Hi All,
I am trying to implement a MIMO algorithm in a custom Python block
with vectors in & out. What i want to accomplish in this custom block is
to first correlate the input vectors with a given pilot matrix(e.g.
vector size 2), for example, the pilot length could be 1000, the
correlation will be a 2x2 matrix, then if the correlation satisfies some
condition, the block will output this 2x2 matrix. My questions are:

Since the output depends on if a pilot signal is transmitted, we
should use general block. But if I want this block to output all the
correlations whether the condition is satisfied or not, then what type
of block should i use? I am confused here because after the first 1000
vectors are received, the block will produce 2 vectors for every input
vector, so should i use an interpolation block? 
How do i use forecast and set_history functions in a Python block?
Since I need 1000 input vectors for every 2 output vectors(if there are
any), So the history should be set to 1000. I guess I can make it work
without using these 2 functions by introducing a self.previous variable
to store the last 999 input vectors, am I right? 
Are there any python block examples that might help me?
Thank you!
best,
Hai