- class GUIMath
obj = h.GUIMath()
Contains functions which calculate common relationships between graphics objects.
d = guimath.d2line(xpoint, ypoint, xline0, yline0, xline1, yline1)
Return distance between the point (xpoint,ypoint) and the (infinitely long) line defined by the 0 and 1 points.
d = guimath.d2line_seg(xpoint, ypoint, xline0, yline0, xline1, yline1)
Return distance between the point (xpoint, ypoint) and the line segment line defined by the 0 and 1 points.
boolean = guimath.inside(xpoint, ypoint, left, bottom, right, top)
return True if the point is inside the box, False otherwise
mode = guimath.feround()
lastmode = guimath.feround(mode)
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.
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)
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