Question about buffer fuction that used in documentation of Monte Carlo ROC Simulation in Help Center

When I was reading the example of the Monte Carlo ROC Simulation in Help Center of MathWorks. In the Loop Over Pulses section, there is a buffer function is use, which is

rcv_pulses = buffer(rcv_pulses(matchingdelay+1:end),size(rcv_pulses,1));

where rcv_pulses is a matrix and matchingdelay equals 19. So, as far as I know the output of the new rcv_pulses is a also matrix with matrix. But when I checked the code the rcv_pulses(matchingdelay+1:end) is a vector, why after the buffer function, it again becomes a matrix? Could anyone help me here and explain how this buffer function works here?

Answer 1

[奥 刘]

I found that it just added 0 at the last column.