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Many inputs to `MPSNNGraph::encodeBatchToCommandBuffer`
I understand we can use MPSImageBatch as input to [MPSNNGraph encodeBatchToCommandBuffer: ...] method. That being said, all inputs to the MPSNNGraph need to be encapsulated in a MPSImage(s). Suppose I have an machine learning application that trains/infers on thousands of input data where each input has 4 feature channels. Metal Performance Shaders is chosen as the primary AI backbone for real-time use. Due to the nature of encodeBatchToCommandBuffer method, I will have to create a MTLTexture first as a 2D texture array. The texture has pixel width of 1, height of 1 and pixel format being RGBA32f. The general set up will be: #define NumInputDims 4 MPSImageBatch * infBatch = @[]; const uint32_t totalFeatureSets = N; // Each slice is 4 (RGBA) channels. const uint32_t totalSlices = (totalFeatureSets * NumInputDims + 3) / 4; MTLTextureDescriptor * descriptor = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat: MTLPixelFormatRGBA32Float width: 1 height: 1 mipmapped: NO]; descriptor.textureType = MTLTextureType2DArray descriptor.arrayLength = totalSlices; id<MTLTexture> texture = [mDevice newTextureWithDescriptor: descriptor]; // bytes per row is `4 * sizeof(float)` since we're doing one pixel of RGBA32F. [texture replaceRegion: MTLRegionMake3D(0, 0, 0, 1, 1, totalSlices) mipmapLevel: 0 withBytes: inputFeatureBuffers[0].data() bytesPerRow: 4 * sizeof(float)]; MPSImage * infQueryImage = [[MPSImage alloc] initWithTexture: texture featureChannels: NumInputDims]; infBatch = [infBatch arrayByAddingObject: infQueryImage]; The training/inference will be: MPSNNGraph * mInferenceGraph = /*some MPSNNGraph setup*/; MPSImageBatch * returnImage = [mInferenceGraph encodeBatchToCommandBuffer: commandBuffer sourceImages: @[infBatch] sourceStates: nil intermediateImages: nil destinationStates: nil]; // Commit and wait... // Read the return image for the inferred result. As you can see, the setup is really ad hoc - a lot of 1x1 pixels just for this sole purpose. Is there any better way I can achieve the same result while still on Metal Performance Shaders? I guess a further question will be: can MPS handle general machine learning cases other than CNN? I can see the APIs are revolved around convolution network, both from online documentations and header files. Any response will be helpful, thank you.
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Oct ’24
Scale a view based on its content's aspect ratio
Say I have a View with an ImageView in it, how do I limit the main view's resizing so that it only resizes along the aspect ratio of the ImageView? When I resize, I'd expect the image resizes as well. Some vanilla snippet: struct ContentView: View { @State private var width = 400.0 @State private var height = 300.0 @State private var image: Image? var body: some View { VStack { image? .resizable() .scaledToFit() .gesture(spatialTap) } } }
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Dec ’23