[scikit-learn] Which sparse matrix should be use for fit?

[Peng Yu]

https://scikit-learn.org/stable/modules/svm.html

Of the svm classes mentioned above, which sparse matrixes are
appropriate to be used with them?

https://docs.scipy.org/doc/scipy/reference/generated/scipy.sparse.csr_matrix.html#scipy.sparse.csr_matrix

It is not very clear what matrix operations are used in fit(), so I
can not tell what sparse matrixes should be used. Thanks.

-- 
Regards,
Peng