Check whether any of the state variables are significantly negative and emit suitable warnings.
checkSolution(output, numSpecies, numStages, numStrains, ntol)Model output from popModel
Number of species
Number of life stages
Number of strains for each species
Negative tolerance value (i.e. a warning is produced if variable<-(ntol*max(variable))). The larger ntol is, the larger the negative values that are tolerated.
Nothing if there are no problems with the output, otherwise warnings are generated