Travel time calculation fails in 3-D spherical coordinates

[seishorihori]

Thank you for sharing this Julia code set. It’s very helpful to me.

When I tried to calculate travel time using EikonalSolvers.jl with a 3-D spherical grid, I encountered the following error:

ERROR: LoadError: UndefVarError: `gridspac` not defined
Stacktrace:
  [1] findenclosingbox(grd::Grid3DSphere, xyzsrc::Vector{Float64})
    @ EikonalSolvers ~/.julia/packages/EikonalSolvers/S5c5B/src/EikSolv/eikmainfwd.jl:1140
  [2] createfinegrid(grd::Grid3DSphere, xyzsrc::Vector{Float64}, vel::Array{Float64, 3}, grdrefpars::GridRefinementPars)
    @ EikonalSolvers ~/.julia/packages/EikonalSolvers/S5c5B/src/EikSolv/eikmainfwd.jl:976
  [3] runrefinementaroundsrc!(fmmvars::EikonalSolvers.FMMVars3D, vel::Array{Float64, 3}, xyzsrc::Vector{Float64}, grd::Grid3DSphere, adjvars::Nothing, extrapars::ExtraParams)
    @ EikonalSolvers ~/.julia/packages/EikonalSolvers/S5c5B/src/EikSolv/eikmainfwd.jl:350
  [4] ttFMM_hiord!(fmmvars::EikonalSolvers.FMMVars3D, vel::Array{Float64, 3}, src::Vector{Float64}, grd::Grid3DSphere, adjvars::Nothing, extrapars::ExtraParams)
    @ EikonalSolvers ~/.julia/packages/EikonalSolvers/S5c5B/src/EikSolv/eikmainfwd.jl:290
  [5] ttFMM_hiord!
    @ ~/.julia/packages/EikonalSolvers/S5c5B/src/EikSolv/eikmainfwd.jl:224 [inlined]
  [6] ttforwsomesrc(vel::Array{Float64, 3}, coordsrc::Matrix{Float64}, coordrec::Vector{Matrix{Float64}}, grd::Grid3DSphere, extrapars::ExtraParams; returntt::Bool)
    @ EikonalSolvers ~/.julia/packages/EikonalSolvers/S5c5B/src/EikSolv/eikmainfwd.jl:180
  [7] ttforwsomesrc
    @ ~/.julia/packages/EikonalSolvers/S5c5B/src/EikSolv/eikmainfwd.jl:152 [inlined]
  [8] eiktraveltime(vel::Array{Float64, 3}, grd::Grid3DSphere, coordsrc::Matrix{Float64}, coordrec::Vector{Matrix{Float64}}; returntt::Bool, extraparams::Nothing)
    @ EikonalSolvers ~/.julia/packages/EikonalSolvers/S5c5B/src/EikSolv/eikmainfwd.jl:129
  [9] eiktraveltime
    @ ~/.julia/packages/EikonalSolvers/S5c5B/src/EikSolv/eikmainfwd.jl:33 [inlined]
 [10] main()
~/EikonalSolvers/3Dspherical_toy.jl:72
 [11] top-level scope
    @ ~/EikonalSolvers/3Dspherical_toy.jl:83

At line 1140, the code is
xyzres[d],remainder[d] = divrem(xyzsrc[d]-xyzinit[d],gridspac[d])
Here "gridspac" is required.

From what I understand, "gridspac" is defined inside an if-block on lines 1122–1131 of eikmainfwd.jl.
However, this if-block does not handle the case where typeof(grd)==Grid3DSphere
I believe that this is a cause of the error.

I'm using EikonalSolvers.jl v0.15.3 and Julia 1.10.10 on macOS 15.7.3.
Thank you in advance.