepcopy
myknots = deepcopy(knots)
mycoeffs = deepcopy(coeffs)
from ROOT import (RooBinning, RooArgList, RooPolyVar, RooCubicSplineFun,
RooConstVar, RooProduct, RooRealVar)
if (len(myknots) != len(mycoeffs) or 0 >= min(len(myknots), len(mycoeffs))):
raise ValueError('ERROR: Spline knot position list and/or coefficient'
'list mismatch')
one = WS(ws, RooConstVar('one', '1', 1.0))
# create the knot binning
knotbinning = WS(ws, RooBinning(time.getMin(), time.getMax(),
'%s_knotbinning' % pfx))
for v in myknots:
knotbinning.addBoundary(v)
knotbinning.removeBoundary(time.getMin())
knotbinning.removeBoundary(time.getMax())
knotbinning.removeBoundary(time.getMin())
knotbinning.removeBoundary(time.getMax())
oldbinning, lo, hi = time.getBinning(), time.getMin(), time.getMax()
time.setBinning(knotbinning, '%s_knotbinning' % pfx)
time.setBinning(oldbinning)
time.setRange(lo, hi)
del knotbinning
del oldbinning
del lo
del hi
# create the knot coefficients
coefflist = RooArgList()
i = 0
for v in mycoeffs:
if floatParams:
coefflist.add(WS(ws, RooRealVar('%s_SplineAccCoeff%u' % (pfx, i),
'v_{%u}' % (i+1), v, 0., 3.)))
else:
coefflist.add(WS(ws, RooConstVar('%s_SplineAccCoeff%u' % (pfx, i),
'v_{%u}' % (i+1), v)))
i = i + 1
del mycoeffs
coefflist.add(one)
i = i + 1
myknots.append(time.getMax())
myknots.reverse()
fudge = (myknots[0] - myknots[1]) / (myknots[2] - myknots[1])
lastmycoeffs = RooArgList(
WS(ws, RooConstVar('%s_SplineAccCoeff%u_coeff0' % (pfx, i),
'%s_SplineAccCoeff%u_coeff0' % (pfx, i), 1. - fudge)),
WS(ws, RooConstVar('%s_SplineAccCoeff%u_coeff1' % (pfx, i),
'%s_SplineAccCoeff%u_coeff1' % (pfx, i), fudge)))
del myknots
coefflist.add(WS(ws, RooPolyVar(
'%s_SplineAccCoeff%u' % (pfx, i), 'v_{%u}' % (i+1),
coefflist.at(coefflist.getSize() - 2), lastmycoeffs)))
del i
if debug:
print 'DEBUG: Spline Coeffs: %s' % str([
coefflist.at(i).getVal() for i in xrange(0, coefflist.getSize())
])
# create the spline itself
tacc = WS(ws, RooCubicSplineFun('%s_SplineAcceptance' % pfx,
'%s_SplineAcceptance' % pfx, time, '%s_knotbinning' % pfx,
coefflist))
del lastmycoeffs
if not floatParams:
# make sure the acceptance is <= 1 for generation
m = max([coefflist.at(j).getVal() for j in
xrange(0, coefflist.getSize())])
c = WS(ws, RooConstVar('%s_SplineAccNormCoeff' % pfx,
'%s_SplineAccNormCoeff' % pfx, 0.99 / m))
tacc_norm = WS(ws, RooProduct('%s_SplineAcceptanceNormalised' % pfx,
'%s_SplineAcceptanceNormalised' % pfx, RooArgList(tacc, c)))
del c
del m
else:
tacc_norm = None # not supported when floating
del coefflist
return tacc, tacc_norm