[#MATH-248] Multiplying sparse matrices is slow

Commons Math

Multiplying sparse matrices is slow

Created: 22/Feb/09 07:53 PM Updated: 23/Apr/09 02:26 AM

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Fix Version/s:

2.0

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Resolution Date:

05/Apr/09 04:54 PM

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The multiplication of sparse real matrices is very slow compared to real matrices: Ten times as slow for size 200, four times as slow for size 400. The time is independent of the number of nonzero entries, because the general algorithm inherited from AbstractRealMatrix is used. I suggest using a specialized multiplication algorithm for matrices that are "sparse enough", walking only over the nonzero entries in one of the matrices.

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Repository	Revision	Date	User	Message
ASF	#762117	Sun Apr 05 16:53:35 UTC 2009	luc	Greatly improved multiplication speed for sparse matrices Jira: ~~MATH-248~~
				Files Changed
				MODIFY /commons/proper/math/trunk/src/site/xdoc/changes.xml MODIFY /commons/proper/math/trunk/src/test/org/apache/commons/math/linear/SparseRealMatrixTest.java MODIFY /commons/proper/math/trunk/src/java/org/apache/commons/math/linear/SparseRealMatrix.java