Undefined propagation kind.
Forward data propagation (training mode).
In this mode, primitives perform computations necessary for subsequent backward propagation.
Forward data propagation (inference mode).
In this mode, primitives perform only computations that are necessary for inference and omit computations that are necessary only for backward propagation.
Backward propagation (with respect to all parameters).
Backward data propagation.
Backward weights propagation.
Backward bias propagation.