/// <summary>
/// Returns a new distribution instance (or populates an existing instance provided by a derived class) with batch dimensions expanded to
/// `batch_shape`. This method calls `torch.Tensor.expand()` on the distribution's parameters. As such, this does not allocate new
/// memory for the expanded distribution instance.
/// </summary>
/// <param name="batch_shape">Tthe desired expanded size.</param>
/// <param name="instance">new instance provided by subclasses that need to override `.expand`.</param>
public override distributions.Distribution expand(long[] batch_shape, distributions.Distribution instance = null)
{
if (instance != null && !(instance is Multinomial))
{
throw new ArgumentException("expand(): 'instance' must be a Multinomial distribution");
}
var newDistribution = ((instance == null) ?
new Multinomial(total_count, categorical.expand(batch_shape) as Categorical) :
instance) as Multinomial;
if (newDistribution == instance)
{
newDistribution.total_count = total_count;
newDistribution.categorical = categorical.expand(batch_shape) as Categorical;
newDistribution.batch_shape = newDistribution.categorical.batch_shape;
var ps = newDistribution.categorical.param_shape;
newDistribution.event_shape = new long[] { ps[ps.Length - 1] };
}
return(newDistribution);
}
