fix epsilon for Float16 #190
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mcabbott
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Nov 6, 2024
src/rules.jl
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| η, ρ, ϵ = T(o.eta), T(o.rho), T(o.epsilon) | ||
| ϵ = max(ϵ, eps(T(0))) |
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I don't think this does the right thing:
julia> eps(Float32) # roughly what we hard-code now
1.1920929f-7
julia> eps(0f0) # what this PR uses
1.0f-45
I think a better pattern is this:
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| η, ρ, ϵ = T(o.eta), T(o.rho), T(o.epsilon) | |
| ϵ = max(ϵ, eps(T(0))) | |
| η, ρ, ϵ = T(o.eta), T(o.rho), max(T(o.epsilon), eps(T)) |
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I chose eps(T(0)) because i didn't want to change the current behavior eps=1f-8 for Float32 but do the minimal change needed for Float16
julia> eps(Float16)
Float16(0.000977)
julia> eps(Float16(0))
Float16(6.0e-8)There was a problem hiding this comment.
Ok. How broadly is 6e-8 big enough for this purpose? It seems a little random... maybe I'd be happier to hard-code an obviously chosen number, which is what 1e-8 is... like _eps(::Type{Float16}, e) = max(1e-7, e)?
ToucheSir
reviewed
Nov 6, 2024
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Fix #167 adding
ϵ = max(ϵ, eps(T(0))).Also fix #189