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quadratic.go
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/
quadratic.go
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//-----------------------------------------------------------------------------
/*
Quadratic Solver
*/
//-----------------------------------------------------------------------------
package sdf
import "math"
//-----------------------------------------------------------------------------
type qSoln int
const (
zeroSoln qSoln = iota
oneSoln
twoSoln
infSoln
)
// Return the real solutions of ax^2 + bx + c = 0
func quadratic(a, b, c float64) ([]float64, qSoln) {
// TODO Fix all comparisons to 0
if a == 0 {
if b == 0 {
if c == 0 {
// a = 0, b = 0, c = 0
return nil, infSoln
}
// a = 0, b = 0, c != 0
return nil, zeroSoln
}
// a =0, b != 0, c != 0
return []float64{-c / b}, oneSoln
}
det := b*b - 4*a*c
if det < 0 {
return nil, zeroSoln
}
x := -b / (2 * a)
if det == 0 {
return []float64{x}, oneSoln
}
d := math.Sqrt(det) / (2 * a)
return []float64{x + d, x - d}, twoSoln
}
//-----------------------------------------------------------------------------