我正在尝试声明一个矩阵乘法的变量，如下所示：
__shared__ float As[BLOCK_SIZE][BLOCK_SIZE];
我正在尝试让用户输入矩阵的大小以进行计算，但这意味着需要更改BLOCK_SIZE。我已经更改了它，但是我遇到了编译器错误：
error: constant value is not known
我已经研究过了，它类似于这个thread。所以我尝试了：
__shared__ int buf [];
但是我得到：
error: incomplete type is not allowed
谢谢，丹
更新代码（基本上遵循this guide和CUDA指南的开始）：
块大小是通过询问矩阵大小的用户传递的。他们输入x和y。块大小仅为x，现在必须接受与x和y相同的大小。
__global__ void matrixMul( float* C, float* A, float* B, int wA, int wB,size_t block_size)
{
// Block index
int bx = blockIdx.x;
int by = blockIdx.y;
// Thread index
int tx = threadIdx.x;
int ty = threadIdx.y;
// Index of the first sub-matrix of A processed
// by the block
int aBegin = wA * block_size * by;
// Index of the last sub-matrix of A processed
// by the block
int aEnd = aBegin + wA - 1;
// Step size used to iterate through the
// sub-matrices of A
int aStep = block_size;
// Index of the first sub-matrix of B processed
// by the block
int bBegin = block_size * bx;
// Step size used to iterate through the
// sub-matrices of B
int bStep = block_size * wB;
float Csub=0;
// Loop over all the sub-matrices of A and B
// required to compute the block sub-matrix
for (int a = aBegin, b = bBegin; a <= aEnd; a += aStep, b += bStep)
{
// Declaration of the shared memory array As
// used to store the sub-matrix of A
extern __shared__ float As[];
// Declaration of the shared memory array Bs
// used to store the sub-matrix of B
extern __shared__ float Bs[];
extern __shared__ float smem[];
// Load the matrices from global memory
// to shared memory; each thread loads
// one element of each matrix
smem[ty*block_size+tx] = A[a + wA * ty + tx];
//cuPrintf("\n\nWhat are the memory locations?\n");
//cuPrintf("The shared memory(A) is: %.2f\n",smem[ty*block_size+tx]);
smem[block_size*block_size+ty*block_size+tx] = B[b + wB * ty + tx];
//cuPrintf("The shared memory(B) is: %.2f\n",smem[block_size*block_size+ty*block_size+tx]);
// Synchronize to make sure the matrices
// are loaded
__syncthreads();
// Multiply the two matrices together;
// each thread computes one element
// of the block sub-matrix
for (int k = 0; k < block_size; ++k)
{
Csub += smem[ty*block_size+k] * smem[block_size*block_size+k*block_size+tx] ;
//cuPrintf("Csub is currently: %.2f\n",Csub);
}
//cuPrintf("\n\n\n");
// Synchronize to make sure that the preceding
// computation is done before loading two new
// sub-matrices of A and B in the next iteration
//cuPrintf("the results are csub: %.2f\n",Csub);
__syncthreads();
}
// Write the block sub-matrix to device memory;
// each thread writes one element
int c = wB * block_size * by + block_size * bx;
C[c + wB * ty + tx] = Csub;
}