I am trying to use SymPy package to deal with symbolic math. For example:
using SymPy
x, y, z = symbols("x y z")
z=(x^2+y^2)/(y^2+1);
However, the error appears:
x, y, z = symbols("x y z")
ERROR: ArgumentError: ref of NULL PyObject
Anyone can help me please?
Working for me:
_
_ _ _(_)_ | Documentation: https://docs.julialang.org
(_) | (_) (_) |
_ _ _| |_ __ _ | Type "?" for help, "]?" for Pkg help.
| | | | | | |/ _` | |
| | |_| | | | (_| | | Version 1.5.0 (2020-08-01)
_/ |\__'_|_|_|\__'_| | Official https://julialang.org/ release
|__/ |
julia> using SymPy
julia> x, y, z = symbols("x y z")
(x, y, z)
julia> z=(x^2+y^2)/(y^2+1)
2 2
x + y
───────
2
y + 1
Perhaps your Python installation is broken?
Operating system?
Are you using Conda?
Citation:
To force Julia to use its own Python distribution, via Conda, simply set ENV["PYTHON"] to the empty string "" and re-run Pkg.build("PyCall") .
I am with windows
Julia version 1.0.4
I re run Pkg.build(“PyCall”) but nothing yet!
Can I remove all packages and reinstall all?
Did you execute:
before executing
Pkg.build("PyCall")
That is important.
Furthermore, if it is possible for you, install Julia 1.5 instead of 1.0.4 . It works much more smoothly.
Nothing yet…
See:
It should be possible to run any code that works with 1.0.4 on 1.5.
But note that you can install version 1.5 at the same time as 1.0.4 and choose which version you want to run.
Version 1.5 has a lot of advantages, and packages (that are maintained) are probably more likely to work correctly.
Please execute:
ENV["PYTHON"]=""
Pkg.build("PyCall")
You did it in the wrong order.
Dear friend,
I did as you told me; installed version 1.5 and ran ENV[“PYTHON”]=“” and then Pkg.build(“PyCall”).
But nothing happens, it stays for hours “installing”.
Do you know what this could be, please?
Did you try first just adding and running the SymPy package?
Please try with Julia instead of JuliaPro
Yes, it can take a long amount of time.
But you can see the progress by looking at the logfile:
c:\Users\Usuario.julia\packages\PyCall\zqDXB\deps\build.log
I guess I spelled your user name wrong, it seams to have special characters in it.
Not sure how to look at a log file in windows, in linux you just do:
tail -f <logfilename>
Perhaps you can try to open the log file with your favorite editor.
Special chacters avoid anything?
I’ve installed all again. I’ll try to install now. Thank you so much
Are you using Atom?
Try to avoid that if you are debugging a problem, because it introduces addtional problems.
Did you:
3. entered the package manager by pressing ]
4. run the command "up" to update the list of the packages
5. installed SymPy with the command
add SymPy
Did any of these steps result in an error?
If yes, are you perhaps behind a firewall?
Furthermore, what is the output of the command
status
while you are in the package manager?
For me I have the output:
(@v1.5) pkg> status
Status `~/.julia/environments/v1.5/Project.toml`
[6e4b80f9] BenchmarkTools v0.5.0
[336ed68f] CSV v0.7.7
[d749ddd5] DaemonMode v0.1.0 `https://github.com/dmolina/DaemonMode.jl#master`
[a93c6f00] DataFrames v0.21.6
[d330b81b] PyPlot v2.9.0
[2db162a6] QML v0.6.0
[24249f21] SymPy v1.0.27
(@v1.5) pkg>
It will be different for you, but might be important to know.Now press backspace and then
julia> using SymPy
But you did not follow the instructions to download the standard version of Julia from the download page pointed to by @ufechner7. You are still using Julia Pro, which is a different version that most people here are not familiar with.
