CODEWITHSUNDEEP
c++eigen
joaocandre
joaocandre

Reputation: 1745

Eigen Assertion error at run time

I am compiling a program that uses several Eigen::MatrixXd methods, and while I get no errors when compiling it, running it I get the following error:

darwin-pi2: /usr/include/Eigen/src/Core/Assign.h:498: Derived& Eigen::DenseBase<Derived>::lazyAssign(const Eigen::DenseBase<OtherDerived>&) [with OtherDerived = Eigen::Matrix<double, -1, -1>; Derived = Eigen::Matrix<double, 15, 15, 0, 15, 15>]: Assertion `rows() == other.rows() && cols() == other.cols()' failed.

I guess it is something related to Eigen matrices, but I do not understand what Assertion rows() == other.rows() && cols() == other.cols()' failed means.

Upvotes: 2

Views: 6092

Answers (2)

GoingMyWay
GoingMyWay

Reputation: 17468

In matlab, the index of a matrix m starts from 1. But in eigen, it starts from 0. Show a simple example.

#include <iostream>
#include <Eigen/Dense>
using Eigen::MatrixXd;
int main()
{
  MatrixXd m(2,2);
  m(0,0) = 3;  //  INDEX starts from 0, not 1
  m(1,0) = 2.5;
  m(0,1) = -1;
  m(1,1) = m(1,0) + m(0,1);
  std::cout << m << std::endl;
}

For more information, click the docs.

Upvotes: 0

Potatoswatter
Potatoswatter

Reputation: 137770

Because Eigen::MatrixXd has dimensions determined at runtime, the compile-time size checks are all disabled and deferred until runtime.

In this case, it looks like you're assigning from a dynamic-size matrix to a 15x15 one. Try double-checking and debugging the size of that dynamic one.

Upvotes: 1

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