Conditional computation aims to increase the size and accuracy of a network, at a small increase in inference cost. Previous hard-routing models explicitly route the input to a subset of experts. We propose soft conditional computation, which, in contrast, utilizes all experts while still permitting efficient inference through parameter routing. Concretely, for a given convolutional layer, we wish to compute a linear combination of @math experts @math , where @math are functions of the input learned through gradient descent. A straightforward evaluation requires @math convolutions. We propose an equivalent form of the above computation, @math , which requires only a single convolution. We demonstrate the efficacy of our method, named CondConv, by scaling up the MobileNetV1, MobileNetV2, and ResNet-50 model architectures to achieve higher accuracy while retaining efficient inference. On the ImageNet classification dataset, CondConv improves the top-1 validation accuracy of the MobileNetV1(0.5x) model from 63.8 to 71.6 while only increasing inference cost by 27 . On COCO object detection, CondConv improves the minival mAP of a MobileNetV1(1.0x) SSD model from 20.3 to 22.4 with just a 4 increase in inference cost.
. In recent work, SplineNets @cite_26 propose the use of B-splines to model learnable weights for continuous neural decision graphs. Compared to SplineNets, explores more complex weight-generating functions.
@cite_26
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We present SplineNets, a practical and novel approach for using conditioning in convolutional neural networks (CNNs). Our method dramatically reduces runtime complexity and computation costs of CNNs, while maintaining or even increasing accuracy. SplineNets employ a unified loss function with a desired level of smoothness over both the network and decision parameters, while allowing for sparse activation of a subset of nodes for individual samples. Thus, functions of SplineNets are both dynamic (i.e., conditioned on the input) and hierarchical (i.e., conditioned on the computational path). In particular, we embed weights of functions on smooth, low dimensional manifolds parameterized by compact B-splines, and define decisions as choosing a position on these hyper-surfaces. We further show that by maximizing the mutual information between these latent coordinates and data or its labels, the network can be optimally utilized and specialized. Experiments on various image classification datasets show the power of this new paradigm over regular CNNs.