func TestRootFdf(t *testing.T) {
var maxIter int = 100
var x float64 = 5.0
var rExpected float64 = math.Sqrt(5.0)
qp := &QuadraticParams{
A: 1.0,
B: 0.0,
C: -5.0,
}
f := &gogsl.GslFunctionFdf{
Function: Quadratic,
Derivative: QuadraticDeriv,
Fdf: QuadraticFdf,
Params: qp,
}
gogsl.InitializeGslFunctionFdf(f)
T := root.GSL_ROOT_FDFSOLVER_NEWTON
s := root.FdfsolverAlloc(T)
root.FdfsolverSet(s, f, x)
fmt.Printf("using %s method\n", root.FdfsolverName(s))
fmt.Printf("%-5s %10s %10s %10s\n", "iter", "root", "err", "err(est)")
iter := 0
for {
iter += 1
root.FdfsolverIterate(s)
x0 := x
x = root.FdfsolverRoot(s)
status := gogsl.GslError(root.TestDelta(x, x0, 0, 1e-3))
if status == gogsl.GSL_SUCCESS {
fmt.Printf("Converged:\n")
}
fmt.Printf("%5d %10.7f %+10.7f %10.7f\n", iter, x, x-rExpected, x-x0)
if status != gogsl.GSL_CONTINUE || iter >= maxIter {
break
}
}
}
func FdfsolverSet(s *GslRootFdfsolver, fdf *gogsl.GslFunctionFdf, root float64) int32 {
gogsl.InitializeGslFunctionFdf(fdf)
return int32(C.gsl_root_fdfsolver_set((*C.gsl_root_fdfsolver)(unsafe.Pointer(s.Ptr())), (*C.gsl_function_fdf)(unsafe.Pointer(fdf.CPtr())), C.double(root)))
}