1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
|
.. _guimath:
GUIMath
-------
.. class:: GUIMath
Syntax:
``obj = h.GUIMath()``
Description:
Contains functions which calculate common relationships between graphics
objects.
----
.. method:: GUIMath.d2line
Syntax:
``d = guimath.d2line(xpoint, ypoint, xline0, yline0, xline1, yline1)``
Description:
Return distance between the point (xpoint,ypoint) and the (infinitely long)
line defined by the 0 and 1 points.
----
.. method:: GUIMath.d2line_seg
Syntax:
``d = guimath.d2line_seg(xpoint, ypoint, xline0, yline0, xline1, yline1)``
Description:
Return distance between the point (xpoint, ypoint) and the line segment
line defined by the 0 and 1 points.
----
.. method:: GUIMath.inside
Syntax:
``boolean = guimath.inside(xpoint, ypoint, left, bottom, right, top)``
Description:
return True if the point is inside the box, False otherwise
----
.. method:: GUIMath.feround
Syntax:
``mode = guimath.feround()``
``lastmode = guimath.feround(mode)``
Description:
Set the floating point rounding mode. Mode 1, 2, 3, 4 refers to
FE_DOWNWARD, FE_TONEAREST, FE_TOWARDZERO, FE_UPWARD respectively.
The default, and most accurate, mode is FE_TONEAREST.
The mode is changed only if the argument is 1-4. If there is no
support for this function the return value is 0.
This function is useful to determine if a simulation depends unduly
on double precision round-off error.
This affects calculations performed in both Python and HOC.
Example:
.. code::
from neuron import h
gm = h.GUIMath()
print('default rounding mode %d' % gm.feround())
def test_round(mode):
gm = h.GUIMath()
old = gm.feround(mode)
x = 0
for i in range(1, 1000001):
x += 0.1
print('round mode %d x=%25.17lf' % (mode, x))
gm.feround(old)
for i in range(1, 5):
test_round(i)
Output:
.. code-block::
none
default rounding mode 2
round mode 1 x= 99999.99999613071850035
round mode 2 x= 100000.00000133288267534
round mode 3 x= 99999.99999613071850035
round mode 4 x= 100000.00000432481465396
|
