The TOL worksheet variable controls the precision to which integrals
and derivatives are evaluated.
TOL also controls convergence criteria in Solve
Blocks and in the root function.
The two most recent estimates of a solution must differ by less than the
built-in variable TOL.
CTOL
The CTOL worksheet variable controls how closely a constraint
in a Solve Block must be met for a solution
to be acceptable, using any of the optimizing functions: Minimize,
Maximize,
Find, or Minerr.
For example, a constraint such as x < 2 must
be satisfied to within CTOL before a solution is returned. If CTOL
= 0.001 (the default), this constraint is satisfied if x
< 2.001.
Controlling the Precision of Solutions
Change the value of TOL and
CTOL to control the precision of solutions. The larger the value,
the less precise the solution may be. Smaller values produce more precise
solutions, but may increase calculation time, or make it impossible for
an operation to converge. An error message may result when the numerical
properties of the expression are such that a solution asymptotically approaches
a number that exceeds the acceptance threshold set by TOL.
