Ways to use SageMath

On my computer

• the sage REPL or command-line-interface
  • launch Sage in a terminal, wait for the sage: prompt
  • type a command then hit the ENTER or RETURN key, get output
• the Jupyter Notebook with the Sage kernel
  • ways to launch it
    • in a terminal, type sage -n jupyter
    • or use a launcher such as
      • the macOS "Sage app"
      • the Windows launcher
      • a desktop launcher for Linux
• JupyterLab
  • install using sage --pip install jupyterlab
  • then in the terminal run sage -n jupyterlab
• the legacy SageNB notebook
  • ways to launch it
    • in a terminal, type sage -n sagenb
    • or in the Sage REPL, type notebook()
    • or use a launcher
• run a command with sage -c
  • example: in a terminal, run sage -c "print(2 + 2)"
• run a file with extension .py or .sage
  • put the commands in a file such as myfile.sage or myfile.py
  • in the terminal, run sage myfile.sage or sage myfile.py
  • difference between .sage and .py files
    • for .sage files, the Sage preparser will be used
    • for .py files, the Sage preparser will not be used
• use external files
  • commands
    • load, runfile, attach, %load, %runfile, %attach
    • examples
      • suppose the file myfile.sage contains def sq(a): return a*a
      • in the terminal, run sage -c "load('myfile.sage'); print(sq(2))"
• from another program
  • SageTeX, a LaTeX package to use Sage within TeX/LaTeX documents
  • PreTeXt
  • Cantor
  • TeXmacs
  • see also Interfaces to SageMath in other software
• use OpenMath and SCSCP to exchange mathematical objects with other mathematics software; work in progress, see
  • Sage Trac ticket 19971: Provide OpenMath interface
  • Sage Trac ticket 19970: Provide SCSCP interface

Online

• SageCell
  • one-off computations on SageCell page
  • use it to include compute cells in a webpage
  • use it with PreTeXt
• CoCalc
  • see dedicated item below
• JupyterHub
  • there are some deployments of JupyterHub which offer the Sage kernel
• mybinder
  • there are some mybinder instances that include Sage
• Sage Notebook servers
  • there some deployments of the SageNB notebook; the one formerly at sagenb.org is no longer active

CoCalc

• in a CoCalc terminal, run sage for the Sage REPL
• use sage_select to select which version of Sage to use by default
• CoCalc Sage worksheets (.sagews)
• Jupyter Notebook worksheets (.ipynb)
  • using CoCalc's version of the Jupyter Notebook
  • using the Classic Jupyter Notebook
    • go to Project preferences and launch Classic Jupyter Notebook; this will open a separate browser tab which will connect to your project using the classic Jupyter Notebook protocol;
    • allows to use Jupyter Notebook extensions that are not yet implemented in "CoCalc Jupyter", such as widgets, RISE, ...

Sage: file formats, data formats

• common file extensions
  • .py, .sage, .pyx, .spyx, ...
  • .sobj
  • SageNB notebook worksheets: .sws
  • CoCalc Sage worksheets: .sagews
  • .rst, .txt, .html
• converters
  • rst2ipynb, ...
• viewing, saving, copying, transferring worksheets

Run shell commands from within sage

• any command starting with ! is executed as a shell command
• many basic shell commands are available in IPython without !: ls, cd, pwd...
• see also the Python modules os and sys

Read from, write to, append to file

• this uses standard Python functionality
• 'r' for read, 'w' for write (overwriting file), 'a' for append

• read from file, all at once or line by line

  with open('/path/to/file.txt', 'r') as f:
      s = f.read()
  
  with open('/path/to/file.txt', 'r') as f:
      for line in f:
          <do something with line>
  

• write to file, bit by bit or line by line

  with open('/path/to/file.txt', 'a') as f:
      f.write('blah')
      f.writelines(['haha', 'hehe', 'hihi'])
  

• see also the csv module for "comma-separated-values" data files

If one wants to use Sage in Jupyterlab on macOS Catalina 10.15.1 (19B88), this worked for me:

1. download Sage binaries
2. unpack download
3. move SAGE_ROOT to the desired location
4. set SAGE_ROOT and any other environment variables (e.g. SAGE_KEEP_BUILT_SPKGS) in ~/.zshrc
    (a) export SAGE_KEEP_BUILT_SPKGS="yes" 
    (b) export SAGE_NUM_THREADS=3
    (c) export SAGE_ROOT="$HOME/SageMath"
5. Update $PATH by editing /etc/paths Note: You’ll need to use SUDO.
    <$HOME>/SageMath/local/bin
    /usr/local/bin
    /usr/local/sbin
    /usr/bin
    /bin
    /usr/sbin
    /sbin
    <$HOME>/SageMath
6. cd $SAGE_ROOT && ./sage -i openssl && ./sage -f python3 && make ssl && sage –pip3 install jupyterlab

when all this is done, sage -n jupyterlab, should work.

Update: Avoid updating Python packages using pip. I broke the sage kernal in jupyterlab doing this.