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Bug 1330 - m_shiftOffset in CholmodBase should be double not RealScalar
Summary: m_shiftOffset in CholmodBase should be double not RealScalar
Alias: None
Product: Eigen
Classification: Unclassified
Component: Sparse (show other bugs)
Version: 3.2
Hardware: x86 - 64-bit Linux
: Normal Compilation Problem
Assignee: Nobody
Depends on:
Blocks: 3.3
  Show dependency treegraph
Reported: 2016-10-18 13:15 UTC by philip.avery
Modified: 2016-11-03 09:31 UTC (History)
3 users (show)

example program that exposes the issue (199 bytes, text/x-c++src)
2016-10-18 13:15 UTC, philip.avery
no flags Details

Description philip.avery 2016-10-18 13:15:29 UTC
Created attachment 748 [details]
example program that exposes the issue

I have attached a small program in which the cholmod support module is used with single precision floating point. This does not compile with gcc 6.2. The error message is:
eigen/Eigen/src/CholmodSupport/CholmodSupport.h:279:26: error: cannot convert ‘Eigen::CholmodBase<Eigen::SparseMatrix<float>, 2, Eigen::CholmodSimplicialLLT<Eigen::SparseMatrix<float>, 2> >::RealScalar* {aka float*}’ to ‘double*’ for argument ‘2’ to ‘int cholmod_factorize_p(cholmod_sparse*, double*, int*, std::size_t, cholmod_factor*, cholmod_common*)’
       cholmod_factorize_p(&A, m_shiftOffset, 0, 0, m_cholmodFactor, &m_cholmod);

The issue can be fixed by changing m_shiftOffset to double rather than RealScalar. I am using version 4.5.3 of the suitesparse library from the ubuntu 16.10 repository.
Comment 1 Christoph Hertzberg 2016-10-20 13:50:50 UTC
Just a small update: I confirm that this is obviously wrong and changing it as suggested makes it compile.
However, I tried extending the unit tests to float afterwards, and I always get failed decompositions for float or complex<float>.
I'm on Ubuntu 14.10 with libsuitesparse 3.1.0 -- maybe that is already the reason for the failure. (I'll try again on an ubuntu 16.10, as soon as I find the time)

I also tested RowMajor and StorageIndex=long matrices which fail (for reasons I think I know how to fix, however).
Comment 2 Gael Guennebaud 2016-11-03 09:31:32 UTC
Changeset:   462c06acd766
User:        ggael
Date:        2016-11-03 09:21:59+00:00
Summary:     Bug 1330: Cholmod supports double precision only, so let's trigger a static assertion if the scalar type does not match this requirement.


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