GUIMath

d2line · d2line_seg · feround · inside

GUIMath

class GUIMath

Python

Syntax:

obj = n.GUIMath()

Description:

Contains functions which calculate common relationships between graphics objects.

HOC

Syntax:

obj = new GUIMath()

Description:

Contains functions which calculate common relationships between graphics objects.

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GUIMath.d2line()

Python

Syntax:

d = gm.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.

HOC

Syntax:

d = gm.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.

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GUIMath.d2line_seg()

Python

Syntax:

d = gm.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.

HOC

Syntax:

d = gm.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.

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GUIMath.inside()

Python

Syntax:

boolean = gm.inside(xpoint, ypoint, left, bottom, right, top)

Description:

return True if the point is inside the box, False otherwise

HOC

Syntax:

boolean = gm.inside(xpoint, ypoint, left, bottom, right, top)

Description:

return 1 if the point is inside the box, 0 otherwise

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GUIMath.feround()

Python

Syntax:

mode = gm.feround()

lastmode = gm.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:

from neuron import n

gm = n.GUIMath()
print(f'default rounding mode {gm.feround()}')

def test_round(mode):
    gm = n.GUIMath()
    old = gm.feround(mode)
    x = 0
    for i in range(1, 1_000_001):
        x += 0.1
    print(f'round mode {mode} x={x:25.17f}')
    gm.feround(old)

for i in range(1, 5):
    test_round(i)

Output:

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

HOC

Syntax:

mode = gm.feround()

lastmode = gm.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.

Example:

objref gm
gm = new GUIMath()
{printf("default rounding mode %d\n", gm.feround())}


proc test_round() {local i, old, x  localobj gm
        gm = new GUIMath()
        old = gm.feround($1)
        x = 0
        for i=1, 1000000 x += 0.1
        printf("rounding mode %d x=%25.17lf\n", $1, x)
        gm.feround(old)
}


for i=1, 4 test_round(i)