CODEWITHSUNDEEP
c++staticasserteigen
ButterDog
ButterDog

Reputation: 5225

Finding the source of a failed static assertion on Eigen

I'm trying to compile a -quite large- code base which has some dependencies to Eigen. Doing so, I got the following error: error C2338: THE_BRACKET_OPERATOR_IS_ONLY_FOR_VECTORS__USE_THE_PARENTHESIS_OPERATOR_INSTEAD that originates here:

//    Eigen\src\Core\DenseCoeffsBase.h


/** \returns a reference to the coefficient at given index.
  *
  * This method is allowed only for vector expressions, and for matrix expressions having the LinearAccessBit.
  *
  * \sa operator[](Index) const, operator()(Index,Index), x(), y(), z(), w()
  */

EIGEN_STRONG_INLINE Scalar&
operator[](Index index)
{
  #ifndef EIGEN2_SUPPORT
  EIGEN_STATIC_ASSERT(Derived::IsVectorAtCompileTime,
                      THE_BRACKET_OPERATOR_IS_ONLY_FOR_VECTORS__USE_THE_PARENTHESIS_OPERATOR_INSTEAD)
  #endif
  eigen_assert(index >= 0 && index < size());
  return derived().coeffRef(index);
}

As the Eigen dependencies are all over the code, how can I find the line triggering this error? (obviously, there is a line of code accessing an Eigen matrix using [], somewhere, this is the line I'm looking for).

Upvotes: 2

Views: 7510

Answers (1)

Hao-HUST
Hao-HUST

Reputation: 19

Yes, I also encountered similar problem. I defined a matrix as:

Eigen::MatrixXf minor2x2 (2,2). When the matrix minor2x2 was initialized like that : 

minor2x2[0] = 1.0f;
minor2x2[1] = 1.0f;
minor2x2[2] = 1.0f;
minor2x2[3] = 1.0f;

The same error was triggered. The solution to the problem is to replace minor2x2[i] to minor2x2(i). I think finding Eigen::Matrix perhaps is helpful.

Upvotes: 1

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