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tfp.distributions.fill_triangular_inverse

Creates a vector from a (batch of) triangular matrix.

tfp.distributions.fill_triangular_inverse(
    x,
    upper=False,
    name=None
)

Defined in python/internal/distribution_util.py.

The vector is created from the lower-triangular or upper-triangular portion depending on the value of the parameter upper.

If x.shape is [b1, b2, ..., bB, n, n] then the output shape is [b1, b2, ..., bB, d] where d = n (n + 1) / 2.

Example:

fill_triangular_inverse(
  [[4, 0, 0],
   [6, 5, 0],
   [3, 2, 1]])

# ==> [1, 2, 3, 4, 5, 6]

fill_triangular_inverse(
  [[1, 2, 3],
   [0, 5, 6],
   [0, 0, 4]], upper=True)

# ==> [1, 2, 3, 4, 5, 6]

Args:

  • x: Tensor representing lower (or upper) triangular elements.
  • upper: Python bool representing whether output matrix should be upper triangular (True) or lower triangular (False, default).
  • name: Python str. The name to give this op.

Returns:

  • flat_tril: (Batch of) vector-shaped Tensor representing vectorized lower (or upper) triangular elements from x.