Destination given bearing on a great circle

Average Error: 0.2 → 0.1

Time: 30.0s

Precision: binary64

Cost: 97088

Math

\[\lambda_1 + \tan^{-1}_* \frac{\left(\sin theta \cdot \sin delta\right) \cdot \cos \phi_1}{\cos delta - \sin \phi_1 \cdot \sin \sin^{-1} \left(\sin \phi_1 \cdot \cos delta + \left(\cos \phi_1 \cdot \sin delta\right) \cdot \cos theta\right)} \]

↓

\[\lambda_1 + \tan^{-1}_* \frac{\sin theta \cdot \left(\sin delta \cdot \cos \phi_1\right)}{\mathsf{fma}\left(\sin \sin^{-1} \left(\mathsf{fma}\left(\sin delta, \cos \phi_1 \cdot \cos theta, \cos delta \cdot \sin \phi_1\right)\right), -\sin \phi_1, \cos delta\right)} \]

FPCore

(FPCore (lambda1 phi1 phi2 delta theta)
 :precision binary64
 (+
  lambda1
  (atan2
   (* (* (sin theta) (sin delta)) (cos phi1))
   (-
    (cos delta)
    (*
     (sin phi1)
     (sin
      (asin
       (+
        (* (sin phi1) (cos delta))
        (* (* (cos phi1) (sin delta)) (cos theta))))))))))

↓

(FPCore (lambda1 phi1 phi2 delta theta)
 :precision binary64
 (+
  lambda1
  (atan2
   (* (sin theta) (* (sin delta) (cos phi1)))
   (fma
    (sin
     (asin
      (fma (sin delta) (* (cos phi1) (cos theta)) (* (cos delta) (sin phi1)))))
    (- (sin phi1))
    (cos delta)))))

C

double code(double lambda1, double phi1, double phi2, double delta, double theta) {
	return lambda1 + atan2(((sin(theta) * sin(delta)) * cos(phi1)), (cos(delta) - (sin(phi1) * sin(asin(((sin(phi1) * cos(delta)) + ((cos(phi1) * sin(delta)) * cos(theta))))))));
}

↓

double code(double lambda1, double phi1, double phi2, double delta, double theta) {
	return lambda1 + atan2((sin(theta) * (sin(delta) * cos(phi1))), fma(sin(asin(fma(sin(delta), (cos(phi1) * cos(theta)), (cos(delta) * sin(phi1))))), -sin(phi1), cos(delta)));
}

Julia

function code(lambda1, phi1, phi2, delta, theta)
	return Float64(lambda1 + atan(Float64(Float64(sin(theta) * sin(delta)) * cos(phi1)), Float64(cos(delta) - Float64(sin(phi1) * sin(asin(Float64(Float64(sin(phi1) * cos(delta)) + Float64(Float64(cos(phi1) * sin(delta)) * cos(theta)))))))))
end

↓

function code(lambda1, phi1, phi2, delta, theta)
	return Float64(lambda1 + atan(Float64(sin(theta) * Float64(sin(delta) * cos(phi1))), fma(sin(asin(fma(sin(delta), Float64(cos(phi1) * cos(theta)), Float64(cos(delta) * sin(phi1))))), Float64(-sin(phi1)), cos(delta))))
end

Wolfram

code[lambda1_, phi1_, phi2_, delta_, theta_] := N[(lambda1 + N[ArcTan[N[(N[(N[Sin[theta], $MachinePrecision] * N[Sin[delta], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision] / N[(N[Cos[delta], $MachinePrecision] - N[(N[Sin[phi1], $MachinePrecision] * N[Sin[N[ArcSin[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Cos[delta], $MachinePrecision]), $MachinePrecision] + N[(N[(N[Cos[phi1], $MachinePrecision] * N[Sin[delta], $MachinePrecision]), $MachinePrecision] * N[Cos[theta], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]

↓

code[lambda1_, phi1_, phi2_, delta_, theta_] := N[(lambda1 + N[ArcTan[N[(N[Sin[theta], $MachinePrecision] * N[(N[Sin[delta], $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(N[Sin[N[ArcSin[N[(N[Sin[delta], $MachinePrecision] * N[(N[Cos[phi1], $MachinePrecision] * N[Cos[theta], $MachinePrecision]), $MachinePrecision] + N[(N[Cos[delta], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] * (-N[Sin[phi1], $MachinePrecision]) + N[Cos[delta], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]

Derivation

1. Initial program 0.2

   \[\lambda_1 + \tan^{-1}_* \frac{\left(\sin theta \cdot \sin delta\right) \cdot \cos \phi_1}{\cos delta - \sin \phi_1 \cdot \sin \sin^{-1} \left(\sin \phi_1 \cdot \cos delta + \left(\cos \phi_1 \cdot \sin delta\right) \cdot \cos theta\right)} \]

2. Simplified 0.1

   \[\leadsto \color{blue}{\lambda_1 + \tan^{-1}_* \frac{\sin theta \cdot \left(\sin delta \cdot \cos \phi_1\right)}{\mathsf{fma}\left(\sin \sin^{-1} \left(\mathsf{fma}\left(\sin delta, \cos \phi_1 \cdot \cos theta, \cos delta \cdot \sin \phi_1\right)\right), -\sin \phi_1, \cos delta\right)}} \]
   Proof
   (+.f64 lambda1 (atan2.f64 (*.f64 (sin.f64 theta) (*.f64 (sin.f64 delta) (cos.f64 phi1))) (fma.f64 (sin.f64 (asin.f64 (fma.f64 (sin.f64 delta) (*.f64 (cos.f64 phi1) (cos.f64 theta)) (*.f64 (cos.f64 delta) (sin.f64 phi1))))) (neg.f64 (sin.f64 phi1)) (cos.f64 delta)))): 0 points increase in error, 0 points decrease in error
   (+.f64 lambda1 (atan2.f64 (Rewrite<= associate-*l*_binary64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1))) (fma.f64 (sin.f64 (asin.f64 (fma.f64 (sin.f64 delta) (*.f64 (cos.f64 phi1) (cos.f64 theta)) (*.f64 (cos.f64 delta) (sin.f64 phi1))))) (neg.f64 (sin.f64 phi1)) (cos.f64 delta)))): 0 points increase in error, 0 points decrease in error
   (+.f64 lambda1 (atan2.f64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1)) (fma.f64 (sin.f64 (asin.f64 (fma.f64 (sin.f64 delta) (Rewrite<= *-commutative_binary64 (*.f64 (cos.f64 theta) (cos.f64 phi1))) (*.f64 (cos.f64 delta) (sin.f64 phi1))))) (neg.f64 (sin.f64 phi1)) (cos.f64 delta)))): 0 points increase in error, 0 points decrease in error
   (+.f64 lambda1 (atan2.f64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1)) (fma.f64 (sin.f64 (asin.f64 (fma.f64 (sin.f64 delta) (*.f64 (cos.f64 theta) (cos.f64 phi1)) (Rewrite<= *-commutative_binary64 (*.f64 (sin.f64 phi1) (cos.f64 delta)))))) (neg.f64 (sin.f64 phi1)) (cos.f64 delta)))): 0 points increase in error, 0 points decrease in error
   (+.f64 lambda1 (atan2.f64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1)) (fma.f64 (sin.f64 (asin.f64 (Rewrite<= fma-def_binary64 (+.f64 (*.f64 (sin.f64 delta) (*.f64 (cos.f64 theta) (cos.f64 phi1))) (*.f64 (sin.f64 phi1) (cos.f64 delta)))))) (neg.f64 (sin.f64 phi1)) (cos.f64 delta)))): 0 points increase in error, 0 points decrease in error
   (+.f64 lambda1 (atan2.f64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1)) (fma.f64 (sin.f64 (asin.f64 (+.f64 (Rewrite=> *-commutative_binary64 (*.f64 (*.f64 (cos.f64 theta) (cos.f64 phi1)) (sin.f64 delta))) (*.f64 (sin.f64 phi1) (cos.f64 delta))))) (neg.f64 (sin.f64 phi1)) (cos.f64 delta)))): 13 points increase in error, 0 points decrease in error
   (+.f64 lambda1 (atan2.f64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1)) (fma.f64 (sin.f64 (asin.f64 (+.f64 (Rewrite<= associate-*r*_binary64 (*.f64 (cos.f64 theta) (*.f64 (cos.f64 phi1) (sin.f64 delta)))) (*.f64 (sin.f64 phi1) (cos.f64 delta))))) (neg.f64 (sin.f64 phi1)) (cos.f64 delta)))): 0 points increase in error, 13 points decrease in error
   (+.f64 lambda1 (atan2.f64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1)) (fma.f64 (sin.f64 (asin.f64 (+.f64 (Rewrite<= *-commutative_binary64 (*.f64 (*.f64 (cos.f64 phi1) (sin.f64 delta)) (cos.f64 theta))) (*.f64 (sin.f64 phi1) (cos.f64 delta))))) (neg.f64 (sin.f64 phi1)) (cos.f64 delta)))): 0 points increase in error, 0 points decrease in error
   (+.f64 lambda1 (atan2.f64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1)) (fma.f64 (sin.f64 (asin.f64 (Rewrite<= +-commutative_binary64 (+.f64 (*.f64 (sin.f64 phi1) (cos.f64 delta)) (*.f64 (*.f64 (cos.f64 phi1) (sin.f64 delta)) (cos.f64 theta)))))) (neg.f64 (sin.f64 phi1)) (cos.f64 delta)))): 0 points increase in error, 0 points decrease in error
   (+.f64 lambda1 (atan2.f64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1)) (Rewrite<= fma-def_binary64 (+.f64 (*.f64 (sin.f64 (asin.f64 (+.f64 (*.f64 (sin.f64 phi1) (cos.f64 delta)) (*.f64 (*.f64 (cos.f64 phi1) (sin.f64 delta)) (cos.f64 theta))))) (neg.f64 (sin.f64 phi1))) (cos.f64 delta))))): 0 points increase in error, 0 points decrease in error
   (+.f64 lambda1 (atan2.f64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1)) (+.f64 (Rewrite<= *-commutative_binary64 (*.f64 (neg.f64 (sin.f64 phi1)) (sin.f64 (asin.f64 (+.f64 (*.f64 (sin.f64 phi1) (cos.f64 delta)) (*.f64 (*.f64 (cos.f64 phi1) (sin.f64 delta)) (cos.f64 theta))))))) (cos.f64 delta)))): 0 points increase in error, 0 points decrease in error
   (+.f64 lambda1 (atan2.f64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1)) (Rewrite<= +-commutative_binary64 (+.f64 (cos.f64 delta) (*.f64 (neg.f64 (sin.f64 phi1)) (sin.f64 (asin.f64 (+.f64 (*.f64 (sin.f64 phi1) (cos.f64 delta)) (*.f64 (*.f64 (cos.f64 phi1) (sin.f64 delta)) (cos.f64 theta)))))))))): 0 points increase in error, 0 points decrease in error
   (+.f64 lambda1 (atan2.f64 (*.f64 (*.f64 (sin.f64 theta) (sin.f64 delta)) (cos.f64 phi1)) (Rewrite<= cancel-sign-sub-inv_binary64 (-.f64 (cos.f64 delta) (*.f64 (sin.f64 phi1) (sin.f64 (asin.f64 (+.f64 (*.f64 (sin.f64 phi1) (cos.f64 delta)) (*.f64 (*.f64 (cos.f64 phi1) (sin.f64 delta)) (cos.f64 theta)))))))))): 0 points increase in error, 0 points decrease in error

3. Final simplification 0.1

   \[\leadsto \lambda_1 + \tan^{-1}_* \frac{\sin theta \cdot \left(\sin delta \cdot \cos \phi_1\right)}{\mathsf{fma}\left(\sin \sin^{-1} \left(\mathsf{fma}\left(\sin delta, \cos \phi_1 \cdot \cos theta, \cos delta \cdot \sin \phi_1\right)\right), -\sin \phi_1, \cos delta\right)} \]

Alternatives

Alternative 1
Error	0.1
Cost	77952

\[\lambda_1 + \tan^{-1}_* \frac{\cos \phi_1 \cdot \left(\sin theta \cdot \sin delta\right)}{\cos delta - \sin \phi_1 \cdot \mathsf{fma}\left(\cos delta, \sin \phi_1, \left(\sin delta \cdot \cos \phi_1\right) \cdot \cos theta\right)} \]

Alternative 2
Error	0.2
Cost	71680

\[\lambda_1 + \tan^{-1}_* \frac{\sin delta \cdot \left(\sin theta \cdot \cos \phi_1\right)}{\cos delta - \sin \phi_1 \cdot \left(\cos delta \cdot \sin \phi_1 + \sin delta \cdot \left(\cos \phi_1 \cdot \cos theta\right)\right)} \]

Alternative 3
Error	0.2
Cost	71680

\[\lambda_1 + \tan^{-1}_* \frac{\sin theta \cdot \left(\sin delta \cdot \cos \phi_1\right)}{\cos delta - \sin \phi_1 \cdot \left(\cos delta \cdot \sin \phi_1 + \sin delta \cdot \left(\cos \phi_1 \cdot \cos theta\right)\right)} \]

Alternative 4
Error	3.6
Cost	65152

\[\lambda_1 + \tan^{-1}_* \frac{\cos \phi_1 \cdot \left(\sin theta \cdot \sin delta\right)}{\cos delta - \sin \phi_1 \cdot \left(\sin delta \cdot \cos \phi_1 + \cos delta \cdot \sin \phi_1\right)} \]

Alternative 5
Error	5.1
Cost	45504

\[\lambda_1 + \tan^{-1}_* \frac{\cos \phi_1 \cdot \left(\sin theta \cdot \sin delta\right)}{\cos delta - {\sin \phi_1}^{2}} \]

Alternative 6
Error	5.4
Cost	45444

\[\begin{array}{l} t_1 := \sin delta \cdot \left(\sin theta \cdot \cos \phi_1\right)\\ \mathbf{if}\;delta \leq -0.0038:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{\mathsf{log1p}\left(\mathsf{expm1}\left(t_1\right)\right)}{\cos delta}\\ \mathbf{elif}\;delta \leq 1.3 \cdot 10^{-21}:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{\sin theta \cdot \left(\sin delta \cdot \cos \phi_1\right)}{\cos \phi_1 \cdot \cos \phi_1}\\ \mathbf{else}:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{t_1}{\cos delta}\\ \end{array} \]

Alternative 7
Error	5.4
Cost	39305

\[\begin{array}{l} \mathbf{if}\;delta \leq -0.024 \lor \neg \left(delta \leq 1.3 \cdot 10^{-21}\right):\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{\sin delta \cdot \left(\sin theta \cdot \cos \phi_1\right)}{\cos delta}\\ \mathbf{else}:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{\sin theta \cdot \left(\sin delta \cdot \cos \phi_1\right)}{\cos \phi_1 \cdot \cos \phi_1}\\ \end{array} \]

Alternative 8
Error	5.4
Cost	39241

\[\begin{array}{l} \mathbf{if}\;delta \leq -0.0038 \lor \neg \left(delta \leq 1.3 \cdot 10^{-21}\right):\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{\sin delta \cdot \left(\sin theta \cdot \cos \phi_1\right)}{\cos delta}\\ \mathbf{else}:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{\cos \phi_1 \cdot \left(\sin theta \cdot \sin delta\right)}{{\cos \phi_1}^{2}}\\ \end{array} \]

Alternative 9
Error	7.4
Cost	32512

\[\lambda_1 + \tan^{-1}_* \frac{\sin delta \cdot \left(\sin theta \cdot \cos \phi_1\right)}{\cos delta} \]

Alternative 10
Error	8.1
Cost	26377

\[\begin{array}{l} \mathbf{if}\;theta \leq -6 \cdot 10^{-65} \lor \neg \left(theta \leq 1.65 \cdot 10^{-15}\right):\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{\sin theta \cdot \sin delta}{\cos delta}\\ \mathbf{else}:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{\cos \phi_1 \cdot \left(theta \cdot \sin delta\right)}{\cos delta}\\ \end{array} \]

Alternative 11
Error	14.0
Cost	26248

\[\begin{array}{l} \mathbf{if}\;delta \leq -8.8 \cdot 10^{+72}:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{theta \cdot \sin delta}{\cos delta}\\ \mathbf{elif}\;delta \leq 8.4 \cdot 10^{+76}:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{\sin theta \cdot delta}{\cos delta}\\ \mathbf{else}:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{theta \cdot \left|\sin delta\right|}{\cos delta}\\ \end{array} \]

Alternative 12
Error	8.9
Cost	25984

\[\lambda_1 + \tan^{-1}_* \frac{\sin theta \cdot \sin delta}{\cos delta} \]

Alternative 13
Error	12.6
Cost	19849

\[\begin{array}{l} \mathbf{if}\;theta \leq -7800000 \lor \neg \left(theta \leq 0.6\right):\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{\sin theta \cdot delta}{\cos delta}\\ \mathbf{else}:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{theta \cdot \sin delta}{\cos delta}\\ \end{array} \]

Alternative 14
Error	15.2
Cost	19848

\[\begin{array}{l} \mathbf{if}\;theta \leq -1.7 \cdot 10^{+152}:\\ \;\;\;\;\lambda_1\\ \mathbf{elif}\;theta \leq 4.7 \cdot 10^{+25}:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{theta \cdot \sin delta}{\cos delta}\\ \mathbf{else}:\\ \;\;\;\;\lambda_1\\ \end{array} \]

Alternative 15
Error	19.6
Cost	13448

\[\begin{array}{l} \mathbf{if}\;theta \leq -4 \cdot 10^{+159}:\\ \;\;\;\;\lambda_1\\ \mathbf{elif}\;theta \leq 2.3 \cdot 10^{-244}:\\ \;\;\;\;\lambda_1 + \tan^{-1}_* \frac{theta \cdot delta}{\cos delta}\\ \mathbf{else}:\\ \;\;\;\;\lambda_1\\ \end{array} \]

Alternative 16
Error	19.3
Cost	64

\[\lambda_1 \]

Reproduce

herbie shell --seed 2022343 
(FPCore (lambda1 phi1 phi2 delta theta)
  :name "Destination given bearing on a great circle"
  :precision binary64
  (+ lambda1 (atan2 (* (* (sin theta) (sin delta)) (cos phi1)) (- (cos delta) (* (sin phi1) (sin (asin (+ (* (sin phi1) (cos delta)) (* (* (cos phi1) (sin delta)) (cos theta))))))))))