Ray-integral factor for the shifted Gaussian: sqrt(2π) · erf(T/√2) − 2·T·exp(−½·T²)
For the unshifted Gaussian this reduces to sqrt(2π) ≈ 2.507. For T=3 the shifted form is ≈ 2.433.
Uses the shared erfRef (A&S 7.1.26, max error 1.5e-7) from _shared/erf.ts — the viewer's single erf source.
erfRef
_shared/erf.ts
Ray-integral factor for the shifted Gaussian: sqrt(2π) · erf(T/√2) − 2·T·exp(−½·T²)
For the unshifted Gaussian this reduces to sqrt(2π) ≈ 2.507. For T=3 the shifted form is ≈ 2.433.
Uses the shared
erfRef(A&S 7.1.26, max error 1.5e-7) from_shared/erf.ts— the viewer's single erf source.