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Bug 986 - Mx0 * 0xN (zero size) matrix products
Summary: Mx0 * 0xN (zero size) matrix products
Alias: None
Product: Eigen
Classification: Unclassified
Component: Core - matrix products (show other bugs)
Version: 3.2
Hardware: x86 - 64-bit Mac OS
: Normal Feature Request
Assignee: Nobody
Depends on:
Reported: 2015-03-31 18:15 UTC by twan_koolen
Modified: 2015-04-01 17:27 UTC (History)
2 users (show)

Code segment demonstrating problems with Mx0 * 0xN matrix products (587 bytes, text/plain)
2015-03-31 18:15 UTC, twan_koolen
no flags Details

Description twan_koolen 2015-03-31 18:15:13 UTC
Created attachment 559 [details]
Code segment demonstrating problems with Mx0 * 0xN matrix products

Reading through the changelog, I was excited to see the line 'Enable Mx0 * 0xN matrix products' in version 3.2.3. I think there are still some issues however.

See the attached file. The output on my machine (compiled using clang) is:
Eigen version: 3.2.4

For x, y, and z I would expect a 6x1 matrix of zeros. However evaluating x = A * b results in a segfault and evaluating y = A * c results in an assertion error:
Assertion failed: (lhs.cols()>0 && "you are using a non initialized matrix"), function run, file /usr/local/include/eigen3/Eigen/src/Core/products/CoeffBasedProduct.h, line 428.
Comment 1 Gael Guennebaud 2015-03-31 22:52:47 UTC
Confirmed, expect that with the latest 3.2 and devel branches you do not get segfaults but either assertions or compilation failures. This is thus more a feature request.
Comment 3 twan_koolen 2015-04-01 17:27:56 UTC
Wow, that's great. Thanks for the quick response!

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