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