[BUG] can't plot with default colour scale with high precision floats

[dahtah]

There's an issue with the limits of the default colour scale when plotting with high precision floats (e.g. BigFloats).

Details

When plotting data that isn't Float64s but higher precision floats (like BigFloats, or ArbFloats from the ArbNumerics package), the following issue sometimes appears:

a=-exp(-BigFloat(8))
b=BigFloat(1)
heatmap([a b; b a]) 
#fails with
#ERROR: BoundsError: attempt to access 256-element Vector{Float64} at index [257]

Backends

Presumably all backends, this bug originates in colorschemes.jl

Versions

Plots.jl version: 1.31.1 Backend version (]st -m <backend(s)>): irrelevant Output of versioninfo(): Julia Version 1.7.3 Commit 742b9abb4d (2022-05-06 12:58 UTC) Platform Info: OS: Linux (x86_64-pc-linux-gnu) CPU: Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz WORD_SIZE: 64 LIBM: libopenlibm LLVM: libLLVM-12.0.1 (ORCJIT, skylake) Environment: JULIA_ERROR_COLOR = magenta JULIA_EDITOR = emacsclient

[t-bltg]

this bug originates in colorschemes.jl

If that is the case (it would be better to provide the full stacktrace), the bug should be reported to ColorSchemes.jl.

[nilshg]

I think OP meant the files colorschemes.jl in PlotUtils - just had a user on Discourse run into this, here's the stacktrace:

julia> heatmap(rand(BigFloat, 200, 200))
Error showing value of type Plots.Plot{Plots.GRBackend}:
ERROR: BoundsError: attempt to access 256-element Vector{Float64} at index [257]
Stacktrace:
  [1] getindex
    @ .\essentials.jl:13 [inlined]
  [2] get(cg::PlotUtils.ContinuousColorGradient, x::BigFloat, rangescale::Tuple{Float64, Float64})
    @ PlotUtils C:\Users\ngudat\.julia\packages\PlotUtils\M092a\src\colorschemes.jl:68
  [3] (::PlotUtils.var"#6#7"{PlotUtils.ContinuousColorGradient})(x::BigFloat)
    @ PlotUtils C:\Users\ngudat\.julia\packages\PlotUtils\M092a\src\colorschemes.jl:29
  [4] iterate
    @ .\generator.jl:47 [inlined]
  [5] collect_to!(dest::Matrix{RGBA{BigFloat}}, itr::Base.Generator{Matrix{BigFloat}, PlotUtils.var"#6#7"{PlotUtils.ContinuousColorGradient}}, offs::Int64, st::Int64)
    @ Base .\array.jl:840
  [6] collect_to_with_first!(dest::Matrix{RGBA{BigFloat}}, v1::RGBA{BigFloat}, itr::Base.Generator{Matrix{BigFloat}, PlotUtils.var"#6#7"{PlotUtils.ContinuousColorGradient}}, st::Int64)
    @ Base .\array.jl:818
  [7] _collect(c::Matrix{BigFloat}, itr::Base.Generator{Matrix{BigFloat}, PlotUtils.var"#6#7"{PlotUtils.ContinuousColorGradient}}, #unused#::Base.EltypeUnknown, isz::Base.HasShape{2})
    @ Base .\array.jl:812
  [8] collect_similar
    @ .\array.jl:711 [inlined]
  [9] map
    @ .\abstractarray.jl:3255 [inlined]
 [10] get(cg::PlotUtils.ContinuousColorGradient, v::Matrix{BigFloat}, rangescale::Tuple{Float64, Float64})
    @ PlotUtils C:\Users\ngudat\.julia\packages\PlotUtils\M092a\src\colorschemes.jl:29
 [11] gr_draw_heatmap(series::Plots.Series, x::Vector{Float64}, y::Vector{Float64}, z::Matrix{BigFloat}, clims::Tuple{Float64, Float64})
    @ Plots C:\Users\ngudat\.julia\packages\Plots\nuwp4\src\backends\gr.jl:1954
 [12] gr_add_series(sp::Plots.Subplot{Plots.GRBackend}, series::Plots.Series)
    @ Plots C:\Users\ngudat\.julia\packages\Plots\nuwp4\src\backends\gr.jl:1728
 [13] gr_display(sp::Plots.Subplot{Plots.GRBackend}, w::Measures.AbsoluteLength, h::Measures.AbsoluteLength, vp_canvas::Plots.GRViewport{Float64})
    @ Plots C:\Users\ngudat\.julia\packages\Plots\nuwp4\src\backends\gr.jl:956
 [14] (::Plots.var"#528#529"{Int64, Int64, Plots.GRViewport{Float64}})(sp::Plots.Subplot{Plots.GRBackend})
    @ Plots C:\Users\ngudat\.julia\packages\Plots\nuwp4\src\backends\gr.jl:680
 [15] foreach(f::Plots.var"#528#529"{Int64, Int64, Plots.GRViewport{Float64}}, itr::Vector{Plots.Subplot})
    @ Base .\abstractarray.jl:3067
 [16] gr_display(plt::Plots.Plot{Plots.GRBackend}, dpi_factor::Int64)
    @ Plots C:\Users\ngudat\.julia\packages\Plots\nuwp4\src\backends\gr.jl:680
 [17] gr_display
    @ C:\Users\ngudat\.julia\packages\Plots\nuwp4\src\backends\gr.jl:650 [inlined]
 [18] #574
    @ C:\Users\ngudat\.julia\packages\Plots\nuwp4\src\backends\gr.jl:2044 [inlined]
 [19] withenv(::Plots.var"#574#576"{Plots.Plot{Plots.GRBackend}}, ::Pair{String, String}, ::Vararg{Pair{String}})
    @ Base .\env.jl:197
 [20] _display(plt::Plots.Plot{Plots.GRBackend})
    @ Plots C:\Users\ngudat\.julia\packages\Plots\nuwp4\src\backends\gr.jl:2043
 [21] display(#unused#::Plots.PlotsDisplay, plt::Plots.Plot{Plots.GRBackend})
    @ Plots C:\Users\ngudat\.julia\packages\Plots\nuwp4\src\output.jl:174
 [22] display(x::Any)
    @ Base.Multimedia .\multimedia.jl:340
 [23] #invokelatest#2
    @ .\essentials.jl:816 [inlined]
 [24] invokelatest
    @ .\essentials.jl:813 [inlined]
 [25] print_response(errio::IO, response::Any, show_value::Bool, have_color::Bool, specialdisplay::Union{Nothing, AbstractDisplay})
    @ REPL C:\Users\ngudat\AppData\Local\Programs\Julia-1.9.0-beta3\share\julia\stdlib\v1.9\REPL\src\REPL.jl:302
 [26] (::REPL.var"#57#58"{REPL.LineEditREPL, Pair{Any, Bool}, Bool, Bool})(io::Any)
    @ REPL C:\Users\ngudat\AppData\Local\Programs\Julia-1.9.0-beta3\share\julia\stdlib\v1.9\REPL\src\REPL.jl:284
 [27] with_repl_linfo(f::Any, repl::REPL.LineEditREPL)
    @ REPL C:\Users\ngudat\AppData\Local\Programs\Julia-1.9.0-beta3\share\julia\stdlib\v1.9\REPL\src\REPL.jl:551
 [28] print_response(repl::REPL.AbstractREPL, response::Any, show_value::Bool, have_color::Bool)
    @ REPL C:\Users\ngudat\AppData\Local\Programs\Julia-1.9.0-beta3\share\julia\stdlib\v1.9\REPL\src\REPL.jl:282
 [29] (::REPL.var"#do_respond#80"{Bool, Bool, REPL.var"#93#103"{REPL.LineEditREPL, REPL.REPLHistoryProvider}, REPL.LineEditREPL, REPL.LineEdit.Prompt})(s::REPL.LineEdit.MIState, buf::Any, ok::Bool)
    @ REPL C:\Users\ngudat\AppData\Local\Programs\Julia-1.9.0-beta3\share\julia\stdlib\v1.9\REPL\src\REPL.jl:893
 [30] #invokelatest#2
    @ .\essentials.jl:816 [inlined]
 [31] invokelatest
    @ .\essentials.jl:813 [inlined]
 [32] run_interface(terminal::REPL.Terminals.TextTerminal, m::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
    @ REPL.LineEdit C:\Users\ngudat\AppData\Local\Programs\Julia-1.9.0-beta3\share\julia\stdlib\v1.9\REPL\src\LineEdit.jl:2644
 [33] run_frontend(repl::REPL.LineEditREPL, backend::REPL.REPLBackendRef)
    @ REPL C:\Users\ngudat\AppData\Local\Programs\Julia-1.9.0-beta3\share\julia\stdlib\v1.9\REPL\src\REPL.jl:1293
 [34] (::REPL.var"#62#68"{REPL.LineEditREPL, REPL.REPLBackendRef})()
    @ REPL .\task.jl:514

[t-bltg]

@nilshg, your example doesn't error ?

Xref https://discourse.julialang.org/t/display-function-returning-boundserror/93548

[nilshg]

Hm, you're right - it only errors when one adds AssociatedLegendrePolynomials and SpecialFunctions to the environment - maybe that restricts some transitive dependency to an older version? Plots is at 1.38.2 in both cases.

[t-bltg]

However OP's example errors on current PlotUtils and latest Plots. Will try to fix.