Why do I get a "Cannot solve algebraic loop involving block ..." error when I have a feedback look in my design?
This is because you must have a delay element in your feedback loop.
Some components such as the Addressable Shift Register look like an asynchronous path in System Generator for DSP.
To solve the problem, you must add delay in the feedback path. This can be done by adding latency to a component in the feedback path, or by adding a register to the feedback path.
If you are seeing this problem when using a Black Box, please see (Xilinx Answer 18759).