function sign$1(x) {
	  // TODO(cais): Move to the core.
	  return tidy(function () {
	    var zerosLikeX = zerosLike(x);
	    var onesLikeX = onesLike(x);
	    return where(equal(x, zerosLikeX), zerosLikeX, where(greater(x, zerosLike(x)), onesLikeX, mul(-1, onesLikeX)));
	  });
	}
Compute the sign Tensor of an input Tensor.

Elements of the input `tf.Tensor` that are === 0 are mapped to 0.
Elements of the input `tf.Tensor` that are > 0 are mapped to 1.
Elements of the input `tf.Tensor` that are < 0 are mapped to -1.

@param x Input `tf.Tensor`.
@return The sign `tf.Tensor`.