Hello dear sirs,

I am student from Russia, working on my course work (Monte-Carlo method for solving sparse SLAE on GPU) and i can’t find out why my kernell crashes, when i use curand_uniform() function from library CURAND. May be someone can help me to understand my mistakes, I am in deep depression because I can’t understand what i am doing wrong in whole week. Here i post kernel code and host code. Deeply sorry for my English!

Kernel launche code:

devP is a pointer to 1 dimensional massive of floats; devV, devColInd, devOffsets is a pointers to 1 dimensional massive of ints. This massives (devP, devColInd, devOffsets) discribes sparse matrix in compressed raw format, devV is additional data to this matrix.

```
testKernel<<<1, 1>>>(devP, devV, devColInd, devOffsets, B, time(NULL), stohNum, devRes);
cudaError_t error = cudaGetLastError();
if(error != cudaSuccess)
{
printf("Cuda error: %s\n", cudaGetErrorString(error));
printf("Press enter to quit with -1 code\n");
getchar();
exit(-1);
}
```

When I check kernel execution with cuda error i get “unknown error”

Kernel definition code:

```
__global__ void testKernel(float *p, int *v, int *colInd, int *offsets, float *B, unsigned long seed, int numStoh, float *res)
{
int gid = threadIdx.x;
int counter = 0;
float xx = 0.0, x = 0.0;
float rNum = 0.0;
float accSum = 0.0;
int vv = 1;
int curEq = 0;// kp = 0;
int exit = 0;
int isFound = 0;
int root = 1;
curandState localState;
curand_init(seed, gid, 0, &localState);
while(counter < numStoh)
{
curEq = root;
xx = B[root];
vv = 1;
exit = 0;
while(!exit)//create Markov's chain
{
//kp = k; //save previos state
rNum = curand_uniform(&localState);//((float)rand()/((float)RAND_MAX));
accSum = 0.0;
isFound = 0;
for(int j = 0; j < offsets[curEq+1] - offsets[curEq]; j++)
{
if(((rNum > accSum) && (rNum < accSum + p[offsets[curEq] + j])) || (rNum == accSum))
{
vv = vv*v[offsets[curEq] + j];
curEq = colInd[offsets[curEq] +j];
xx = xx + vv*B[curEq];
isFound = 1;
break;
}
accSum += p[offsets[curEq] + j];
}
if(isFound != 1)//particle reach the border
{
exit = 1;
}
}
x += xx;
counter++;
}
res[0] = x;
}
```

if I for example cooment line with curand_uniform() and replace it with rNum = 0.99 then kernel will finish execution with ok status, may there is a problem with massives but i checked it thousands times. So I have not ideas whats wrong…