TemporalHazard 1.2.15

Bug fixes

• A multiphase fit no longer selects a start that ran away to an
  underflow (#600). For an early phase with m = 0 and nu < 0,
  hzr_decompos() computed the CDF as 1 - exp(-x), which rounds to
  exactly 0 once x is below about 1e-16, while the density, formed
  directly, stayed positive. Where that happened the cumulative hazard
  vanished and the hazard did not, so the likelihood had a false peak that
  rose without bound in mu. On the avc data, the m-fixed model started
  from t_half = 0.5, nu = 1, mu = 1 with the default five starts
  climbed it to log(mu) 130 and a log-likelihood of +6380.86, and returned
  that start as the fit with converged = TRUE; three of the other four
  reach -214.875. The CDF is now -expm1(-x), as the m > 0, nu < 0
  branch already had it, and the same call returns -214.875. The two forms
  round differently everywhere, not only near 0, so other fits with an
  m = 0, nu < 0 phase can change in their last digits (by about 1e-15
  relative); fits without one are unchanged.

Tests

• Two tests now pin the speed-up from 1.2.14's CoE gradient cache (#631).
  One counts the per-phase work and checks that a call matching the cache
  key does none, and that changing any one of theta, the times or the
  entry times alone forces it. The other runs a real CoE fit and checks that
  the second gradient evaluation at each point reuses the first's cache and
  does no work. The existing test compared gradients, which a recomputed
  value matches too, so it passed with caching switched off, with theta,
  the times or the entry times dropped from the key, and with the CoE
  wrapper handing its second evaluation a fresh cache. The new tests fail on
  each of those.