GUIMath

classes
   d2line         d2line_seg     feround        inside

SYNTAX

obj = new GUIMath()

DESCRIPTION

Contains functions which calculate common relationships between graphics objects.

d2line

GUIMath

SYNTAX

d = math.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.

d2line_seg

GUIMath

SYNTAX

d = math.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.

inside

GUIMath

SYNTAX

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

DESCRIPTION

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

feround

GUIMath

SYNTAX

mode = math.feround()
lastmode = math.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.

EXAMPLES

execute following 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)

neuron/general/classes/guimath.hel : May 13 2012