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SetCollierLinkOptions

SetCollierLinkOptions[namevalue]
resets the value of the global CollierLink option with the specified name.

Details and OptionsDetails and Options

  • Options set with SetCollierLinkOptions influence the numerical evaluation of PVA, PVB, PVC, PVD, PVX as well as of CollierCompiledFunction objects.
  • The following options are available:
  • optiondefaultCOLLIER library callNotes
    "MaxDenominators"6n/amaximum number of denominator factors for which Passarino-Veltman functions can be numerically evaluated; locked at 6
    "MaxRank"6Init_cllhighest rank for which Passarino-Veltman functions can be numerically evaluated
    "Mode"1SetMode_cllbranch of COLLIER library to use for numerical evaluation. 1=COLI, 2=DD, 3=both branches
    "InvEpsUV"0.0SetDeltaUV_cllnumerical value of ultraviolet poles
    "MuUV"1.0SetMuUV2_cllvalue of 't Hooft mass parameter in logarithms associated with ultraviolet divergences.
    "InvEpsIR"{0.0,0.0}SetDeltaIR_cllnumerical values of infrared {, } poles
    "MuIR"1.0SetMuIR2_cllvalue of 't Hooft mass parameter in logarithms associated with infrared divergences.
    "SmallMasses"{}Setminf2_cllnumerical values of masses to be treated as regulators for infrared divergent Passarino-Veltman functions.
    "ReqAcc"1.0*^-8SetReqAcc_clltarget precision aimed at in the calculation of Passarino-Veltman functions.
    "RitMax"14SetRitmax_cllmaximal rank up to which Passarino-Veltman functions are calculated in iterative methods
  • Modifying "MaxRank" resets all other options to their default values.
  • "MuUV", "MuIR", and "SmallMasses" should be set to values of masses, and not their squares. The square is automatically calculated when the respective COLLIER library subroutine is called.
  • "InvEpsIR" should be set to values of {, } in the convention of Package-X. A constant shift of is automatically added to when SetDeltaIR_cll is called.
  • CollierLinkOptions[] gives the current settings.

ExamplesExamplesopen allclose all

Basic Examples  (4)Basic Examples  (4)

By default, Passarino-Veltman functions are evaluated using the COLI branch:

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Evaluate using the DD branch:

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Use a different value for the UV pole and accompanying 't Hooft mass parameter :

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Compare with the analytic result of LoopRefine:

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Use a small mass to regulate an IR divergent integral:

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Lowering the required accuracy may introduce numerical noise close to the region of vanishing Gram determinant:

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