solver

type Euler struct {
	F func(x, y float64) (float64, error) // calculator for f(x,y) = y'
}

type Exact struct {
	// F is a function y(x) = f(x), the solution for the initial value problem,
	// requires a constant, that is calculated with initial values
	F func(x, c float64) (float64, error)
	// C calculates the constant for the F
	C func(x0, y0 float64) (float64, error)
}

type ImprovedEuler struct {
	F func(x, y float64) (float64, error) // calculator for f(x,y) = y'
}

type Interface interface {
	Solve(stepSize, x0, y0, xEnd float64) (line num.Line, err error)
}

type RungeKutta struct {
	F func(x, y float64) (float64, error) // calculator for f(x,y) = y'
}