so, my app needs to find the dominant palette and the position in the image of the k-most dominant colors. I followed the very useful sample project from the vImage documentation
https://developer.apple.com/documentation/accelerate/bnns/calculating_the_dominant_colors_in_an_image
and the algorithm works fine although I can't wrap my head around how should I go on about and linking said colors with a point in the image. Since the algorithm works by filling storages first, I tried also filling an array of CGPoints called LocationStorage and working with that
//filling the array
for i in 0...width {
for j in 0...height {
locationStorage.append(
CGPoint(x: i, y: j))
}
.
.
.
//working with the array
let randomIndex = Int.random(in: 0 ..< width * height)
centroids.append(Centroid(red: redStorage[randomIndex],
green: greenStorage[randomIndex],
blue: blueStorage[randomIndex],
position: locationStorage[randomIndex]))
}
struct Centroid {
/// The red channel value.
var red: Float
/// The green channel value.
var green: Float
/// The blue channel value.
var blue: Float
/// The number of pixels assigned to this cluster center.
var pixelCount: Int = 0
var position: CGPoint = CGPointZero
init(red: Float, green: Float, blue: Float, position: CGPoint) {
self.red = red
self.green = green
self.blue = blue
self.position = position
}
}
although it's not accurate.
I also tried force trying every pixel in the image to get as close to each color but I think it's too slow.
What do you think my approach should be?
Let me know if you need additional info
Please be kind I'm learning Swift.
Accelerate
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I'm using M1pro and have successfully installed Numpy with Accelerate following, and it really speedup my programs. I also ran np.test() to check the correctness and every test passed.
However, I can't install Scipy with Accelerate, since the official document said Accelerate has a LAPACK of too old version. I can't even find a scipy that can pass scipy.test(). I tried the codes below:
conda install numpy 'libblas=*=*accelerate'
conda install scipy
np.test() as fails, sp.test() can't even finish
conda install numpy 'libblas=*=*openblas'
conda install scipy
Both np.test() and sp.test() can finish, but with many failures. I believe the bugs are due to Conda.
pip install --no-binary :all: --no-use-pep517 numpy
pip install scipy
np.test() has no failure and went fast, sp.test() uses OpenBLAS and has 3 failures. This is the best version I have found.
So my question is: can we find a reliable version of scipy on M1? Considering the popularity of scipy, I think it's not a high-living expectation.
And a question for Apple: is there really a plan to upgrade the LAPACK in Accelerate?