float_epsilon

# Miscellaneous¶↑

float_epsilon
Syntax:
h.float_epsilon = 1e-11
Description:

The default value is 1e-11

Allows somewhat safer NEURON logical comparisons and integer truncation for floating point numbers. Most NEURON comparisons are treated as true if they are within float_epsilon of being true. eg.

from neuron import h

h("""
proc count_to_1() {for (i = 0; i < 1; i += 0.1) \$o1.__call__(i)}
""")

def print_i(i):
print('%3g %g' % (i, int(10*i)))

rv = h.count_to_1(print_i)

h.float_epsilon = 0

# two bugs due to roundoff
rv = h.count_to_1(print_i)


Warning

This has no effect on Python comparisons, which is why the example uses a HOC procedure.

Warning

I certainly haven’t gotten every floating comparison in the program to use float_epsilon but I have most of them including all HOC interpreter logical operations, int, array indices, and Vector logic methods.