Recursion Depth
---------------

Calc uses recursion in many of its calculations.  Emacs Lisp keeps a
variable `max-lisp-eval-depth' which limits the amount of recursion
possible in an attempt to recover from program bugs.  If a calculation
ever halts incorrectly with the message "Computation got stuck or ran
too long," use the `M' command (`calc-more-recursion-depth') to
increase this limit.  (Of course, this will not help if the
calculation really did get stuck due to some problem inside Calc.)

The limit is always increased (multiplied) by a factor of two.  There
is also an `I M' (`calc-less-recursion-depth') command which decreases
this limit by a factor of two, down to a minimum value of 200.  The
default value is 1000.

These commands also double or halve `max-specpdl-size', another
internal Lisp recursion limit.  The minimum value for this limit is
600.