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Bug 1236

Summary:	[SparseSparseProductWithPruning] Integer overflow in ratioColRes estimation
Product:	Eigen	Reporter:	Jérémie <jeremie.dumas>
Component:	Sparse	Assignee:	Nobody <eigen.nobody>
Status:	RESOLVED FIXED
Severity:	Unknown	CC:	chtz, gael.guennebaud
Priority:	Normal
Version:	3.2
Hardware:	x86 - 64-bit
OS:	All
Whiteboard:

Description Jérémie 2016-05-26 10:14:24 UTC

Hi,


On Eigen's latest stable version (3.2.8), I am encountering a signed integer overflow when using Sparse / Sparse products with pruning, namely on the following line:

  double ratioColRes = double(estimated_nnz_prod)/double(lhs.rows()*rhs.cols());

And then the problem reported at the exectution:

  SparseSparseProductWithPruning.h:51:68: runtime error: signed integer overflow: 56224 * 56224 cannot be represented in type 'int [3]'

Now, I don't know what this 'int [3]' means, but this product would fit in a 'long long' or a double, so I guess the overflow could be avoided.

Comment 1 Gael Guennebaud 2016-05-26 15:52:38 UTC

Thanks for the report, I've simply moved the conversion to double before the product.
devel: https://bitbucket.org/eigen/eigen/commits/caa3c3993517/
3.2:   https://bitbucket.org/eigen/eigen/commits/282ed0ab80a9/

Comment 2 Nobody 2019-12-04 15:52:45 UTC

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