This error means the computation is trying to compute something like integer^integer with an exponent larger than 2^32. The resulting integer would take up several Gigabytes of memory and take a long time to compute – and be pretty much useless for virtually all applications. So the symbolic engine flat out refuses to start computing it.
>> sym(23)^(2^42)
Error using symengine (line 58)
The integer is too large in context.
You could try calling rank(vpa(A)) instead of rank(A). But it's quite likely your input would then cause intermediate results to be (rounded to) infinity or 0.0, making the result useless.
