Memorizing signal values

The block saves the signal (s) according to the following algorithm:

where x_1,i(t), x_2,i(t) are the i-th elements of the first and second vector input signals, y_i(t) is the i-th element of the vector output signal. In other words, if a non-zero signal is applied to the second input, then the value of the signal at the output is equal to the value of the signal at the first input. At a zero signal at the second input, the block "memorizes" the value of the first input and then the output does not change (until a positive signal is fed to the second input again).