C＃调用英特尔MKL cblas_dgemm_batch

Question

我可以从C＃调用英特尔MKL cblas_dgem，请参阅下面的代码：

[DllImport("custom_mkl", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true, SetLastError = false)] 
internal static extern void cblas_dgemm(
    int Order, int TransA, int TransB, MKL_INT M, MKL_INT N, MKL_INT K, 
    double alpha, [In] double[,] A, MKL_INT lda, [In] double[,] B, MKL_INT ldb, 
    double beta, [In, Out] double[,] C, MKL_INT ldc); 

和

void cblas_dgemm (const CBLAS_LAYOUT Layout, const CBLAS_TRANSPOSE transa, const CBLAS_TRANSPOSE transb, const MKL_INT m, const MKL_INT n, const MKL_INT k, const double alpha, const double *a, const MKL_INT lda, const double *b, const MKL_INT ldb, const double beta, double *c, const MKL_INT ldc); 

但我不能够调用cblas_dgemm_batch从C＃，看下面的代码：

[DllImport("custom_mkl", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true, SetLastError = false)] // not working 
internal static extern void cblas_dgemm_batch(
    int Layout, [In] int[] transa_array, [In] int[] transb_array, [In] MKL_INT[] m_array, [In] MKL_INT[] n_array, [In] MKL_INT[] k_array, 
    [In] double[] alpha_array, [In] double[][,] a_array, [In] MKL_INT[] lda_array, [In] double[][,] b_array, [In] MKL_INT[] ldb_array, 
    [In] double[] beta_array, [In, Out] double[][,] c_array, [In] MKL_INT[] ldc_array, MKL_INT group_count, [In] MKL_INT[] group_size); 

和

void cblas_dgemm_batch (const CBLAS_LAYOUT Layout, const CBLAS_TRANSPOSE* transa_array, const CBLAS_TRANSPOSE* transb_array, const MKL_INT* m_array, const MKL_INT* n_array, const MKL_INT* k_array, const double* alpha_array, const double **a_array, const MKL_INT* lda_array, const double **b_array, const MKL_INT* ldb_array, const double* beta_array, double **c_array, const MKL_INT* ldc_array, const MKL_INT group_count, const MKL_INT* group_size); 

我收到以下错误信息：

• System.Runtime.InteropServices.MarshalDirectiveException
• 不能元帅参数＃8“：对于嵌套数组没有封送处理支持。

我可以理解，问题是嵌套的数组参数。该参数应该是指向数组的指针数组。但是，我怎样才能从C＃调用cblas_dgemm_batch？

Answer 1

使用以下custom marshaler for the jagged arrays是解决方案：

class JaggedArrayMarshaler : ICustomMarshaler 
{ 
    static ICustomMarshaler GetInstance(string cookie) 
    { 
     return new JaggedArrayMarshaler(); 
    } 
    GCHandle[] handles; 
    GCHandle buffer; 
    Array[] array; 
    public void CleanUpManagedData(object ManagedObj) 
    { 
    } 
    public void CleanUpNativeData(IntPtr pNativeData) 
    { 
     buffer.Free(); 
     foreach (GCHandle handle in handles) handle.Free(); 
    } 
    public int GetNativeDataSize() 
    { 
     return IntPtr.Size; 
    } 
    public IntPtr MarshalManagedToNative(object ManagedObj) 
    { 
     array = (Array[])ManagedObj; 
     handles = new GCHandle[array.Length]; 
     for (int i = 0; i < array.Length; i++) 
      handles[i] = GCHandle.Alloc(array[i], GCHandleType.Pinned); 
     IntPtr[] pointers = new IntPtr[handles.Length]; 
     for (int i = 0; i < handles.Length; i++) 
      pointers[i] = handles[i].AddrOfPinnedObject(); 
     buffer = GCHandle.Alloc(pointers, GCHandleType.Pinned); 
     return buffer.AddrOfPinnedObject(); 
    } 
    public object MarshalNativeToManaged(IntPtr pNativeData) 
    { 
     return array; 
    } 
} 

并且使用上述封送：

[DllImport("custom_mkl", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true, SetLastError = false)] 
internal static extern void cblas_dgemm_batch(
    int Layout, [In] int[] transa_array, [In] int[] transb_array, [In] MKL_INT[] m_array, [In] MKL_INT[] n_array, [In] MKL_INT[] k_array, 
    [In] double[] alpha_array, 
    [MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(JaggedArrayMarshaler))][In] double[][,] a_array, [In] MKL_INT[] lda_array, 
    [MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(JaggedArrayMarshaler))][In] double[][,] b_array, [In] MKL_INT[] ldb_array, 
    [In] double[] beta_array, 
    [MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(JaggedArrayMarshaler))][In, Out] double[][,] c_array, 
    [In] MKL_INT[] ldc_array, MKL_INT group_count, [In] MKL_INT[] group_size); 

我使用以下代码来测试它：

public static double[][,] Dot(double[][,] a, double[][,] b) 
{ 
    int n0 = a.Length; 
    if (b.Length != n0) throw new System.Exception("Group size must be the same"); 
    int Order = 101; // row-major arrays 
    int[] TransA = new int[n0]; 
    int[] TransB = new int[n0]; 
    MKL_INT[] M = new MKL_INT[n0]; 
    MKL_INT[] N = new MKL_INT[n0]; 
    MKL_INT[] K = new MKL_INT[n0]; 
    double[] alpha = new double[n0]; 
    double[] beta = new double[n0]; 
    double[][,] c = new double[n0][,]; 
    MKL_INT GroupCount = n0; 
    MKL_INT[] GroupSize = new MKL_INT[n0]; 
    for (int i0 = 0; i0 < n0; i0++) 
    { 
     int n1 = a[i0].GetLength(0); 
     int n2 = a[i0].GetLength(1); 
     int n3 = b[i0].GetLength(0); 
     int n4 = b[i0].GetLength(1); 
     if (n2 != n3) throw new System.Exception("Inner matrix dimensions must agree"); 
     TransA[i0] = 111; // trans='N' 
     TransB[i0] = 111; // trans='N' 
     M[i0] = n1; N[i0] = n4; K[i0] = n2; 
     alpha[i0] = 1; beta[i0] = 0; 
     c[i0] = new double[n1, n4]; 
     GroupSize[i0] = 1; 
    } 
    MKL_INT[] lda = K; 
    MKL_INT[] ldb = N; 
    MKL_INT[] ldc = N; 
    _mkl.cblas_dgemm_batch(Order, TransA, TransB, M, N, K, alpha, a, lda, b, ldb, beta, c, ldc, GroupCount, GroupSize); 
    return c; 
} 

和

double[,] A0 = new double[,] { { 1, 2 }, { 3, 4 } }; 
double[,] A1 = new double[,] { { 5, 6 }, { 7, 8 } }; 
double[,] B0 = new double[,] { { 9, 10 }, { 11, 12 } }; 
double[,] B1 = new double[,] { { 13, 14 }, { 15, 16 } }; 
double[][,] A = new double[][,] { A0, A1 }; 
double[][,] B = new double[][,] { B0, B1 }; 
double[][,] C = MKL.Dot(A, B); 

当我运行它的代码的作品。我可以在调试器中看到，在调用cblas_dgemm_batch之前，方法MarshalManagedToNative被调用3次（如预期的那样）。