Tim Davis Profile picture
Prof. CS@TAMU. Fellow SIAM, ACM. For ethical issues with @Github and a possible path forward: https://t.co/WFGELT8u02

Oct 16, 2022, 6 tweets

@github copilot, with "public code" blocked, emits large chunks of my copyrighted code, with no attribution, no LGPL license. For example, the simple prompt "sparse matrix transpose, cs_" produces my cs_transpose in CSparse. My code on left, github on right. Not OK.

Sparse matrix addition, from github.com/DrTimothyAlden… but also reguritated by copilot with "// sparse matrix add, cs_". My code on left, github on right.

Other codes are slightly morphed. I could probably reproduce my entire sparse matrix libraries from simple prompts. My code on left (in the Terminal). Prompt is "sparse matrix elimination tree, cs_". Github on right.

Curious about the "cs_" in the prompt, I tried no function name, just "/* sparse matrix transpose in the style of Tim Davis */". And got my code again, slight tweaked. So the @github AI "knows" this is my code.

Try it. Compare with github.com/DrTimothyAlden…

@github Can someone else try this prompt in an empty C code:

/* sparse matrix transpose in the style of Tim Davis */

and post the result? Turn off the "use public code" option first, and restart VS, and wait 30 minutes (per their instructions). I want to make sure it's not just me...

@github I also got an this result starting with just the single prompt.

// sparse matrix transpose

and hitting tab many times, then control-enter. I get back all my own code, slightly tweaked. No "Tim Davis" in the prompt. No "cs_transpose" or even "cs_".

is this just me?

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