CODEWITHSUNDEEP
arraysswiftcoreml
Aneesh Prabu
Aneesh Prabu

Reputation: 175

Convert [MLMultiArray] to Float?

I have an MLMultiArray which is a result of an ML Model. I need to convert it to Float so that I can further store it in Realm.

Below is an example of one of the MLMultiArray. The result from the ML Model contains 120 of the same vectors so its an array of MLMultiArrays i.e Array of Float32 1 x 128 matrices. 

Float32 1 x 128 matrix
[4.476562,1.179688,0.07141113,6.976562,-0.2858887,-7.378906,0.6445312,3.695312,1.399414,2.486328,-3.988281,-0.2636719,1.000977,-4.480469,-7.832031,1.59082,0.8515625,-1.296875,-1.435547,7.839844,5.851562,0.3701172,-2.492188,7.273438,2.404297,-3.3125,-5.699219,-0.6816406,0.2807617,-3.882812,-3.982422,5.339844,4.125,-3.871094,0.6225586,1.712891,-10.02344,0.7119141,4.472656,3.566406,-0.559082,-1.049805,-4.679688,10.07812,-1.459961,4.707031,-6.078125,1.675781,-0.6259766,2.519531,3.472656,-3.400391,-6.714844,-4.933594,-1.733398,1.095703,-6.15625,9.234375,3.693359,-9.492188,0.8637695,0.8203125,-2.814453,-4.4375,-1.092773,3.332031,0.1623535,3.583984,-11.25781,-0.9941406,-0.3491211,1.464844,-1.579102,4.558594,2.703125,4.601562,5.914062,-2.402344,-5.46875,-0.355957,11.39062,2.070312,-7.289062,-0.4470215,-0.1595459,9.148438,1.833008,-2.097656,-3.9375,6.699219,-4.347656,-6.835938,-1.179688,3.910156,-13.07812,-1.947266,-0.9238281,-0.949707,-4.398438,2.363281,4.421875,4.632812,2.607422,8.773438,0.9106445,9.21875,-14.0625,-1.301758,-4.875,0.6054688,6.496094,-2.021484,3.898438,-4.644531,0.9853516,7.253906,3.066406,-1.051758,-8.09375,-6.527344,3.890625,5.175781,0.3701172,-0.5683594,-1.341797,0.1497803,4.074219,0.5932617]

Is there any way I can convert an array of MLMultiArray to Float32?

Any help would be appreciated <3

Upvotes: 4

Views: 4631

Answers (3)

holsety
holsety

Reputation: 323

I'm using this way, and subscript to access the element and it works fine for me.

const float *array = (float*)matrix.dataPointer

Upvotes: 0

soufianeios
soufianeios

Reputation: 456

This is old question but this can help someone: To convert from an MLMultiArray To An Array of primitive, You can use this function you will need just to change the output type

func convertToArray(from mlMultiArray: MLMultiArray) -> [Double] {
    
    // Init our output array
    var array: [Double] = []
    
    // Get length
    let length = mlMultiArray.count
    
    // Set content of multi array to our out put array
    for i in 0...length - 1 {
        array.append(Double(truncating: mlMultiArray[[0,NSNumber(value: i)]]))
    }
    
    return array
}

To convert from an Array to MLMultiArray Use this, you may need to change the shape accordingly

func convertToMLMultiArray(from array: [Double]) -> MLMultiArray {
    let length = NSNumber(value: array.count)
    
    // Define shape of array
    guard let mlMultiArray = try? MLMultiArray(shape:[1, length], dataType:MLMultiArrayDataType.double) else {
        fatalError("Unexpected runtime error. MLMultiArray")
    }
    
    // Insert elements
    for (index, element) in array.enumerated() {
        mlMultiArray[index] = NSNumber(floatLiteral: element)
    }
    
    return mlMultiArray
}

Upvotes: 6

Matthijs Hollemans
Matthijs Hollemans

Reputation: 7892

You can first convert the MLMultiArray to an UnsafeBufferPointer and then to a regular Array.

import CoreML

var a: [Float] = [ 1, 2, 3 ]
var m = try! MLMultiArray(a)

if let b = try? UnsafeBufferPointer<Float>(m) {
  let c = Array(b)
  print(c)
}

Upvotes: 6

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