floatgmin: a circuit with no floating nodes solves to the exact textbook value

* (exec-spice "ngspice -b %s")

* pure resistive divider: v(mid) = 5 * 2k/(1k+2k) = 3.3333... V exactly.
* nothing floats, so floatgmin must not touch the matrix and the answer is exact.
v1 in 0 5
r1 in mid 1k
r2 mid 0 2k

.control
define mismatch(a,b,err) abs(a-b)>err
let fail_count = 0

op
if mismatch(v(mid), 10.0/3.0, 1e-9)
  let vt = v(mid)
  echo "ERROR: v(mid) = $&vt but should be 3.33333333 V"
  let fail_count = fail_count + 1
end

if fail_count > 0
  echo "ERROR: $&fail_count of 1 tests failed"
  quit 1
else
  echo "INFO: $&fail_count of 1 tests failed"
  quit 0
end
.endc
.end
