Fix a hang in write_matrix_market_csc #76
+17
−11
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…tter::chunk::next_chunk. Trying to calculate the chunk size with nnz_per_columns being 0, which may happen for sparse arrays with no explicit values, results in an undefined behavior (division by 0).
…dependent of the number of explicit values.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Calling
write_matrix_market_cscon a sparse array with no explicit values hangs indefinitely. This is caused by the fact that insidecsc_formatter::chunk::next_chunk, there is a division bynnz_per_column, which happens to be0.for such arrays.The fix I propose here is to set
ptr_chunk_endto the end of range in the problematic case, avoiding division by zero.An alternative fix could be to call
write_bodyinsidewrite_matrix_market_csconly ifnnz > 0, but it doesn't really solve the problem within thecsc_formatter.I also updated unit tests to cover the case of a csc matrix with no explicit values and non-zero dimensions.