Add unit matrix generation.

Signed-off-by: CyberZHG <CyberZHG@gmail.com>
Add inverse of the matrix.

Signed-off-by: CyberZHG <CyberZHG@gmail.com>
Change code style.

Signed-off-by: CyberZHG <CyberZHG@gmail.com>
Add LDU decompose.

Signed-off-by: CyberZHG <CyberZHG@gmail.com>
Add Crout decompose.

Signed-off-by: CyberZHG <CyberZHG@gmail.com>