PyError

[azev77]

Stanford teaches intro to ML w/ Julia: http://ee104.stanford.edu/lectures.html
The program: house.jl calls houseplots.jl breaks when plotting w/ message:

PyError ($(Expr(:escape, :(ccall(#= C:\Users\azevelev\.julia\packages\PyCall\zqDXB\src\pyfncall.jl:43 =# @pysym(:PyObject_Call), PyPtr, (PyPtr, PyPtr, PyPtr), o, pyargsptr, kw))))) <class 'FileNotFoundError'>
FileNotFoundError(2, 'No such file or directory')
  File "C:\Users\azevelev\.julia\conda\3\lib\site-packages\matplotlib\pyplot.py", line 729, in savefig
    res = fig.savefig(*args, **kwargs)
  File "C:\Users\azevelev\.julia\conda\3\lib\site-packages\matplotlib\figure.py", line 2180, in savefig
    self.canvas.print_figure(fname, **kwargs)
  File "C:\Users\azevelev\.julia\conda\3\lib\site-packages\matplotlib\backend_bases.py", line 2091, in print_figure
    **kwargs)
  File "C:\Users\azevelev\.julia\conda\3\lib\site-packages\matplotlib\backends\backend_pdf.py", line 2496, in print_pdf
    file = PdfFile(filename, metadata=metadata)
  File "C:\Users\azevelev\.julia\conda\3\lib\site-packages\matplotlib\backends\backend_pdf.py", line 432, in __init__
    fh, opened = cbook.to_filehandle(filename, "wb", return_opened=True)
  File "C:\Users\azevelev\.julia\conda\3\lib\site-packages\matplotlib\cbook\__init__.py", line 432, in to_filehandle
    fh = open(fname, flag, encoding=encoding)


Stacktrace:
 [1] pyerr_check at C:\Users\azevelev\.julia\packages\PyCall\zqDXB\src\exception.jl:60 [inlined]
 [2] pyerr_check at C:\Users\azevelev\.julia\packages\PyCall\zqDXB\src\exception.jl:64 [inlined]
 [3] _handle_error(::String) at C:\Users\azevelev\.julia\packages\PyCall\zqDXB\src\exception.jl:81
 [4] macro expansion at C:\Users\azevelev\.julia\packages\PyCall\zqDXB\src\exception.jl:95 [inlined]
 [5] #110 at C:\Users\azevelev\.julia\packages\PyCall\zqDXB\src\pyfncall.jl:43 [inlined]
 [6] disable_sigint at .\c.jl:446 [inlined]
 [7] __pycall! at C:\Users\azevelev\.julia\packages\PyCall\zqDXB\src\pyfncall.jl:42 [inlined]
 [8] _pycall!(::PyCall.PyObject, ::PyCall.PyObject, ::Tuple{String}, ::Int64, ::Ptr{Nothing}) at C:\Users\azevelev\.julia\packages\PyCall\zqDXB\src\pyfncall.jl:29
 [9] _pycall! at C:\Users\azevelev\.julia\packages\PyCall\zqDXB\src\pyfncall.jl:11 [inlined]
 [10] #pycall#116 at C:\Users\azevelev\.julia\packages\PyCall\zqDXB\src\pyfncall.jl:83 [inlined]
 [11] pycall at C:\Users\azevelev\.julia\packages\PyCall\zqDXB\src\pyfncall.jl:83 [inlined]
 [12] savefig(::String; kws::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at C:\Users\azevelev\.julia\packages\PyPlot\XHEG0\src\PyPlot.jl:177
 [13] savefig at C:\Users\azevelev\.julia\packages\PyPlot\XHEG0\src\PyPlot.jl:174 [inlined]
 [14] save at C:\Users\azevelev\Dropbox\COMPUTATION\_QE_Moll\ML\Stanford\houseplots.jl:23 [inlined]
 [15] plotregpath(::Array{Float64,1}, ::Array{Float64,1}, ::Array{Float64,1}, ::String) at C:\Users\azevelev\Dropbox\COMPUTATION\_QE_Moll\ML\Stanford\houseplots.jl:40
 [16] plotridge(::Array{Array{Float64,2},1}, ::Array{Float64,1}, ::Array{Float64,1}, ::Array{Float64,1}, ::String) at C:\Users\azevelev\Dropbox\COMPUTATION\_QE_Moll\ML\Stanford\houseplots.jl:29
 [17] houseplots(::Array{String,2}, ::Array{String,1}, ::Array{Array{Float64,2},1}, ::Array{Float64,1}, ::Array{Float64,1}, ::Array{Float64,1}, ::Array{Float64,2}, ::Array{Float64,1}, ::Array{Float64,2}, ::Array{Float64,2}) at C:\Users\azevelev\Dropbox\COMPUTATION\_QE_Moll\ML\Stanford\houseplots.jl:80
 [18] main() at .\In[8]:25
 [19] macro expansion at .\util.jl:175 [inlined]
 [20] top-level scope at .\In[8]:28

[stevengj]

"No such file or directory" is being thrown by a savefig call, according to the traceback. Maybe you are trying to save to a directory that doesn't exist?

In particular, it looks like houseplots.jl calls plt.savefig(plotname(name)), but plotname(x) returns "graphics/$(fname)_$(basename2).$(extension)". So I'm guessing that the graphics directory doesn't exist; maybe you need to run mkpath("graphics")?

Anyway, this doesn't seem like a problem with PyCall per se. If you have usage questions or need help debugging your code, a better place to post is https://discourse.julialang.org/