Matrix operation is an important problem in the field of numerical analysis. Decomposition of a matrix into a combination of simple matrices can simplify the operation of the matrix in theory and practical application.
The most important formula, others can use this to deduce that x has a derivative when Y = AXB Y = A*X*BY=AXB, and the formula (1) dydx = atbt \ frac {dy} {dx} = at * bttdxdy = atbt and xtx txt.
If you want to calculate the value of d Y d X \frac{dY}{dX}dXdY in Y = XB Y = X*BY=XB, you can substitute A = E A =EA=E into the formula (1), where DYDX = BT \ frac {dy} {dx} = B, there is a trick. You can try the specific rules by yourself.