def random_rescale_to_mahalanobis(self, x):
        """change `x` like for injection, all on genotypic level"""
        x -= self.mean
        if any(x):
            x *= sum(self.randn(len(x))**2)**0.5 / self.mahalanobis_norm(x)
        x += self.mean
        return x
change `x` like for injection, all on genotypic level