SecDec/general/src/subexp/symbsub.m [ Mathematica Files ]

[ Top ] [ Mathematica Files ]

NAME

    symbsub.m

USAGE

  is run from subandexpand*l*h*.m

USES

  integrandfunctionlist prepared by formindlist.m

  USED BY 
    
  subandexpand*l*h*.m

PURPOSE

  performs the symbolic subtraction of the integrand to regulate
  singularities in epsilon

INPUTS

  integrandfunctionlist from formindlist.m
  n:number of integration variables 
    
  RESULT
  The variables sizemu,epspower[mu],numcoeff[mu],set[mu] and exponents[mu,i]
  are calculated, corresponding to the subtracted integrand. The integrand is
  treated symbolically. If a variable has the exponent (a[i]+b[i]eps), the b are
  left symbolic, and the a are also left symbolic unless a<=-1. The subtracted integrand
  is represented by the arrays above, and to reconstitute the full (still symbolic) integrand,
  one would do Sum[numcoeff[mu]eps^epspower[mu]Product[z[i]^exponents[mu,i],{i,n}]*
  (settozero[symbolic function,set]),{mu,sizemu}], where set={{z[i1],j1},...{z[ik],jk}},
  and this represents the fact that the symbolic function is to be differentiated j1 times wrt z[i1]
  (j1 can only equal 0 for logarithmic poles, 0 or 1 for linear poles, ...), and then z[i1]->0
  These are then used by formfortran.m to create explict form of the integrand.

SEE ALSO

  subandexpand*l*h*.m, formindlist.m, formfortran.m