
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	GPU	Date
1	Gusanidas	1.59 ms	B200	5 months ago
2	sssuhasss	5.91 ms	H100	12 months ago
3	doudi25	7.33 ms	H200	4 months ago
4	Gusanidas	9.04 ms	T4	5 months ago
5	Firojpaudel	9.85 ms	H100	12 months ago
6	Krishna-D-Mohan	13.00 ms	H100	12 months ago
7	a-hamdi	13.33 ms	H100	about 1 year ago
8	648trindade	20.62 ms	H100	9 months ago
9	doudi25	76.89 ms	T4	4 months ago
10	Firojpaudel	93.67 ms	T4	12 months ago
11	a-hamdi	120.70 ms	T4	about 1 year ago
12	knightron0	228.97 ms	T4	about 1 year ago
13	wtwver	375.86 ms	T4	about 2 months ago
14	Rajat123456789	388.79 ms	T4	3 months ago