is the input signal a matrix?

if so, imagine that the matrix is named "A" then you have to follow the instruction below:

1- find the peak: to do this, you have to calculate "B = sign(diff(A))". this command give you a matrix consists of "+1" nad "-1". To clrarify, "+1" means that the next value is greater than current value. So you have to find the situation that changes from "+1" to "-1" which is the peak.

2- To find the peak from matrix B, simply use "C = findsubmat(B, [+1 -1])". The position of all the peaks aare stored in Matrix C.

Of course, pay attention that you have to check the first and the last elements of Signal (Matrix B) whether they are peak or not.