public (NSArray <MPSImage> Inputs, NSArray <MPSState> Losses) GetRandomBatch(IMTLDevice device, int batchSize)
{
var trainImageDesc = MPSImageDescriptor.GetImageDescriptor(
MPSImageFeatureChannelFormat.Unorm8,
ImageSize, ImageSize, 1,
1,
MTLTextureUsage.ShaderWrite | MTLTextureUsage.ShaderRead);
var trainBatch = new List <MPSImage> ();
var lossStateBatch = new List <MPSState> ();
unsafe
{
fixed(byte *imagesPointer = imagesData)
fixed(byte *labelsPointer = labelsData)
{
for (var i = 0; i < batchSize; i++)
{
var randomIndex = random.Next(numImages);
var trainImage = new MPSImage(device, trainImageDesc)
{
Label = "TrainImage" + i
};
trainBatch.Add(trainImage);
var trainImagePointer = imagesPointer + ImagesPrefixSize + randomIndex * ImageSize * ImageSize;
trainImage.WriteBytes((IntPtr)trainImagePointer, MPSDataLayout.HeightPerWidthPerFeatureChannels, 0);
var labelPointer = labelsPointer + LabelsPrefixSize + randomIndex;
var labelsValues = new float[12];
labelsValues[*labelPointer] = 1;
fixed(void *p = labelsValues)
{
using var data = NSData.FromBytes((IntPtr)p, 12 * sizeof(float));
var desc = MPSCnnLossDataDescriptor.Create(
data, MPSDataLayout.HeightPerWidthPerFeatureChannels, new MTLSize(1, 1, 12));
var lossState = new MPSCnnLossLabels(device, desc);
lossStateBatch.Add(lossState);
}
}
}
}
return(NSArray <MPSImage> .FromNSObjects(trainBatch.ToArray()),
NSArray <MPSState> .FromNSObjects(lossStateBatch.ToArray()));
}
public void Metal()
{
TestRuntime.AssertDevice();
TestRuntime.AssertXcodeVersion(10, 0);
device = MTLDevice.SystemDefault;
// some older hardware won't have a default
if (device == null || !MPSKernel.Supports(device))
{
Assert.Inconclusive("Metal is not supported");
}
cache = NSArray <MPSImage> .FromNSObjects(
new MPSImage (device, MPSImageDescriptor.GetImageDescriptor(MPSImageFeatureChannelFormat.Float32, 224, 224, 3)),
new MPSImage (device, MPSImageDescriptor.GetImageDescriptor(MPSImageFeatureChannelFormat.Float32, 224, 224, 3)),
new MPSImage (device, MPSImageDescriptor.GetImageDescriptor(MPSImageFeatureChannelFormat.Float32, 224, 224, 3)),
new MPSImage (device, MPSImageDescriptor.GetImageDescriptor(MPSImageFeatureChannelFormat.Float32, 224, 224, 3)),
new MPSImage (device, MPSImageDescriptor.GetImageDescriptor(MPSImageFeatureChannelFormat.Float32, 224, 224, 3))
);
}