I am getting much more averaged computation time by using sparse matrices structure. Is there something wrong on my code? I used a quick test script to test multiplication of both data structure.

```
using SparseArrays, Statistics
n=1000
N=1000
T = 10
t1_hist = Array{Float64}(undef, 1, T)
t2_hist = Array{Float64}(undef, 1, T)
for i in 1:T
fmatrix_1 = [rand(n,n) zeros(n,N); zeros(N,n) zeros(N,N)]
fmatrix_2 = [rand(n,n) zeros(n,N); zeros(N,n) zeros(N,N)]
spmatrix_1 = sparse([rand(n,n) spzeros(n,N); spzeros(N,n) spzeros(N,N)])
spmatrix_2 = sparse([rand(n,n) spzeros(n,N); spzeros(N,n) spzeros(N,N)])
t1_hist[i] = @elapsed fmatrix_1 * fmatrix_2;
t2_hist[i] = @elapsed spmatrix_1 * spmatrix_2;
end
println(" Full Matrix Multiplication Avg. Elapsed Time = ", mean(t1_hist) )
println("Sparse Matrix Multiplication Avg. Elapsed Time = ", mean(t2_hist) )
```