在Swift中使用加速框架的cblas_dgemm問題

Question

我想在Swift中乘以兩個矩陣。我在這個主題中發現了一個很好的回覆：matrix multiplication in swift using Accelerate framework 32 bit vs 64 bit，其中我被告知使用cblas_dgemm來乘以兩個矩陣。 這裏是我的代碼：

import SpriteKit 
import Accelerate 


class GetMatrix { 
var cols:Int, rows:Int 
var matrix:[Double] 


init(cols:Int, rows:Int) { 
    self.cols = cols 
    self.rows = rows 
    matrix = Array(count:cols*rows, repeatedValue:0.0) 
} 

subscript(col:Int, row:Int) -> Double { 
    get { 
     return matrix[cols * row + col] 
    } 
    set { 
     matrix[cols*row+col] = newValue 
    } 
} 

func colCount() -> Int { 
    return self.cols 
} 

func rowCount() -> Int { 
    return self.rows 
} 
} 
class GameScene: SKScene { 


var firstMatrix = GetMatrix(cols: 18, rows: 18) 
var secondMatrix = GetMatrix(cols: 18, rows: 18) 
var answerMatrix = GetMatrix(cols: 18, rows: 18) 


override func didMoveToView(view: SKView) { 

    for c in 0...17 { 
     for r in 0...17 { 
      firstMatrix[r,c] = 2.0 
     } 
    } 
    for c in 0...17 { 
     for r in 0...17 { 
      secondMatrix[r,c] = 1.0 
     } 
    } 
    for c in 0...17 { 
     for r in 0...17 { 
      answerMatrix[r,c] = 0.0 
     } 
    } 


    cblas_dgemm(CblasRowMajor, CblasNoTrans, CblasNoTrans, 18, 18, 18, 1.0, firstMatrix, 18, secondMatrix, 18, 0.0, answerMatrix, 18) // Error in this line 



} 


} 

該代碼不會構建。與cblas_dgemm的行有問題。它說：「GetMatrix」是無法轉換爲‘UnsafePointer’請幫幫忙，我該如何解決這個問題？

Answer 1

var firstMatrix = GetMatrix(cols: 18, rows: 18) 
var secondMatrix = GetMatrix(cols: 18, rows: 18) 
var answerMatrix = GetMatrix(cols: 18, rows: 18) 
. 
. 
. 
cblas_dgemm(CblasRowMajor, CblasNoTrans, CblasNoTrans, 18, 18, 18, 1.0, firstMatrix, 18, secondMatrix, 18, 0.0, answerMatrix, 18) 

你的代碼將類GetMatrix到cblas_dgemm，你將不得不通過參考實際的矩陣。東西像

cblas_dgemm(CblasRowMajor, CblasNoTrans, CblasNoTrans, 18, 18, 18, 1.0, &firstMatrix.matrix, 18, &secondMatrix.matrix, 18, 0.0, &answerMatrix.matrix, 18) 

（前提是其他參數是否正確）