试图遵守此代码，但失败并显示错误。使用此代码比较2d数组的元素

Question

这是比较2d数组元素的cuda代码。但是在编译时会显示错误。我使用的是pycuda，我发布了我想实现的所有代码。

import pycuda.driver as cuda
import pycuda.autoinit
from pycuda.compiler import SourceModule
import numpy
c = numpy.empty((2,2), dtype = object)
d = numpy.empty((2,2), dtype = object)
for i in range(0,2):
  for j in range(0,2):
    c[i][j]= input("Value for c")
    d[i][j]= input("Value for d")
c_gpu = cuda.mem_alloc(c.nbytes)
d_gpu = cuda.mem_alloc(d.nbytes)
cuda.memcpy_htod(c_gpu, c)
cuda.memcpy_htod(d_gpu, d)
module1 = SourceModule ("""
__device__ int mystrcmp(const char *str_a, const char *str_b, unsigned len = 256){
  int match = 1;
  unsigned i = 0;
  while ((i < len) && (match == 1) ){
    if (str_a[i] == str_b[i])
      i= i+1;
    else
      match = 0;
    }
  return match;
  }
__device__ void mystrasgn(const char *str_a, const char *str_b, unsigned len = 256){
  unsigned i = 0;
  while (str_b[i]!= '\0' ){
    str_a[i] = str_b[i])
      i= i+1;
    }
    str_a[i]='\0';
  }
__global__ void com(char **c, char **d)
{
  int idx = threadIdx.x + threadIdx.y*blockDim.x;
  if(mystrcmp(c[idx], d[idx]))
    mystrasgn(c[idx], c[idx]);
  else
    mystrasgn(c[idx], d[idx]);
}
""")
__device__ int mystrcmp(const char *str_a, const char *str_b, unsigned len = 256){
  int match = 1;
  unsigned i = 0;
  while ((i < len) && (match == 1) ){
    if (str_a[i] == str_b[i])
      i= i+1;
    else
      match = 0;
    }
  return match;
  }
__device__ void mystrasgn(const char *str_a, const char *str_b, unsigned len = 256){
  unsigned i = 0;
  while (str_b[i]!= '\0' ){
    str_a[i] = str_b[i])
      i= i+1;
    }
    str_a[i]='\0';
  }
__global__ void com(char **c, char **d)
{
  int idx = threadIdx.x + threadIdx.y*blockDim.x;
  if(mystrcmp(c[idx], d[idx]))
    mystrasgn(c[idx], c[idx]);
  else
    mystrasgn(c[idx], d[idx]);
}
module1 = SourceModule ("""
__device__ int mystrcmp(const char *str_a, const char *str_b, unsigned len = 256){
  int match = 1;
  unsigned i = 0;
  while ((i < len) && (match == 1) ){
    if (str_a[i] == str_b[i])
      i= i+1;
    else
      match = 0;
    }
  return match;
  }
__device__ void mystrasgn(const char *str_a, const char *str_b, unsigned len = 256){
  unsigned i = 0;
  while (str_b[i]!= '\0' ){
    str_a[i] = str_b[i])
      i= i+1;
    }
    str_a[i]='\0';
  }
__global__ void com(char **c, char **d)
{
  int idx = threadIdx.x + threadIdx.y*blockDim.x;
  if(mystrcmp(c[idx], d[idx]))
    mystrasgn(c[idx], c[idx]);
  else
    mystrasgn(c[idx], d[idx]);
}
""")
fy = module1.get_function("com")
fy(c_gpu, d_gpu, block=(2,2,1))
x = numpy.empty_like(c)
cuda.memcpy_dtoh(x, c_gpu)
print(x)

我写了2个函数，一个比较两个2d数组的元素，另一个比较数组的元素。但是在编译时我收到如下错误：