I'm using a custom create ML model to classify the movement of a user's hand in a game,
The classifier has 3 different spell movements, but my code constantly predicts all of them at an equal 1/3 probability regardless of movement which leads me to believe my code isn't correct (as opposed to the model) which in CreateML at least gives me a heavily weighted prediction
My code is below.
On adding debug prints everywhere all the data looks good to me and matches similar to my test CSV data
So I'm thinking my issue must be in the setup of my model code?
/// Feeds samples into the model and keeps a sliding window of the last N frames.
final class WandGestureStreamer {
static let shared = WandGestureStreamer()
private let model: SpellActivityClassifier
private var samples: [Transform] = []
private let windowSize = 100 // number of frames the model expects
/// RNN hidden state passed between inferences
private var stateIn: MLMultiArray
/// Last transform dropped from the window for continuity
private var lastDropped: Transform?
private init() {
let config = MLModelConfiguration()
self.model = try! SpellActivityClassifier(configuration: config)
// Initialize stateIn to the model’s required shape
let constraint = self.model.model.modelDescription
.inputDescriptionsByName["stateIn"]!
.multiArrayConstraint!
self.stateIn = try! MLMultiArray(shape: constraint.shape, dataType: .double)
}
/// Call once per frame with the latest wand position (or any feature vector).
func appendSample(_ sample: Transform) {
samples.append(sample)
// drop oldest frame if over capacity, retaining it for delta at window start
if samples.count > windowSize {
lastDropped = samples.removeFirst()
}
}
func classifyIfReady(threshold: Double = 0.6) -> (label: String, confidence: Double)? {
guard samples.count == windowSize else { return nil }
do {
let input = try makeInput(initialState: stateIn)
let output = try model.prediction(input: input)
// Save state for continuity
stateIn = output.stateOut
let best = output.label
let conf = output.labelProbability[best] ?? 0
// If you’ve recognized a gesture with high confidence:
if conf > threshold {
return (best, conf)
} else {
return nil
}
} catch {
print("Error", error.localizedDescription, error)
return nil
}
}
/// Constructs a SpellActivityClassifierInput from recorded wand transforms.
func makeInput(initialState: MLMultiArray) throws -> SpellActivityClassifierInput {
let count = samples.count as NSNumber
let shape = [count]
let timeArr = try MLMultiArray(shape: shape, dataType: .double)
let dxArr = try MLMultiArray(shape: shape, dataType: .double)
let dyArr = try MLMultiArray(shape: shape, dataType: .double)
let dzArr = try MLMultiArray(shape: shape, dataType: .double)
let rwArr = try MLMultiArray(shape: shape, dataType: .double)
let rxArr = try MLMultiArray(shape: shape, dataType: .double)
let ryArr = try MLMultiArray(shape: shape, dataType: .double)
let rzArr = try MLMultiArray(shape: shape, dataType: .double)
for (i, sample) in samples.enumerated() {
let previousSample = i > 0 ? samples[i - 1] : lastDropped
let model = WandMovementRecording.DataModel(transform: sample, previous: previousSample)
// print("model", model)
timeArr[i] = NSNumber(value: model.timestamp)
dxArr[i] = NSNumber(value: model.dx)
dyArr[i] = NSNumber(value: model.dy)
dzArr[i] = NSNumber(value: model.dz)
let rot = model.rotation
rwArr[i] = NSNumber(value: rot.w)
rxArr[i] = NSNumber(value: rot.x)
ryArr[i] = NSNumber(value: rot.y)
rzArr[i] = NSNumber(value: rot.z)
}
return SpellActivityClassifierInput(
dx: dxArr, dy: dyArr, dz: dzArr,
rotation_w: rwArr, rotation_x: rxArr, rotation_y: ryArr, rotation_z: rzArr,
timestamp: timeArr,
stateIn: initialState
)
}
}
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I have been using "apple" to test foundation models.
I thought this is local, but today the answer changed - half way through explanation, suddenly guardrailViolation error was activated! And yesterday, all reference to "Apple II", "Apple III" now refers me to consult apple.com!
Does foundation models connect to Internet for answer? Using beta 3.
Topic:
Machine Learning & AI
SubTopic:
Foundation Models
When I use ChatGPT in Xcode, the following error is displayed:
It was working fine before, but suddenly it became like this, without changing any configuration. Why?
Topic:
Machine Learning & AI
SubTopic:
Apple Intelligence
Hi everyone,
I believe I’ve encountered a potential bug or a hardware alignment limitation in the Core ML Framework / ANE Runtime specifically affecting the new Stateful API (introduced in iOS 18/macOS 15).
The Issue:
A Stateful mlprogram fails to run on the Apple Neural Engine (ANE) if the state tensor dimensions (specifically the width) are not a multiple of 32. The model works perfectly on CPU and GPU, but fails on ANE both during runtime and when generating a Performance Report in Xcode.
Error Message in Xcode UI:
"There was an error creating the performance report Unable to compute the prediction using ML Program. It can be an invalid input data or broken/unsupported model."
Observations:
Case A (Fails): State shape = (1, 3, 480, 270). Prediction fails on ANE.
Case B (Success): State shape = (1, 3, 480, 256). Prediction succeeds on ANE.
This suggests an internal memory alignment or tiling issue within the ANE driver when handling Stateful buffers that don't meet the 32-pixel/element alignment.
Reproduction Code (PyTorch + coremltools):
import torch.nn as nn
import coremltools as ct
import numpy as np
class RNN_Stateful(nn.Module):
def __init__(self, hidden_shape):
super(RNN_Stateful, self).__init__()
# Simple conv to update state
self.conv1 = nn.Conv2d(3 + hidden_shape[1], hidden_shape[1], kernel_size=3, padding=1)
self.conv2 = nn.Conv2d(hidden_shape[1], 3, kernel_size=3, padding=1)
self.register_buffer("hidden_state", torch.ones(hidden_shape, dtype=torch.float16))
def forward(self, imgs):
self.hidden_state = self.conv1(torch.cat((imgs, self.hidden_state), dim=1))
return self.conv2(self.hidden_state)
# h=480, w=255 causes ANE failure. w=256 works.
b, ch, h, w = 1, 3, 480, 255
model = RNN_Stateful((b, ch, h, w)).eval()
traced_model = torch.jit.trace(model, torch.randn(b, 3, h, w))
mlmodel = ct.convert(
traced_model,
inputs=[ct.TensorType(name="input_image", shape=(b, 3, h, w), dtype=np.float16)],
outputs=[ct.TensorType(name="output", dtype=np.float16)],
states=[ct.StateType(wrapped_type=ct.TensorType(shape=(b, ch, h, w), dtype=np.float16), name="hidden_state")],
minimum_deployment_target=ct.target.iOS18,
convert_to="mlprogram"
)
mlmodel.save("rnn_stateful.mlpackage")
Steps to see the error:
Open the generated .mlpackage in Xcode 16.0+.
Go to the Performance tab and run a test on a device with ANE (e.g., iPhone 15/16 or M-series Mac).
The report will fail to generate with the error mentioned above.
Environment:
OS: macOS 15.2
Xcode: 16.3
Hardware: M4
Has anyone else encountered this 32-pixel alignment requirement for StateType tensors on ANE? Is this a known hardware constraint or a bug in the Core ML runtime?
Any insights or workarounds (other than manual padding) would be appreciated.
Documentation on adapter train is lacking any details related to training on dataset with tool calling. And page about tool calling itself only explain how to use it from Swift without any internal details useful in training.
Question is how schema should looks like for including tool calling in dataset?
Topic:
Machine Learning & AI
SubTopic:
Foundation Models
With the release of the newest version of tahoe and MLX supporting RDMA. Is there a documentation link to how to utilizes the libdrma dylib as well as what functions are available? I am currently assuming it mostly follows the standard linux infiniband library but I would like the apple specific details.
Topic:
Machine Learning & AI
SubTopic:
General
I am running some experiments with WebGPU using the wgpu crate in rust. I have some Buffers already allocated in the GPU.
Is it possible to use those already existing buffers directly as inputs to a predict call in CoreML? I want to prevent gpu to cpu download time as much as possible.
Or are there any other ways to do something like this. Is this only possible using the latest Tensor object which came out with Metal 4 ?
:
Hello, I’m seeking clarification on whether Apple provides any framework or API that enables deep integration between Siri and advanced AI assistants (such as ChatGPT), including system-level functions like voice interaction, navigation, cross-platform syncing, and operational access similar to Siri’s own capabilities. If no such option exists today, I would appreciate guidance on the recommended path or approved third-party solutions for building a unified, voice-first experience across Apple’s ecosystem. Thank you for your time and insight.
I'm implementing an LLM with Metal Performance Shader Graph, but encountered a very strange behavior, occasionally, the model will report an error message as this:
LLVM ERROR: SmallVector unable to grow. Requested capacity (9223372036854775808) is larger than maximum value for size type (4294967295)
and crash, the stack backtrace screenshot is attached. Note that 5th frame is
mlir::getIntValues<long long>
and 6th frame is
llvm::SmallVectorBase<unsigned int>::grow_pod
It looks like mlir mistakenly took a 64 bit value for a 32 bit type. Unfortunately, I could not found the source code of
mlir::getIntValues, maybe it's Apple's closed source fork of llvm for MPS implementation? Anyway, any opinion or suggestion on that?
Topic:
Machine Learning & AI
SubTopic:
General
I'm using Vision framework (DetectFaceLandmarksRequest) with the same code and the same test image to detect face landmarks. On iOS 18 everything works as expected: detected face landmarks align with the face correctly.
But when I run the same code on devices with iOS 26, the landmark coordinates are outside the [0,1] range, which indicates they are out of face bounds.
Fun fact: the old VNDetectFaceLandmarksRequest API works very well without encountering this issue
How I get face landmarks:
private let faceRectangleRequest = DetectFaceRectanglesRequest(.revision3)
private var faceLandmarksRequest = DetectFaceLandmarksRequest(.revision3)
func detectFaces(in ciImage: CIImage) async throws -> FaceTrackingResult {
let faces = try await faceRectangleRequest.perform(on: ciImage)
faceLandmarksRequest.inputFaceObservations = faces
let landmarksResults = try await faceLandmarksRequest.perform(on: ciImage)
...
}
How I show face landmarks in SwiftUI View:
private func convert(
point: NormalizedPoint,
faceBoundingBox: NormalizedRect,
imageSize: CGSize
) -> CGPoint {
let point = point.toImageCoordinates(
from: faceBoundingBox,
imageSize: imageSize,
origin: .upperLeft
)
return point
}
At the same time, it works as expected and gives me the correct results:
region is FaceObservation.Landmarks2D.Region
let points: [CGPoint] = region.pointsInImageCoordinates(
imageSize,
origin: .upperLeft
)
After that, I found that the landmarks are normalized relative to the unalignedBoundingBox. However, I can’t access it in code. Still, using these values for the bounding box works correctly.
Things I've already tried:
Same image input
Tested multiple devices on iOS 26.2 -> always wrong.
Tested multiple devices on iOS 18.7.1 -> always correct.
Environment:
macOS 26.2
Xcode 26.2 (17C52)
Real devices, not simulator
Face Landmarks iOS 18
Face Landmarks iOS 26
Hi all,
I'm trying to find out if/when we can expect mxfp8/mxfp4 support on Apple Silicon. I've noticed that mlx now has casting data types, but all computation is still done in bf16. Would be great to reduce power consumption with support for these lower precision data types since edge inference is already typically done at a lower precision!
Thanks in advance.
Topic:
Machine Learning & AI
SubTopic:
Core ML
Using highly optimized Metal Shading Language (MSL) code, I pushed the MacBook Air M2 to its performance limits with the deformable_attention_universal kernel. The results demonstrate both the efficiency of the code and the exceptional power of Apple Silicon.
The total computational workload exceeded 8.455 quadrillion FLOPs, equivalent to processing 8,455 trillion operations. On average, the code sustained a throughput of 85.37 TFLOPS, showcasing the chip’s remarkable ability to handle massive workloads. Peak instantaneous performance reached approximately 673.73 TFLOPS, reflecting near-optimal utilization of the GPU cores.
Despite this intensity, the cumulative GPU runtime remained under 100 seconds, highlighting the code’s efficiency and time optimization. The fastest iteration achieved a record processing time of only 0.051 ms, demonstrating minimal bottlenecks and excellent responsiveness.
Memory management was equally impressive: peak GPU memory usage never exceeded 2 MB, reflecting efficient use of the M2’s Unified Memory. This minimizes data transfer overhead and ensures smooth performance across repeated workloads.
Overall, these results confirm that a well-optimized Metal implementation can unlock the full potential of Apple Silicon, delivering exceptional computational density, processing speed, and memory efficiency. The MacBook Air M2, often considered an energy-efficient consumer laptop, is capable of handling highly intensive workloads at performance levels typically expected from much larger GPUs. This test validates both the robustness of the Metal code and the extraordinary capabilities of the M2 chip for high-performance computing tasks.
I’m trying to follow Apple’s “WWDC24: Bring your machine learning and AI models to Apple Silicon” session to convert the Mistral-7B-Instruct-v0.2 model into a Core ML package, but I’ve run into a roadblock that I can’t seem to overcome. I’ve uploaded my full conversion script here for reference:
https://pastebin.com/T7Zchzfc
When I run the script, it progresses through tracing and MIL conversion but then fails at the backend_mlprogram stage with this error:
https://pastebin.com/fUdEzzKM
The core of the error is:
ValueError: Op "keyCache_tmp" (op_type: identity) Input x="keyCache" expects list, tensor, or scalar but got state[tensor[1,32,8,2048,128,fp16]]
I’ve registered my KV-cache buffers in a StatefulMistralWrapper subclass of nn.Module, matching the keyCache and valueCache state names in my ct.StateType definitions, but Core ML’s backend pass reports the state tensor as an invalid input. I’m using Core ML Tools 8.3.0 on Python 3.9.6, targeting iOS18, and forcing CPU conversion (MPS wasn’t available). Any pointers on how to satisfy the handle_unused_inputs pass or properly declare/cache state for GQA models in Core ML would be greatly appreciated!
Thanks in advance for your help,
Usman Khan
Topic:
Machine Learning & AI
SubTopic:
Core ML
Tags:
Metal
Metal Performance Shaders
Core ML
tensorflow-metal
I'm downloading a fine-tuned model from HuggingFace which is then cached on my Mac when the app first starts. However, I wanted to test adding a progress bar to show the download progress. To test this I need to delete the cached model. From what I've seen online this is cached at
/Users/userName/.cache/huggingface/hub
However, if I delete the files from here, using Terminal, the app still seems to be able to access the model.
Is the model cached somewhere else?
On my iPhone it seems deleting the app also deletes the cached model (app data) so that is useful.
Hello Team,
I'm currently working on a proof of concept using Apple's Foundation Model for a RAG-based chat system on my MacBook Pro with the M1 Max chip.
Environment details:
macOS: 26.0 Beta
Xcode: 26.0 beta 2 (17A5241o)
Target platform: iPad (as the iPhone simulator does not support Foundation models)
While testing, even with very small input prompts to the LLM, I intermittently encounter the following error:
InferenceError::inference-Failed::Failed to run inference: Context length of 4096 was exceeded during singleExtend.
Has anyone else experienced this issue? Are there known limitations or workarounds for context length handling in this setup?
Any insights would be appreciated.
Thank you!
Topic:
Machine Learning & AI
SubTopic:
Foundation Models
I watched this year WWDC25 "Read Documents using the Vision framework". At the end of video there is mention of new DetectHandPoseRequest model for hand pose detection in Vision API.
I looked Apple documentation and I don't see new revision. Moreover probably typo in video because there is only DetectHumanPoseRequst (swift based) and
VNDetectHumanHandPoseRequest (obj-c based) (notice lack of Human prefix in WWDC video)
First one have revision only added in iOS 18+:
https://developer.apple.com/documentation/vision/detecthumanhandposerequest/revision-swift.enum/revision1
Second one have revision only added in iOS14+:
https://developer.apple.com/documentation/vision/vndetecthumanhandposerequestrevision1
I don't see any new revision targeting iOS26+
I can’t seem to find a way to include an image when prompting the new on-device model in Xcode, even though Apple explicitly states that the model was trained and tested with image data (https://machinelearning.apple.com/research/apple-foundation-models-2025-updates).
Has anyone managed to get this working, or are VLM-style capabilities simply not exposed yet?
Topic:
Machine Learning & AI
SubTopic:
Foundation Models
I am using gemini2.5-flash with SwiftUI. How can I receive a response in JSON?
Topic:
Machine Learning & AI
SubTopic:
General
Lookin for J - is this a safe place for discussing full apps ive built but not submitted or shared , I have maybe over 100 but had been unaware any assistance was provided..
is there a formal process to take to submit an app fro review to improve OS, other than during App Store review.
Topic:
Machine Learning & AI
SubTopic:
Apple Intelligence
Tags:
Design
Developer Tools
iCloud Drive
Xcode
Hi everyone,
I'm trying to use VNDetectTextRectanglesRequest to detect text rectangles in an image. Here's my current code:
guard let cgImage = image.cgImage(forProposedRect: nil, context: nil, hints: nil) else {
return
}
let textDetectionRequest = VNDetectTextRectanglesRequest { request, error in
if let error = error {
print("Text detection error: \(error)")
return
}
guard let observations = request.results as? [VNTextObservation] else {
print("No text rectangles detected.")
return
}
print("Detected \(observations.count) text rectangles.")
for observation in observations {
print(observation.boundingBox)
}
}
textDetectionRequest.revision = VNDetectTextRectanglesRequestRevision1
textDetectionRequest.reportCharacterBoxes = true
let handler = VNImageRequestHandler(cgImage: cgImage, orientation: .up, options: [:])
do {
try handler.perform([textDetectionRequest])
} catch {
print("Vision request error: \(error)")
}
The request completes without error, but no text rectangles are detected — the observations array is empty (count = 0). Here's a sample image I'm testing with:
I expected VNTextObservation results, but I'm not getting any. Is there something I'm missing in how this API works? Or could it be a limitation of this request or revision?
Thanks for any help!