def get_response_content(fs):
# get the codon distribution
codons = Codon.g_sorted_non_stop_codons
distribution = SnippetUtil.get_distribution(fs.weights, 'codon', codons)
# get the rate matrix defined by the weights and kappa and omega
r = RateMatrix.get_gy94_rate_matrix(distribution, fs.kappa, fs.omega)
# show the rate matrix in convenient text form
out = StringIO()
for ca in codons:
print >> out, '\t'.join(str(r[(ca, cb)]) for cb in codons)
return out.getvalue()
