I have a doubt regarding slicing the sparse matrix on GPU.I don’t know why does the result matrix start assigning values from the second row.This is an unexpected result for me.How can i fix the error?

```
using CUDA
using CUDA.CUSPARSE
using SparseArrays
using Printf
a = [1,2,3]
b = [1,2,3]
n = 10 # size of the matrix
density = 0.7 # density of the non-zero elements
sparse_matrix = sprand(n, n, density)
na = length(a)
nb = length(b)
a_gpu = CUDA.CuArray(a)
b_gpu = CUDA.CuArray(b)
result = CUDA.zeros(Float32, na, nb)
# Convert to CuSparseMatrixCSC
sparse_matrix_gpu = CUDA.CUSPARSE.CuSparseMatrixCSC(sparse_matrix)
#The col_indices
col=sparse_matrix_gpu.colPtr
#the row_indices
row=sparse_matrix_gpu.rowVal
#the values
val=sparse_matrix_gpu.nzVal
function kernel_index!(result,row_indices,col_ptrs,val,a,b,na,nb)
i=threadIdx().x+(blockIdx().x-1)*blockDim().x+1
if(i<=na)
for j in 1:nb
row=a[i]-1
col=b[j]
value=0.0
for k in col_ptrs[col]:(col_ptrs[col+1]-1)
if row_indices[k]==row
value=val[k]
break
end
end
result[i,j]=value
end
end
return
end
threads_per_block = 256
blocks_per_grid = ceil(Int, na / threads_per_block)
@cuda threads=threads_per_block blocks=blocks_per_grid kernel_index!(result, row, col, val, a_gpu, b_gpu, na, nb)
```

The result matrix is

```
julia> result
3×3 CuArray{Float32, 2, CUDA.DeviceMemory}:
0.0 0.0 0.0
0.0 0.248917 0.263072
0.128449 0.0 0.620226
```

It only saves sparse_matrix_gpu [1:2,1:3] and starts assigning values from the second row of the result matrix