
(FPCore (w h dX.u dX.v dY.u dY.v maxAniso)
:precision binary32
(let* ((t_0 (* (floor h) dX.v))
(t_1 (* (floor w) dY.u))
(t_2 (* (floor w) dX.u))
(t_3 (+ (* t_2 t_2) (* t_0 t_0)))
(t_4 (* (floor h) dY.v))
(t_5 (+ (* t_1 t_1) (* t_4 t_4)))
(t_6 (/ 1.0 (sqrt (fmax t_3 t_5)))))
(if (>= t_3 t_5) (* t_6 t_0) (* t_6 t_4))))
float code(float w, float h, float dX_46_u, float dX_46_v, float dY_46_u, float dY_46_v, float maxAniso) {
float t_0 = floorf(h) * dX_46_v;
float t_1 = floorf(w) * dY_46_u;
float t_2 = floorf(w) * dX_46_u;
float t_3 = (t_2 * t_2) + (t_0 * t_0);
float t_4 = floorf(h) * dY_46_v;
float t_5 = (t_1 * t_1) + (t_4 * t_4);
float t_6 = 1.0f / sqrtf(fmaxf(t_3, t_5));
float tmp;
if (t_3 >= t_5) {
tmp = t_6 * t_0;
} else {
tmp = t_6 * t_4;
}
return tmp;
}
function code(w, h, dX_46_u, dX_46_v, dY_46_u, dY_46_v, maxAniso) t_0 = Float32(floor(h) * dX_46_v) t_1 = Float32(floor(w) * dY_46_u) t_2 = Float32(floor(w) * dX_46_u) t_3 = Float32(Float32(t_2 * t_2) + Float32(t_0 * t_0)) t_4 = Float32(floor(h) * dY_46_v) t_5 = Float32(Float32(t_1 * t_1) + Float32(t_4 * t_4)) t_6 = Float32(Float32(1.0) / sqrt(((t_3 != t_3) ? t_5 : ((t_5 != t_5) ? t_3 : max(t_3, t_5))))) tmp = Float32(0.0) if (t_3 >= t_5) tmp = Float32(t_6 * t_0); else tmp = Float32(t_6 * t_4); end return tmp end
function tmp_2 = code(w, h, dX_46_u, dX_46_v, dY_46_u, dY_46_v, maxAniso) t_0 = floor(h) * dX_46_v; t_1 = floor(w) * dY_46_u; t_2 = floor(w) * dX_46_u; t_3 = (t_2 * t_2) + (t_0 * t_0); t_4 = floor(h) * dY_46_v; t_5 = (t_1 * t_1) + (t_4 * t_4); t_6 = single(1.0) / sqrt(max(t_3, t_5)); tmp = single(0.0); if (t_3 >= t_5) tmp = t_6 * t_0; else tmp = t_6 * t_4; end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left\lfloorh\right\rfloor \cdot dX.v\\
t_1 := \left\lfloorw\right\rfloor \cdot dY.u\\
t_2 := \left\lfloorw\right\rfloor \cdot dX.u\\
t_3 := t_2 \cdot t_2 + t_0 \cdot t_0\\
t_4 := \left\lfloorh\right\rfloor \cdot dY.v\\
t_5 := t_1 \cdot t_1 + t_4 \cdot t_4\\
t_6 := \frac{1}{\sqrt{\mathsf{max}\left(t_3, t_5\right)}}\\
\mathbf{if}\;t_3 \geq t_5:\\
\;\;\;\;t_6 \cdot t_0\\
\mathbf{else}:\\
\;\;\;\;t_6 \cdot t_4\\
\end{array}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 3 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (w h dX.u dX.v dY.u dY.v maxAniso)
:precision binary32
(let* ((t_0 (* (floor h) dX.v))
(t_1 (* (floor w) dY.u))
(t_2 (* (floor w) dX.u))
(t_3 (+ (* t_2 t_2) (* t_0 t_0)))
(t_4 (* (floor h) dY.v))
(t_5 (+ (* t_1 t_1) (* t_4 t_4)))
(t_6 (/ 1.0 (sqrt (fmax t_3 t_5)))))
(if (>= t_3 t_5) (* t_6 t_0) (* t_6 t_4))))
float code(float w, float h, float dX_46_u, float dX_46_v, float dY_46_u, float dY_46_v, float maxAniso) {
float t_0 = floorf(h) * dX_46_v;
float t_1 = floorf(w) * dY_46_u;
float t_2 = floorf(w) * dX_46_u;
float t_3 = (t_2 * t_2) + (t_0 * t_0);
float t_4 = floorf(h) * dY_46_v;
float t_5 = (t_1 * t_1) + (t_4 * t_4);
float t_6 = 1.0f / sqrtf(fmaxf(t_3, t_5));
float tmp;
if (t_3 >= t_5) {
tmp = t_6 * t_0;
} else {
tmp = t_6 * t_4;
}
return tmp;
}
function code(w, h, dX_46_u, dX_46_v, dY_46_u, dY_46_v, maxAniso) t_0 = Float32(floor(h) * dX_46_v) t_1 = Float32(floor(w) * dY_46_u) t_2 = Float32(floor(w) * dX_46_u) t_3 = Float32(Float32(t_2 * t_2) + Float32(t_0 * t_0)) t_4 = Float32(floor(h) * dY_46_v) t_5 = Float32(Float32(t_1 * t_1) + Float32(t_4 * t_4)) t_6 = Float32(Float32(1.0) / sqrt(((t_3 != t_3) ? t_5 : ((t_5 != t_5) ? t_3 : max(t_3, t_5))))) tmp = Float32(0.0) if (t_3 >= t_5) tmp = Float32(t_6 * t_0); else tmp = Float32(t_6 * t_4); end return tmp end
function tmp_2 = code(w, h, dX_46_u, dX_46_v, dY_46_u, dY_46_v, maxAniso) t_0 = floor(h) * dX_46_v; t_1 = floor(w) * dY_46_u; t_2 = floor(w) * dX_46_u; t_3 = (t_2 * t_2) + (t_0 * t_0); t_4 = floor(h) * dY_46_v; t_5 = (t_1 * t_1) + (t_4 * t_4); t_6 = single(1.0) / sqrt(max(t_3, t_5)); tmp = single(0.0); if (t_3 >= t_5) tmp = t_6 * t_0; else tmp = t_6 * t_4; end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left\lfloorh\right\rfloor \cdot dX.v\\
t_1 := \left\lfloorw\right\rfloor \cdot dY.u\\
t_2 := \left\lfloorw\right\rfloor \cdot dX.u\\
t_3 := t_2 \cdot t_2 + t_0 \cdot t_0\\
t_4 := \left\lfloorh\right\rfloor \cdot dY.v\\
t_5 := t_1 \cdot t_1 + t_4 \cdot t_4\\
t_6 := \frac{1}{\sqrt{\mathsf{max}\left(t_3, t_5\right)}}\\
\mathbf{if}\;t_3 \geq t_5:\\
\;\;\;\;t_6 \cdot t_0\\
\mathbf{else}:\\
\;\;\;\;t_6 \cdot t_4\\
\end{array}
\end{array}
(FPCore (w h dX.u dX.v dY.u dY.v maxAniso)
:precision binary32
(let* ((t_0 (* dX.v (floor h)))
(t_1 (* (floor w) dY.u))
(t_2 (* (floor h) dY.v))
(t_3 (+ (pow t_1 2.0) (pow t_2 2.0)))
(t_4 (* dX.u (floor w)))
(t_5 (+ (pow t_4 2.0) (pow t_0 2.0))))
(if (>= t_5 t_3)
(/
t_0
(pow (fmax (pow (hypot t_4 t_0) 2.0) (pow (hypot t_1 t_2) 2.0)) 0.5))
(* t_2 (/ 1.0 (sqrt (fmax t_5 t_3)))))))
float code(float w, float h, float dX_46_u, float dX_46_v, float dY_46_u, float dY_46_v, float maxAniso) {
float t_0 = dX_46_v * floorf(h);
float t_1 = floorf(w) * dY_46_u;
float t_2 = floorf(h) * dY_46_v;
float t_3 = powf(t_1, 2.0f) + powf(t_2, 2.0f);
float t_4 = dX_46_u * floorf(w);
float t_5 = powf(t_4, 2.0f) + powf(t_0, 2.0f);
float tmp;
if (t_5 >= t_3) {
tmp = t_0 / powf(fmaxf(powf(hypotf(t_4, t_0), 2.0f), powf(hypotf(t_1, t_2), 2.0f)), 0.5f);
} else {
tmp = t_2 * (1.0f / sqrtf(fmaxf(t_5, t_3)));
}
return tmp;
}
function code(w, h, dX_46_u, dX_46_v, dY_46_u, dY_46_v, maxAniso) t_0 = Float32(dX_46_v * floor(h)) t_1 = Float32(floor(w) * dY_46_u) t_2 = Float32(floor(h) * dY_46_v) t_3 = Float32((t_1 ^ Float32(2.0)) + (t_2 ^ Float32(2.0))) t_4 = Float32(dX_46_u * floor(w)) t_5 = Float32((t_4 ^ Float32(2.0)) + (t_0 ^ Float32(2.0))) tmp = Float32(0.0) if (t_5 >= t_3) tmp = Float32(t_0 / ((((hypot(t_4, t_0) ^ Float32(2.0)) != (hypot(t_4, t_0) ^ Float32(2.0))) ? (hypot(t_1, t_2) ^ Float32(2.0)) : (((hypot(t_1, t_2) ^ Float32(2.0)) != (hypot(t_1, t_2) ^ Float32(2.0))) ? (hypot(t_4, t_0) ^ Float32(2.0)) : max((hypot(t_4, t_0) ^ Float32(2.0)), (hypot(t_1, t_2) ^ Float32(2.0))))) ^ Float32(0.5))); else tmp = Float32(t_2 * Float32(Float32(1.0) / sqrt(((t_5 != t_5) ? t_3 : ((t_3 != t_3) ? t_5 : max(t_5, t_3)))))); end return tmp end
function tmp_2 = code(w, h, dX_46_u, dX_46_v, dY_46_u, dY_46_v, maxAniso) t_0 = dX_46_v * floor(h); t_1 = floor(w) * dY_46_u; t_2 = floor(h) * dY_46_v; t_3 = (t_1 ^ single(2.0)) + (t_2 ^ single(2.0)); t_4 = dX_46_u * floor(w); t_5 = (t_4 ^ single(2.0)) + (t_0 ^ single(2.0)); tmp = single(0.0); if (t_5 >= t_3) tmp = t_0 / (max((hypot(t_4, t_0) ^ single(2.0)), (hypot(t_1, t_2) ^ single(2.0))) ^ single(0.5)); else tmp = t_2 * (single(1.0) / sqrt(max(t_5, t_3))); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := dX.v \cdot \left\lfloorh\right\rfloor\\
t_1 := \left\lfloorw\right\rfloor \cdot dY.u\\
t_2 := \left\lfloorh\right\rfloor \cdot dY.v\\
t_3 := {t_1}^{2} + {t_2}^{2}\\
t_4 := dX.u \cdot \left\lfloorw\right\rfloor\\
t_5 := {t_4}^{2} + {t_0}^{2}\\
\mathbf{if}\;t_5 \geq t_3:\\
\;\;\;\;\frac{t_0}{{\left(\mathsf{max}\left({\left(\mathsf{hypot}\left(t_4, t_0\right)\right)}^{2}, {\left(\mathsf{hypot}\left(t_1, t_2\right)\right)}^{2}\right)\right)}^{0.5}}\\
\mathbf{else}:\\
\;\;\;\;t_2 \cdot \frac{1}{\sqrt{\mathsf{max}\left(t_5, t_3\right)}}\\
\end{array}
\end{array}
Initial program 76.4%
associate-*l/76.6%
fma-def76.6%
associate-*r*76.6%
fma-udef76.6%
Applied egg-rr76.6%
Applied egg-rr76.6%
Taylor expanded in w around 0 76.6%
unpow276.6%
unpow276.6%
swap-sqr76.6%
unpow276.6%
unpow276.6%
unpow276.6%
swap-sqr76.6%
unpow276.6%
unpow276.6%
unpow276.6%
swap-sqr76.6%
unpow276.6%
*-commutative76.6%
*-commutative76.6%
unpow276.6%
unpow276.6%
Simplified76.6%
Taylor expanded in w around 0 76.5%
*-commutative76.5%
unpow276.5%
unpow276.5%
swap-sqr76.5%
unpow276.5%
*-commutative76.5%
unpow276.5%
unpow276.5%
swap-sqr76.5%
unpow276.5%
*-commutative76.5%
unpow276.5%
unpow276.5%
swap-sqr76.6%
*-commutative76.6%
Simplified76.6%
Final simplification76.6%
(FPCore (w h dX.u dX.v dY.u dY.v maxAniso)
:precision binary32
(let* ((t_0 (* dX.v (floor h)))
(t_1 (+ (pow (* dX.u (floor w)) 2.0) (pow t_0 2.0)))
(t_2 (* (floor h) dY.v))
(t_3 (+ (pow (* (floor w) dY.u) 2.0) (pow t_2 2.0)))
(t_4 (sqrt (fmax t_1 t_3))))
(if (>= t_1 t_3) (/ 1.0 (/ t_4 t_0)) (* t_2 (/ 1.0 t_4)))))
float code(float w, float h, float dX_46_u, float dX_46_v, float dY_46_u, float dY_46_v, float maxAniso) {
float t_0 = dX_46_v * floorf(h);
float t_1 = powf((dX_46_u * floorf(w)), 2.0f) + powf(t_0, 2.0f);
float t_2 = floorf(h) * dY_46_v;
float t_3 = powf((floorf(w) * dY_46_u), 2.0f) + powf(t_2, 2.0f);
float t_4 = sqrtf(fmaxf(t_1, t_3));
float tmp;
if (t_1 >= t_3) {
tmp = 1.0f / (t_4 / t_0);
} else {
tmp = t_2 * (1.0f / t_4);
}
return tmp;
}
function code(w, h, dX_46_u, dX_46_v, dY_46_u, dY_46_v, maxAniso) t_0 = Float32(dX_46_v * floor(h)) t_1 = Float32((Float32(dX_46_u * floor(w)) ^ Float32(2.0)) + (t_0 ^ Float32(2.0))) t_2 = Float32(floor(h) * dY_46_v) t_3 = Float32((Float32(floor(w) * dY_46_u) ^ Float32(2.0)) + (t_2 ^ Float32(2.0))) t_4 = sqrt(((t_1 != t_1) ? t_3 : ((t_3 != t_3) ? t_1 : max(t_1, t_3)))) tmp = Float32(0.0) if (t_1 >= t_3) tmp = Float32(Float32(1.0) / Float32(t_4 / t_0)); else tmp = Float32(t_2 * Float32(Float32(1.0) / t_4)); end return tmp end
function tmp_2 = code(w, h, dX_46_u, dX_46_v, dY_46_u, dY_46_v, maxAniso) t_0 = dX_46_v * floor(h); t_1 = ((dX_46_u * floor(w)) ^ single(2.0)) + (t_0 ^ single(2.0)); t_2 = floor(h) * dY_46_v; t_3 = ((floor(w) * dY_46_u) ^ single(2.0)) + (t_2 ^ single(2.0)); t_4 = sqrt(max(t_1, t_3)); tmp = single(0.0); if (t_1 >= t_3) tmp = single(1.0) / (t_4 / t_0); else tmp = t_2 * (single(1.0) / t_4); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := dX.v \cdot \left\lfloorh\right\rfloor\\
t_1 := {\left(dX.u \cdot \left\lfloorw\right\rfloor\right)}^{2} + {t_0}^{2}\\
t_2 := \left\lfloorh\right\rfloor \cdot dY.v\\
t_3 := {\left(\left\lfloorw\right\rfloor \cdot dY.u\right)}^{2} + {t_2}^{2}\\
t_4 := \sqrt{\mathsf{max}\left(t_1, t_3\right)}\\
\mathbf{if}\;t_1 \geq t_3:\\
\;\;\;\;\frac{1}{\frac{t_4}{t_0}}\\
\mathbf{else}:\\
\;\;\;\;t_2 \cdot \frac{1}{t_4}\\
\end{array}
\end{array}
Initial program 76.4%
associate-*l/76.6%
fma-def76.6%
associate-*r*76.6%
fma-udef76.6%
Applied egg-rr76.5%
Taylor expanded in w around 0 76.5%
unpow276.6%
unpow276.6%
swap-sqr76.6%
unpow276.6%
unpow276.6%
unpow276.6%
swap-sqr76.6%
unpow276.6%
unpow276.6%
unpow276.6%
swap-sqr76.6%
unpow276.6%
*-commutative76.6%
*-commutative76.6%
unpow276.6%
unpow276.6%
Simplified76.5%
Taylor expanded in w around 0 76.4%
*-commutative76.5%
unpow276.5%
unpow276.5%
swap-sqr76.5%
unpow276.5%
*-commutative76.5%
unpow276.5%
unpow276.5%
swap-sqr76.5%
unpow276.5%
*-commutative76.5%
unpow276.5%
unpow276.5%
swap-sqr76.6%
*-commutative76.6%
Simplified76.5%
Final simplification76.5%
(FPCore (w h dX.u dX.v dY.u dY.v maxAniso)
:precision binary32
(let* ((t_0 (* dX.v (floor h)))
(t_1 (* (floor w) dY.u))
(t_2 (* (floor h) dY.v))
(t_3 (+ (pow t_1 2.0) (pow t_2 2.0)))
(t_4 (* dX.u (floor w)))
(t_5 (+ (pow t_4 2.0) (pow t_0 2.0))))
(if (>= t_5 t_3)
(/ 1.0 (/ (sqrt (fmax t_5 t_3)) t_0))
(*
t_2
(/
1.0
(pow
(fmax (pow (hypot t_4 t_0) 2.0) (pow (hypot t_2 t_1) 2.0))
0.5))))))
float code(float w, float h, float dX_46_u, float dX_46_v, float dY_46_u, float dY_46_v, float maxAniso) {
float t_0 = dX_46_v * floorf(h);
float t_1 = floorf(w) * dY_46_u;
float t_2 = floorf(h) * dY_46_v;
float t_3 = powf(t_1, 2.0f) + powf(t_2, 2.0f);
float t_4 = dX_46_u * floorf(w);
float t_5 = powf(t_4, 2.0f) + powf(t_0, 2.0f);
float tmp;
if (t_5 >= t_3) {
tmp = 1.0f / (sqrtf(fmaxf(t_5, t_3)) / t_0);
} else {
tmp = t_2 * (1.0f / powf(fmaxf(powf(hypotf(t_4, t_0), 2.0f), powf(hypotf(t_2, t_1), 2.0f)), 0.5f));
}
return tmp;
}
function code(w, h, dX_46_u, dX_46_v, dY_46_u, dY_46_v, maxAniso) t_0 = Float32(dX_46_v * floor(h)) t_1 = Float32(floor(w) * dY_46_u) t_2 = Float32(floor(h) * dY_46_v) t_3 = Float32((t_1 ^ Float32(2.0)) + (t_2 ^ Float32(2.0))) t_4 = Float32(dX_46_u * floor(w)) t_5 = Float32((t_4 ^ Float32(2.0)) + (t_0 ^ Float32(2.0))) tmp = Float32(0.0) if (t_5 >= t_3) tmp = Float32(Float32(1.0) / Float32(sqrt(((t_5 != t_5) ? t_3 : ((t_3 != t_3) ? t_5 : max(t_5, t_3)))) / t_0)); else tmp = Float32(t_2 * Float32(Float32(1.0) / ((((hypot(t_4, t_0) ^ Float32(2.0)) != (hypot(t_4, t_0) ^ Float32(2.0))) ? (hypot(t_2, t_1) ^ Float32(2.0)) : (((hypot(t_2, t_1) ^ Float32(2.0)) != (hypot(t_2, t_1) ^ Float32(2.0))) ? (hypot(t_4, t_0) ^ Float32(2.0)) : max((hypot(t_4, t_0) ^ Float32(2.0)), (hypot(t_2, t_1) ^ Float32(2.0))))) ^ Float32(0.5)))); end return tmp end
function tmp_2 = code(w, h, dX_46_u, dX_46_v, dY_46_u, dY_46_v, maxAniso) t_0 = dX_46_v * floor(h); t_1 = floor(w) * dY_46_u; t_2 = floor(h) * dY_46_v; t_3 = (t_1 ^ single(2.0)) + (t_2 ^ single(2.0)); t_4 = dX_46_u * floor(w); t_5 = (t_4 ^ single(2.0)) + (t_0 ^ single(2.0)); tmp = single(0.0); if (t_5 >= t_3) tmp = single(1.0) / (sqrt(max(t_5, t_3)) / t_0); else tmp = t_2 * (single(1.0) / (max((hypot(t_4, t_0) ^ single(2.0)), (hypot(t_2, t_1) ^ single(2.0))) ^ single(0.5))); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := dX.v \cdot \left\lfloorh\right\rfloor\\
t_1 := \left\lfloorw\right\rfloor \cdot dY.u\\
t_2 := \left\lfloorh\right\rfloor \cdot dY.v\\
t_3 := {t_1}^{2} + {t_2}^{2}\\
t_4 := dX.u \cdot \left\lfloorw\right\rfloor\\
t_5 := {t_4}^{2} + {t_0}^{2}\\
\mathbf{if}\;t_5 \geq t_3:\\
\;\;\;\;\frac{1}{\frac{\sqrt{\mathsf{max}\left(t_5, t_3\right)}}{t_0}}\\
\mathbf{else}:\\
\;\;\;\;t_2 \cdot \frac{1}{{\left(\mathsf{max}\left({\left(\mathsf{hypot}\left(t_4, t_0\right)\right)}^{2}, {\left(\mathsf{hypot}\left(t_2, t_1\right)\right)}^{2}\right)\right)}^{0.5}}\\
\end{array}
\end{array}
Initial program 76.4%
associate-*l/76.6%
fma-def76.6%
associate-*r*76.6%
fma-udef76.6%
Applied egg-rr76.5%
Taylor expanded in w around 0 76.5%
unpow276.6%
unpow276.6%
swap-sqr76.6%
unpow276.6%
unpow276.6%
unpow276.6%
swap-sqr76.6%
unpow276.6%
unpow276.6%
unpow276.6%
swap-sqr76.6%
unpow276.6%
*-commutative76.6%
*-commutative76.6%
unpow276.6%
unpow276.6%
Simplified76.5%
Taylor expanded in w around 0 76.4%
*-commutative76.5%
unpow276.5%
unpow276.5%
swap-sqr76.5%
unpow276.5%
*-commutative76.5%
unpow276.5%
unpow276.5%
swap-sqr76.5%
unpow276.5%
*-commutative76.5%
unpow276.5%
unpow276.5%
swap-sqr76.6%
*-commutative76.6%
Simplified76.5%
Applied egg-rr76.6%
Final simplification76.6%
herbie shell --seed 2023292
(FPCore (w h dX.u dX.v dY.u dY.v maxAniso)
:name "Anisotropic x16 LOD (line direction, v)"
:precision binary32
:pre (and (and (and (and (and (and (and (<= 1.0 w) (<= w 16384.0)) (and (<= 1.0 h) (<= h 16384.0))) (and (<= 1e-20 (fabs dX.u)) (<= (fabs dX.u) 1e+20))) (and (<= 1e-20 (fabs dX.v)) (<= (fabs dX.v) 1e+20))) (and (<= 1e-20 (fabs dY.u)) (<= (fabs dY.u) 1e+20))) (and (<= 1e-20 (fabs dY.v)) (<= (fabs dY.v) 1e+20))) (== maxAniso 16.0))
(if (>= (+ (* (* (floor w) dX.u) (* (floor w) dX.u)) (* (* (floor h) dX.v) (* (floor h) dX.v))) (+ (* (* (floor w) dY.u) (* (floor w) dY.u)) (* (* (floor h) dY.v) (* (floor h) dY.v)))) (* (/ 1.0 (sqrt (fmax (+ (* (* (floor w) dX.u) (* (floor w) dX.u)) (* (* (floor h) dX.v) (* (floor h) dX.v))) (+ (* (* (floor w) dY.u) (* (floor w) dY.u)) (* (* (floor h) dY.v) (* (floor h) dY.v)))))) (* (floor h) dX.v)) (* (/ 1.0 (sqrt (fmax (+ (* (* (floor w) dX.u) (* (floor w) dX.u)) (* (* (floor h) dX.v) (* (floor h) dX.v))) (+ (* (* (floor w) dY.u) (* (floor w) dY.u)) (* (* (floor h) dY.v) (* (floor h) dY.v)))))) (* (floor h) dY.v))))