
Perform matrix multiplication of two lower triangular matrices:
$$
C = A \cdot B
$$

Where A and B are lower triangular matrices.

The result C will also be a lower triangular matrix.

## Input
- Lower triangular matrix $A$ of size $N \times N$
- Lower triangular matrix $B$ of size $N \times N$

## Output
- Lower triangular matrix $C$ of size $N \times N$

## Notes:
- All matrices $\text{A}$, $\text{B}$, and $\text{C}$ are stored in row-major order.
- A matrix $L$ is lower triangular if $L_{ij} = 0$ for all $i < j$.
- This problem is adapted from [KernelBench](https://github.com/ScalingIntelligence/KernelBench/blob/main/KernelBench/level1/15_Matmul_for_lower_triangular_matrices.py)

Rank	User	Runtime (ms)	GPU	Date
1	Gusanidas	1.59	B200	about 2 months ago
2	sssuhasss	5.91	H100	9 months ago
3	doudi25	7.33	H200	28 days ago
4	Gusanidas	9.04	T4	about 2 months ago
5	Firojpaudel	9.85	H100	9 months ago
6	Krishna-D-Mohan	13.00	H100	9 months ago
7	a-hamdi	13.33	H100	9 months ago
8	648trindade	20.62	H100	6 months ago
9	doudi25	76.89	T4	28 days ago
10	Firojpaudel	93.67	T4	9 months ago
11	a-hamdi	120.70	T4	9 months ago
12	knightron0	228.97	T4	10 months ago