Why is this recursive code so slow? The 2019 Stack Overflow Developer Survey Results Are In ...

Wall plug outlet change

Mortgage adviser recommends a longer term than necessary combined with overpayments

How did passengers keep warm on sail ships?

Would an alien lifeform be able to achieve space travel if lacking in vision?

How long does the line of fire that you can create as an action using the Investiture of Flame spell last?

Why can't devices on different VLANs, but on the same subnet, communicate?

What LEGO pieces have "real-world" functionality?

Why is superheterodyning better than direct conversion?

How do you keep chess fun when your opponent constantly beats you?

Keeping a retro style to sci-fi spaceships?

What force causes entropy to increase?

Can a novice safely splice in wire to lengthen 5V charging cable?

Hiding Certain Lines on Table

Semisimplicity of the category of coherent sheaves?

Is it ok to offer lower paid work as a trial period before negotiating for a full-time job?

How are presidential pardons supposed to be used?

Road tyres vs "Street" tyres for charity ride on MTB Tandem

Does Parliament need to approve the new Brexit delay to 31 October 2019?

Why can't wing-mounted spoilers be used to steepen approaches?

How to delete random line from file using Unix command?

I could not break this equation. Please help me

In horse breeding, what is the female equivalent of putting a horse out "to stud"?

Typeface like Times New Roman but with "tied" percent sign

How to stretch delimiters to envolve matrices inside of a kbordermatrix?



Why is this recursive code so slow?



The 2019 Stack Overflow Developer Survey Results Are In
Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)What are the hidden specifications for FindRootWhy does this function inside FindRoot fail to evaluate?Very slow mathematica finite differencesUsing Mathematica to solve a recursive system of differential equationsImproving the speed on an iterated differential systemForward iterations of coupled recursion equationsManipulate+FindRoot+Plot3D very slow/crashAttacking a “Mathematica can't solve” problemErrors using FindRoot on slow numerical functionAvoiding a for loop to create a list












5












$begingroup$


This code for the first five iterations the speed is okay, but after that the speed is very slow, I cannot understand what is wrong with this? Would you please help me fix it?



Clear[A, r, x, s, e]
s := 0.3405
e := 1.6539*10^-21
u[0] := 0.
u[1] := 0.1

A[r_] := A[r] =
Piecewise[{{r - 2.5 s - 48*e *s^12*r^-13 + 24*e*s^6*r^-7,
r > 2.5 s}, {-48*e*s^12*r^-13 + 24*e*s^6*r^-7,
s <= r <= 2.5 s}, {r - s -
24*e*s^-1, r < s}}]
For[i = 2, i < 101,
i++, { u[i_] :=
x /. FindRoot[
u[i - 1] +
1/(i^2 (u[i - 1] - u[i - 2])^2) (u[i - 1] - u[i - 2]) -
0.9 A[x] == x , {x, 1.}]; Print[u[i]]}]









share|improve this question











$endgroup$












  • $begingroup$
    How slow? How many minutes/seconds?
    $endgroup$
    – JonyD
    yesterday
















5












$begingroup$


This code for the first five iterations the speed is okay, but after that the speed is very slow, I cannot understand what is wrong with this? Would you please help me fix it?



Clear[A, r, x, s, e]
s := 0.3405
e := 1.6539*10^-21
u[0] := 0.
u[1] := 0.1

A[r_] := A[r] =
Piecewise[{{r - 2.5 s - 48*e *s^12*r^-13 + 24*e*s^6*r^-7,
r > 2.5 s}, {-48*e*s^12*r^-13 + 24*e*s^6*r^-7,
s <= r <= 2.5 s}, {r - s -
24*e*s^-1, r < s}}]
For[i = 2, i < 101,
i++, { u[i_] :=
x /. FindRoot[
u[i - 1] +
1/(i^2 (u[i - 1] - u[i - 2])^2) (u[i - 1] - u[i - 2]) -
0.9 A[x] == x , {x, 1.}]; Print[u[i]]}]









share|improve this question











$endgroup$












  • $begingroup$
    How slow? How many minutes/seconds?
    $endgroup$
    – JonyD
    yesterday














5












5








5





$begingroup$


This code for the first five iterations the speed is okay, but after that the speed is very slow, I cannot understand what is wrong with this? Would you please help me fix it?



Clear[A, r, x, s, e]
s := 0.3405
e := 1.6539*10^-21
u[0] := 0.
u[1] := 0.1

A[r_] := A[r] =
Piecewise[{{r - 2.5 s - 48*e *s^12*r^-13 + 24*e*s^6*r^-7,
r > 2.5 s}, {-48*e*s^12*r^-13 + 24*e*s^6*r^-7,
s <= r <= 2.5 s}, {r - s -
24*e*s^-1, r < s}}]
For[i = 2, i < 101,
i++, { u[i_] :=
x /. FindRoot[
u[i - 1] +
1/(i^2 (u[i - 1] - u[i - 2])^2) (u[i - 1] - u[i - 2]) -
0.9 A[x] == x , {x, 1.}]; Print[u[i]]}]









share|improve this question











$endgroup$




This code for the first five iterations the speed is okay, but after that the speed is very slow, I cannot understand what is wrong with this? Would you please help me fix it?



Clear[A, r, x, s, e]
s := 0.3405
e := 1.6539*10^-21
u[0] := 0.
u[1] := 0.1

A[r_] := A[r] =
Piecewise[{{r - 2.5 s - 48*e *s^12*r^-13 + 24*e*s^6*r^-7,
r > 2.5 s}, {-48*e*s^12*r^-13 + 24*e*s^6*r^-7,
s <= r <= 2.5 s}, {r - s -
24*e*s^-1, r < s}}]
For[i = 2, i < 101,
i++, { u[i_] :=
x /. FindRoot[
u[i - 1] +
1/(i^2 (u[i - 1] - u[i - 2])^2) (u[i - 1] - u[i - 2]) -
0.9 A[x] == x , {x, 1.}]; Print[u[i]]}]






equation-solving recursion






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited yesterday









Roman

5,24511131




5,24511131










asked 2 days ago









morapimorapi

355




355












  • $begingroup$
    How slow? How many minutes/seconds?
    $endgroup$
    – JonyD
    yesterday


















  • $begingroup$
    How slow? How many minutes/seconds?
    $endgroup$
    – JonyD
    yesterday
















$begingroup$
How slow? How many minutes/seconds?
$endgroup$
– JonyD
yesterday




$begingroup$
How slow? How many minutes/seconds?
$endgroup$
– JonyD
yesterday










1 Answer
1






active

oldest

votes


















12












$begingroup$

I recommend you learn the distinction between immediate (=) and delayed (:=) assignments. They make the difference between slow and fast code here. Start with this tutorial or this book chapter, then look at memoization.



s = 0.3405;
e = 1.6539*10^-21;
u[0] = 0.;
u[1] = 0.1;

A[r_] = Piecewise[{{r - 2.5 s - 48*e*s^12*r^-13 + 24*e*s^6*r^-7, r > 2.5 s},
{-48*e*s^12*r^-13 + 24*e*s^6*r^-7, s <= r <= 2.5 s},
{r - s - 24*e*s^-1, r < s}}];

u[i_] := u[i] = x /. FindRoot[
u[i - 1] + 1/(i^2 (u[i - 1] - u[i - 2])^2) (u[i - 1] - u[i - 2]) - 0.9 A[x] == x, {x, 1.}]

Array[u, 100]



{0.1, 1.77164, 1.37065, 1.04259, 0.887781, 0.708344, 0.59461,
0.457228, 0.367364, 0.296071, 0.256104, 0.20463, 0.208487, 1.20917,
1.04197, 0.939331, 0.879865, 0.827963, 0.774591, 0.72775, 0.67934,
0.63666, 0.592369, 0.553172, 0.512352, 0.476112, 0.438261, 0.404563,
0.369277, 0.339073, 0.321616, 0.301118, 0.296195, 0.224688, 0.273538,
0.31357, 0.33593, 0.366902, 0.38813, 0.417572, 0.437777, 0.465834,
0.48511, 0.511907, 0.530336, 0.55598, 0.573633, 0.598219, 0.615159,
0.638772, 0.655054, 0.677768, 0.693441, 0.715321, 0.73043, 0.751535,
0.766118, 0.786503, 0.800596, 0.820306, 0.833941, 0.852182, 0.85901,
0.874152, 0.871531, 0.78396, 0.781416, 0.696402, 0.693931, 0.611329,
0.608927, 0.528603, 0.526267, 0.448099, 0.445825, 0.369701, 0.367485,
0.315658, 0.325798, 0.341207, 0.351098, 0.366134, 0.375788, 0.390468,
0.399897, 0.414237, 0.42345, 0.437466, 0.446473, 0.46018, 0.46899,
0.4824, 0.491022, 0.504149, 0.51259, 0.525444, 0.533712, 0.546306,
0.554408, 0.56675}




(takes about 1.3 seconds)



Alternatively, use



Table[u[i], {i, 1, 100}]


(same result). Your combination of For and Print shows the results but doesn't let you keep using them for more calculations.






share|improve this answer











$endgroup$













  • $begingroup$
    thank you very much. I really appreciate it.
    $endgroup$
    – morapi
    yesterday










  • $begingroup$
    delayed assignments definitely sound slower than immediate, even if I have never worked with Mathematica
    $endgroup$
    – Roland
    yesterday








  • 2




    $begingroup$
    @Roland it's not just that one is necessarily faster or slower than the other, it's more that they are completely different things with very different applications. For some reason this point is often overlooked by beginners in Mathematica.
    $endgroup$
    – Roman
    yesterday












Your Answer








StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "387"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathematica.stackexchange.com%2fquestions%2f195054%2fwhy-is-this-recursive-code-so-slow%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









12












$begingroup$

I recommend you learn the distinction between immediate (=) and delayed (:=) assignments. They make the difference between slow and fast code here. Start with this tutorial or this book chapter, then look at memoization.



s = 0.3405;
e = 1.6539*10^-21;
u[0] = 0.;
u[1] = 0.1;

A[r_] = Piecewise[{{r - 2.5 s - 48*e*s^12*r^-13 + 24*e*s^6*r^-7, r > 2.5 s},
{-48*e*s^12*r^-13 + 24*e*s^6*r^-7, s <= r <= 2.5 s},
{r - s - 24*e*s^-1, r < s}}];

u[i_] := u[i] = x /. FindRoot[
u[i - 1] + 1/(i^2 (u[i - 1] - u[i - 2])^2) (u[i - 1] - u[i - 2]) - 0.9 A[x] == x, {x, 1.}]

Array[u, 100]



{0.1, 1.77164, 1.37065, 1.04259, 0.887781, 0.708344, 0.59461,
0.457228, 0.367364, 0.296071, 0.256104, 0.20463, 0.208487, 1.20917,
1.04197, 0.939331, 0.879865, 0.827963, 0.774591, 0.72775, 0.67934,
0.63666, 0.592369, 0.553172, 0.512352, 0.476112, 0.438261, 0.404563,
0.369277, 0.339073, 0.321616, 0.301118, 0.296195, 0.224688, 0.273538,
0.31357, 0.33593, 0.366902, 0.38813, 0.417572, 0.437777, 0.465834,
0.48511, 0.511907, 0.530336, 0.55598, 0.573633, 0.598219, 0.615159,
0.638772, 0.655054, 0.677768, 0.693441, 0.715321, 0.73043, 0.751535,
0.766118, 0.786503, 0.800596, 0.820306, 0.833941, 0.852182, 0.85901,
0.874152, 0.871531, 0.78396, 0.781416, 0.696402, 0.693931, 0.611329,
0.608927, 0.528603, 0.526267, 0.448099, 0.445825, 0.369701, 0.367485,
0.315658, 0.325798, 0.341207, 0.351098, 0.366134, 0.375788, 0.390468,
0.399897, 0.414237, 0.42345, 0.437466, 0.446473, 0.46018, 0.46899,
0.4824, 0.491022, 0.504149, 0.51259, 0.525444, 0.533712, 0.546306,
0.554408, 0.56675}




(takes about 1.3 seconds)



Alternatively, use



Table[u[i], {i, 1, 100}]


(same result). Your combination of For and Print shows the results but doesn't let you keep using them for more calculations.






share|improve this answer











$endgroup$













  • $begingroup$
    thank you very much. I really appreciate it.
    $endgroup$
    – morapi
    yesterday










  • $begingroup$
    delayed assignments definitely sound slower than immediate, even if I have never worked with Mathematica
    $endgroup$
    – Roland
    yesterday








  • 2




    $begingroup$
    @Roland it's not just that one is necessarily faster or slower than the other, it's more that they are completely different things with very different applications. For some reason this point is often overlooked by beginners in Mathematica.
    $endgroup$
    – Roman
    yesterday
















12












$begingroup$

I recommend you learn the distinction between immediate (=) and delayed (:=) assignments. They make the difference between slow and fast code here. Start with this tutorial or this book chapter, then look at memoization.



s = 0.3405;
e = 1.6539*10^-21;
u[0] = 0.;
u[1] = 0.1;

A[r_] = Piecewise[{{r - 2.5 s - 48*e*s^12*r^-13 + 24*e*s^6*r^-7, r > 2.5 s},
{-48*e*s^12*r^-13 + 24*e*s^6*r^-7, s <= r <= 2.5 s},
{r - s - 24*e*s^-1, r < s}}];

u[i_] := u[i] = x /. FindRoot[
u[i - 1] + 1/(i^2 (u[i - 1] - u[i - 2])^2) (u[i - 1] - u[i - 2]) - 0.9 A[x] == x, {x, 1.}]

Array[u, 100]



{0.1, 1.77164, 1.37065, 1.04259, 0.887781, 0.708344, 0.59461,
0.457228, 0.367364, 0.296071, 0.256104, 0.20463, 0.208487, 1.20917,
1.04197, 0.939331, 0.879865, 0.827963, 0.774591, 0.72775, 0.67934,
0.63666, 0.592369, 0.553172, 0.512352, 0.476112, 0.438261, 0.404563,
0.369277, 0.339073, 0.321616, 0.301118, 0.296195, 0.224688, 0.273538,
0.31357, 0.33593, 0.366902, 0.38813, 0.417572, 0.437777, 0.465834,
0.48511, 0.511907, 0.530336, 0.55598, 0.573633, 0.598219, 0.615159,
0.638772, 0.655054, 0.677768, 0.693441, 0.715321, 0.73043, 0.751535,
0.766118, 0.786503, 0.800596, 0.820306, 0.833941, 0.852182, 0.85901,
0.874152, 0.871531, 0.78396, 0.781416, 0.696402, 0.693931, 0.611329,
0.608927, 0.528603, 0.526267, 0.448099, 0.445825, 0.369701, 0.367485,
0.315658, 0.325798, 0.341207, 0.351098, 0.366134, 0.375788, 0.390468,
0.399897, 0.414237, 0.42345, 0.437466, 0.446473, 0.46018, 0.46899,
0.4824, 0.491022, 0.504149, 0.51259, 0.525444, 0.533712, 0.546306,
0.554408, 0.56675}




(takes about 1.3 seconds)



Alternatively, use



Table[u[i], {i, 1, 100}]


(same result). Your combination of For and Print shows the results but doesn't let you keep using them for more calculations.






share|improve this answer











$endgroup$













  • $begingroup$
    thank you very much. I really appreciate it.
    $endgroup$
    – morapi
    yesterday










  • $begingroup$
    delayed assignments definitely sound slower than immediate, even if I have never worked with Mathematica
    $endgroup$
    – Roland
    yesterday








  • 2




    $begingroup$
    @Roland it's not just that one is necessarily faster or slower than the other, it's more that they are completely different things with very different applications. For some reason this point is often overlooked by beginners in Mathematica.
    $endgroup$
    – Roman
    yesterday














12












12








12





$begingroup$

I recommend you learn the distinction between immediate (=) and delayed (:=) assignments. They make the difference between slow and fast code here. Start with this tutorial or this book chapter, then look at memoization.



s = 0.3405;
e = 1.6539*10^-21;
u[0] = 0.;
u[1] = 0.1;

A[r_] = Piecewise[{{r - 2.5 s - 48*e*s^12*r^-13 + 24*e*s^6*r^-7, r > 2.5 s},
{-48*e*s^12*r^-13 + 24*e*s^6*r^-7, s <= r <= 2.5 s},
{r - s - 24*e*s^-1, r < s}}];

u[i_] := u[i] = x /. FindRoot[
u[i - 1] + 1/(i^2 (u[i - 1] - u[i - 2])^2) (u[i - 1] - u[i - 2]) - 0.9 A[x] == x, {x, 1.}]

Array[u, 100]



{0.1, 1.77164, 1.37065, 1.04259, 0.887781, 0.708344, 0.59461,
0.457228, 0.367364, 0.296071, 0.256104, 0.20463, 0.208487, 1.20917,
1.04197, 0.939331, 0.879865, 0.827963, 0.774591, 0.72775, 0.67934,
0.63666, 0.592369, 0.553172, 0.512352, 0.476112, 0.438261, 0.404563,
0.369277, 0.339073, 0.321616, 0.301118, 0.296195, 0.224688, 0.273538,
0.31357, 0.33593, 0.366902, 0.38813, 0.417572, 0.437777, 0.465834,
0.48511, 0.511907, 0.530336, 0.55598, 0.573633, 0.598219, 0.615159,
0.638772, 0.655054, 0.677768, 0.693441, 0.715321, 0.73043, 0.751535,
0.766118, 0.786503, 0.800596, 0.820306, 0.833941, 0.852182, 0.85901,
0.874152, 0.871531, 0.78396, 0.781416, 0.696402, 0.693931, 0.611329,
0.608927, 0.528603, 0.526267, 0.448099, 0.445825, 0.369701, 0.367485,
0.315658, 0.325798, 0.341207, 0.351098, 0.366134, 0.375788, 0.390468,
0.399897, 0.414237, 0.42345, 0.437466, 0.446473, 0.46018, 0.46899,
0.4824, 0.491022, 0.504149, 0.51259, 0.525444, 0.533712, 0.546306,
0.554408, 0.56675}




(takes about 1.3 seconds)



Alternatively, use



Table[u[i], {i, 1, 100}]


(same result). Your combination of For and Print shows the results but doesn't let you keep using them for more calculations.






share|improve this answer











$endgroup$



I recommend you learn the distinction between immediate (=) and delayed (:=) assignments. They make the difference between slow and fast code here. Start with this tutorial or this book chapter, then look at memoization.



s = 0.3405;
e = 1.6539*10^-21;
u[0] = 0.;
u[1] = 0.1;

A[r_] = Piecewise[{{r - 2.5 s - 48*e*s^12*r^-13 + 24*e*s^6*r^-7, r > 2.5 s},
{-48*e*s^12*r^-13 + 24*e*s^6*r^-7, s <= r <= 2.5 s},
{r - s - 24*e*s^-1, r < s}}];

u[i_] := u[i] = x /. FindRoot[
u[i - 1] + 1/(i^2 (u[i - 1] - u[i - 2])^2) (u[i - 1] - u[i - 2]) - 0.9 A[x] == x, {x, 1.}]

Array[u, 100]



{0.1, 1.77164, 1.37065, 1.04259, 0.887781, 0.708344, 0.59461,
0.457228, 0.367364, 0.296071, 0.256104, 0.20463, 0.208487, 1.20917,
1.04197, 0.939331, 0.879865, 0.827963, 0.774591, 0.72775, 0.67934,
0.63666, 0.592369, 0.553172, 0.512352, 0.476112, 0.438261, 0.404563,
0.369277, 0.339073, 0.321616, 0.301118, 0.296195, 0.224688, 0.273538,
0.31357, 0.33593, 0.366902, 0.38813, 0.417572, 0.437777, 0.465834,
0.48511, 0.511907, 0.530336, 0.55598, 0.573633, 0.598219, 0.615159,
0.638772, 0.655054, 0.677768, 0.693441, 0.715321, 0.73043, 0.751535,
0.766118, 0.786503, 0.800596, 0.820306, 0.833941, 0.852182, 0.85901,
0.874152, 0.871531, 0.78396, 0.781416, 0.696402, 0.693931, 0.611329,
0.608927, 0.528603, 0.526267, 0.448099, 0.445825, 0.369701, 0.367485,
0.315658, 0.325798, 0.341207, 0.351098, 0.366134, 0.375788, 0.390468,
0.399897, 0.414237, 0.42345, 0.437466, 0.446473, 0.46018, 0.46899,
0.4824, 0.491022, 0.504149, 0.51259, 0.525444, 0.533712, 0.546306,
0.554408, 0.56675}




(takes about 1.3 seconds)



Alternatively, use



Table[u[i], {i, 1, 100}]


(same result). Your combination of For and Print shows the results but doesn't let you keep using them for more calculations.







share|improve this answer














share|improve this answer



share|improve this answer








edited yesterday

























answered yesterday









RomanRoman

5,24511131




5,24511131












  • $begingroup$
    thank you very much. I really appreciate it.
    $endgroup$
    – morapi
    yesterday










  • $begingroup$
    delayed assignments definitely sound slower than immediate, even if I have never worked with Mathematica
    $endgroup$
    – Roland
    yesterday








  • 2




    $begingroup$
    @Roland it's not just that one is necessarily faster or slower than the other, it's more that they are completely different things with very different applications. For some reason this point is often overlooked by beginners in Mathematica.
    $endgroup$
    – Roman
    yesterday


















  • $begingroup$
    thank you very much. I really appreciate it.
    $endgroup$
    – morapi
    yesterday










  • $begingroup$
    delayed assignments definitely sound slower than immediate, even if I have never worked with Mathematica
    $endgroup$
    – Roland
    yesterday








  • 2




    $begingroup$
    @Roland it's not just that one is necessarily faster or slower than the other, it's more that they are completely different things with very different applications. For some reason this point is often overlooked by beginners in Mathematica.
    $endgroup$
    – Roman
    yesterday
















$begingroup$
thank you very much. I really appreciate it.
$endgroup$
– morapi
yesterday




$begingroup$
thank you very much. I really appreciate it.
$endgroup$
– morapi
yesterday












$begingroup$
delayed assignments definitely sound slower than immediate, even if I have never worked with Mathematica
$endgroup$
– Roland
yesterday






$begingroup$
delayed assignments definitely sound slower than immediate, even if I have never worked with Mathematica
$endgroup$
– Roland
yesterday






2




2




$begingroup$
@Roland it's not just that one is necessarily faster or slower than the other, it's more that they are completely different things with very different applications. For some reason this point is often overlooked by beginners in Mathematica.
$endgroup$
– Roman
yesterday




$begingroup$
@Roland it's not just that one is necessarily faster or slower than the other, it's more that they are completely different things with very different applications. For some reason this point is often overlooked by beginners in Mathematica.
$endgroup$
– Roman
yesterday


















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematica Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathematica.stackexchange.com%2fquestions%2f195054%2fwhy-is-this-recursive-code-so-slow%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

VNC viewer RFB protocol error: bad desktop size 0x0I Cannot Type the Key 'd' (lowercase) in VNC Viewer...

Couldn't open a raw socket. Error: Permission denied (13) (nmap)Is it possible to run networking commands...

Why not use the yoke to control yaw, as well as pitch and roll? Announcing the arrival of...