Fixed critical R CMD check failure observed in specific
environments (e.g., R-devel/ATLAS). The error, “requires numeric/complex
matrix/vector arguments,” occurred during matrix multiplication within
the variance estimation step of geemaee when handling
numerically singular or near-singular matrices.
Improved Numerical Robustness: Implemented defensive programming checks within internal variance estimation functions to handle edge cases where intermediate matrices become non-numeric or non-positive-definite due to precision differences across BLAS/LAPACK implementations. This prevents package crashes during variance calculation.