Using Eigen from Swift (via C)

Talk given iOSDC Japan 2021.
https://fortee.jp/iosdc-japan-2021/proposal/df47003d-68c2-45a1-ba1d-f8d5a400f4cd

Transcript

1. Using Eigen from Swift (via C)
   Using Eigen from Swift (via C)
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2. Using Eigen from Swift (via C)
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3. Using Eigen from Swift (via C)
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4. Using Eigen from Swift (via C)
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   let a = EigenIntMatrix( ... )
   
   
   let b = EigenDoubleMatrix( ... )
   
   
   let c = EigenRationalMatrix( ... )
   
   
   🙅
   let a = EigenMatrix( ... )
   
   
   let b = EigenMatrix( ... )
   
   
   let c = EigenMatrix( ... )
   
   
   🙆
   

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5. Using Eigen from Swift (via C)
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   4XJGU $ $
   EigenMatrix
   EigenMatrix
   Eigen::Matrix
   Eigen::Matrix
   EigenMatrix Eigen::Matrix
   

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6. Using Eigen from Swift (via C)
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   protocol Scalar {
   
   
   static func + (a: Self, b: Self) -> Self
   
   
   static func - (a: Self, b: Self) -> Self
   
   
   static func * (a: Self, b: Self) -> Self
   
   
   …
   
   
   }
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   extension Int: Scalar {}
   
   
   extension Double: Scalar {}
   
   
   struct Rational: Scalar {
   
   
   …
   
   
   }
   
   
   4XJGU
   

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7. Using Eigen from Swift (via C)
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   typealias EigenMatrixPointer = UnsafeMutableRawPointer
   
   
   typealias EigenMatrixOperation =
   
   
   (EigenMatrixPointer,
   
   
   EigenMatrixPointer,
   
   
   EigenMatrixPointer) -> Void
   
   
   protocol EigenCompatibleScalar: Scalar {
   
   
   static var eigen_init: (Int, Int) -> EigenMatrixPointer { get }
   
   
   static var eigen_add: EigenMatrixOperation { get }
   
   
   static var eigen_minus: EigenMatrixOperation { get }
   
   
   static var eigen_mul: EigenMatrixOperation { get }
   
   
   …
   
   
   }
   4XJGU
   

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8. Using Eigen from Swift (via C)
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   struct EigenMatrix {
   
   
   private var ptr: EigenMatrixPointer
   
   
   init(size: MatrixSize) {
   
   
   let ptr = R.eigen_init(size.rows, size.cols)
   
   
   self.ptr = ptr
   
   
   }
   
   
   
   
   static func + (a: Self, b: Self) -> Self {
   
   
   let c = Self(size: a.size)
   
   
   R.eigen_add(a.ptr, b.ptr, c.ptr)
   
   
   return c
   
   
   }
   
   
   …
   
   
   }
   4XJGU
   

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9. Using Eigen from Swift (via C)
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   extension Int: EigenCompatibleScalar {
   
   
   static var eigen_init = eigen_int_init
   
   
   static var eigen_add = eigen_int_add
   
   
   static var eigen_minus = eigen_int_minus
   
   
   static var eigen_mul = eigen_int_mul
   
   
   …
   
   
   }
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   void *eigen_int_init(int rows, int cols);
   
   
   void eigen_int_add (void *a, void *b, void *c);
   
   
   void eigen_int_minus(void *a, void *b, void *c);
   
   
   void eigen_int_mul (void *a, void *b, void *c);
   $
   EigenMatrixPointer
   EigenMatrixOperation
   

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10. Using Eigen from Swift (via C)
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    4XJGU$
    
    extension Double: EigenCompatibleScalar {
    
    
    static var eigen_init = eigen_dbl_init
    
    
    static var eigen_add = eigen_dbl_add
    
    
    static var eigen_minus = eigen_dbl_minus
    
    
    static var eigen_mul = eigen_dbl_mul
    
    
    …
    
    
    }
    4XJGU
    void *eigen_dbl_init(int rows, int cols);
    
    
    void eigen_dbl_add (void *a, void *b, void *c);
    
    
    void eigen_dbl_minus(void *a, void *b, void *c);
    
    
    void eigen_dbl_mul (void *a, void *b, void *c);
    $
    

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11. Using Eigen from Swift (via C)
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    $$
    
    #import
    
    
    using IntMatrix = Eigen::Matrix;
    
    
    void *eigen_int_init(int_t rows, int_t cols) {
    
    
    IntMatrix *A = new IntMatrix(rows, cols);
    
    
    A->setZero();
    
    
    return static_cast(A);
    
    
    }
    
    
    

    void eigen_int_add(void *a, void *b, void *c) {
    
    
    IntMatrix *A = static_cast(a);
    
    
    IntMatrix *B = static_cast(b);
    
    
    IntMatrix *C = static_cast(c);
    
    
    *C = *A + *B;
    
    
    }
    
    
    $
    

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12. Using Eigen from Swift (via C)
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    $$
    
    #import
    
    
    using DoubleMatrix = Eigen::Matrix;
    
    
    void *eigen_dbl_init(int_t rows, int_t cols) {
    
    
    DoubleMatrix *A = new DoubleMatrix(rows, cols);
    
    
    A->setZero();
    
    
    return static_cast(A);
    
    
    }
    
    
    

    void eigen_dbl_add(void *a, void *b, void *c) {
    
    
    DoubleMatrix *A = static_cast(a);
    
    
    DoubleMatrix *B = static_cast(b);
    
    
    DoubleMatrix *C = static_cast(c);
    
    
    *C = *A + *B;
    
    
    }
    
    
    $
    

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13. Using Eigen from Swift (via C)
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    *UXPSLT
    
    let a: EigenMatrix2x2 = [1, 2, 3, 4]
    
    
    let b: EigenMatrix2x2 = [5, 6, 7, 8]
    
    
    print(a + b)
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    [6, 8; 10, 12]
    DPOTPMF
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14. Using Eigen from Swift (via C)
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