OPTION conv_crit1d-12

  Convergence criterion (default 1d-10).

OPTION maxrounds500

  Maximum rounds (default 5000).

OPTION constant_var 5 1 2

  The effect number (5), the first trait number (1), and the second trait number (2), implying the covariance between traits 1 and 2 for effect 5.

OPTION SNP_file snp

  Specify the SNP file name to use genotype data.

    Even when there is no variance, remlf90 will estimate a positive variance (in the parameter space), which will be determined by the starting value. If you are not sure if there is any variance, use a small starting value like 0.1 or 0.01. If the estimate does not change, probably there is no variance, so check your parameter file, model, and/or data again. Also, if airemlf90 does not converge but remlf90 converges with the same dataset, rerun remlf90 with a small starting value. The estimate could be artifact.