# init(device:convolutionDescriptor:kernelWeights:biasTerms:flags:) Initializes a convolution kernel. ``` init(device: any MTLDevice, convolutionDescriptor: MPSCNNConvolutionDescriptor, kernelWeights: UnsafePointer, biasTerms: UnsafePointer?, flags: MPSCNNConvolutionFlags) ``` ## Parameters `device` The device on which this kernel will run. `convolutionDescriptor` A pointer to a valid convolution descriptor. `kernelWeights` A pointer to a weights array. Each entry is a float value. The number of entries is equal to [`inputFeatureChannels`](/documentation/MetalPerformanceShaders/MPSCNNConvolutionDescriptor/inputFeatureChannels) `*` [`outputFeatureChannels`](/documentation/MetalPerformanceShaders/MPSCNNConvolutionDescriptor/outputFeatureChannels) `*` [`kernelHeight`](/documentation/MetalPerformanceShaders/MPSCNNConvolutionDescriptor/kernelHeight) `*` [`kernelWidth`](/documentation/MetalPerformanceShaders/MPSCNNConvolutionDescriptor/kernelWidth) . The layout of the filter weight is arranged so that it can be reinterpreted as a 4D tensor (array) `weight[outputChannels][kernelHeight][kernelWidth][inputChannels/groups]` Weights are converted to half float precision ( `fp16` ) internally for best performance. `biasTerms` A pointer to bias terms to be applied to the convolution output. Each entry is a float value. The number of entries is the number of output feature maps. `flags` Currently unused. This value must be [`MPSCNNConvolutionFlags.none`](/documentation/MetalPerformanceShaders/MPSCNNConvolutionFlags/none) . ## Return Value A valid [`MPSCNNConvolution`](/documentation/MetalPerformanceShaders/MPSCNNConvolution) object or `nil`, if failure. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)