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Difference between revisions of "User:Boris Tsirelson/sandbox2"

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(Undo revision 35590 by Boris Tsirelson (talk))
 
(12 intermediate revisions by the same user not shown)
Line 12: Line 12:
  
 
I guess, the reason is that there Asy generates pdf file (converted into png afterwards), and here something else (probably ps).
 
I guess, the reason is that there Asy generates pdf file (converted into png afterwards), and here something else (probably ps).
 +
 +
No, it seems, it generates eps, both here and there. Then, what could be the reason?
  
 
More.
 
More.
Line 31: Line 33:
  
 
Mysterious.
 
Mysterious.
 +
 +
==Three dimensions==
 +
 +
<center><asy>
 +
settings.render = 0;
 +
 +
unitsize(100);
 +
 +
import three;
 +
import tube;
 +
 +
import graph;
 +
path unitCircle = Circle((0,0),1,35);
 +
 +
currentprojection = perspective((900,-350,-650));
 +
currentlight=light(gray(0.4),specularfactor=3,viewport=false,(-0.5,-0.5,-0.75),(0,-0.5,0.5),(0.5,0.5,0.75));
 +
// currentlight=light(gray(0.4),specularfactor=3,viewport=false,(-0.5,-0.5,-0.75),(0.5,-0.5,0.5),(0.5,0.5,0.75));
 +
 +
triple horn_start=(0,-1,0.6);
 +
triple horn_end=(0,0.4,0.2);
 +
real horn_radius=0.2;
 +
 +
real ratio=horn_end.z/(-horn_start.y);    // fractal levels ratio
 +
 +
transform3 implode_right = shift(horn_end) * scale3(ratio) * rotate(-90,X) * shift(-horn_start.y*Y);
 +
transform3 left_right = reflect(O,X,Z)*rotate(90,Y);
 +
 +
path[] cover_with_holes = scale(horn_radius/ratio)*unitCircle^^
 +
  shift((horn_start.z,0))*scale(0.9horn_radius)*reverse(unitCircle)^^
 +
  shift((-horn_start.z,0))*scale(0.9horn_radius)*reverse(unitCircle);
 +
surface cover = surface(cover_with_holes,ZXplane);
 +
surface cover_left = shift((horn_start.x,horn_start.y,0))*cover;
 +
surface two_covers = surface(cover_left,left_right*cover_left);
 +
 +
path3 horn_axis = horn_start..horn_start+(0,0.01,0)..(0,0,0.7)..(0,0.2,0.6)..horn_end+(0,0,0.01)..horn_end;
 +
 +
surface horn = tube( horn_axis, scale(horn_radius)*unitCircle );
 +
surface two_horns = surface(horn,reflect(O,X,Y)*horn);
 +
surface two_horns = surface(horn,reflect(O,X,Y)*horn);
 +
surface four_horns = surface(two_horns,left_right*two_horns,two_covers);
 +
 +
surface four_small_horns = implode_right*four_horns;
 +
surface eight_small_horns = surface(four_small_horns,left_right*four_small_horns);
 +
 +
surface big_surface = surface(four_horns,eight_small_horns);
 +
 +
real R = horn_radius/ratio;
 +
 +
draw ( circle((0,1,0), 1.005R, Y ), currentpen+2 );
 +
draw ( circle((horn_start.z,1.01,horn_start.x), horn_radius, Y ), currentpen+2 );
 +
draw ( circle((-horn_start.z,1.01,horn_start.x), horn_radius, Y ), currentpen+2 );
 +
 +
draw (big_surface, yellow);
 +
 +
pen blackpen = currentpen+1.5;
 +
 +
draw ( circle((0,-1,0), 1.005R, Y ), blackpen );
 +
draw ( circle(horn_start, 0.98horn_radius, Y ), blackpen );
 +
draw ( circle((horn_start.x,horn_start.y,-horn_start.z), 0.98horn_radius, Y ), blackpen );
 +
 +
real phi=0.9;  // adjust to the projection
 +
triple u = (cos(phi),0,sin(phi));
 +
draw( R*u-Y -- R*u+Y, blackpen );
 +
draw( -R*u-Y -- -R*u+Y, blackpen );
 +
 +
</asy></center>
 +
 +
 +
<center><asy>
 +
settings.render = 0;
 +
 +
size(200);
 +
import graph3;
 +
 +
currentprojection=perspective((2,2,5));
 +
 +
real R=1;
 +
real a=1;
 +
 +
real co=0.6;
 +
real colo=0.3;
 +
 +
triple f(pair t) {
 +
  return ((R+a*cos(t.y))*cos(t.x),(R+a*cos(t.y))*sin(t.x),a*sin(t.y));
 +
}
 +
 +
surface s=surface(f,(0,0),(2pi,2pi),20,20,Spline);
 +
 +
draw(s,rgb(co,co,co),meshpen=rgb(colo,colo,colo));
 +
 +
</asy></center>
 +
 +
==Sinusoid==
 +
 +
<center><asy>
 +
import graph;
 +
size(450);
 +
real f(real x) {return sin(x);};
 +
 +
real f1(real x) {return cos(x);};
 +
draw(graph(f1,-2*pi,2*pi),blue+1,"$\cos(x)$");
 +
draw(graph(f,-2*pi,2*pi),red+1,"$\sin(x)$");
 +
xaxis("$x$",Arrow);
 +
yaxis();
 +
 +
xtick("$\frac{\pi}{6}$",pi/6,N);
 +
xtick("$\frac{\pi}{4}$",pi/4,N);
 +
xtick("$\frac{\pi}{3}$",pi/3,N);
 +
xtick("$\frac{\pi}{2}$",pi/2,N);
 +
xtick("$\frac{3\pi}{2}$",3*pi/2,N);
 +
xtick("$\pi$",pi,N);
 +
xtick("$2\pi$",2*pi,N);
 +
xtick("$-\frac{\pi}{2}$",-pi/2,N);
 +
xtick("$-\frac{3\pi}{2}$",-3*pi/2,N);
 +
xtick("$-\pi$",-pi,N);
 +
xtick("$-2\pi$",-2*pi,N);
 +
 +
ytick("$1/2$",0.5,1,fontsize(8pt));
 +
ytick("$\sqrt{2}/2$",sqrt(2)/2,1,fontsize(8pt));
 +
ytick("$\sqrt{3}/2$",sqrt(3)/2,1,fontsize(8pt));
 +
ytick("$1$",1,1,fontsize(8pt));
 +
ytick("$-1/2$",-0.5,-1,fontsize(8pt));
 +
ytick("$-\sqrt{2}/2$",-sqrt(2)/2,-1,fontsize(8pt));
 +
ytick("$-\sqrt{3}/2$",-sqrt(3)/2,-1,fontsize(8pt));
 +
ytick("$-1$",-1,-1,fontsize(8pt));
 +
 +
attach(legend(),truepoint(E),10E,UnFill);
 +
</asy></center>
 +
 +
==Sinusoidal spiral==
 +
 +
<center><asy>
 +
import graph;
 +
size (200);
 +
 +
real r = 2.3;
 +
real m = 4;
 +
 +
real eps=10.^(-10);
 +
for  (int k=0; k<m; ++k) {
 +
  draw ( polargraph(  new real(real x) {return cos(m*x)^(1/m);}, -(pi/2m)+eps+k*2pi/m, (pi/2m)-eps+k*2pi/m ),
 +
defaultpen+1.5 );
 +
  draw ( -r*expi(-pi/2m+k*2pi/m)..r*expi(-pi/2m+k*2pi/m), dashed );
 +
  draw ( -r*expi(pi/2m+k*2pi/m)..r*expi(pi/2m+k*2pi/m), dashed );
 +
}
 +
label( "$m=4$", (0.58,0.02), fontsize(7pt) );
 +
 +
real eps=10.^(-2);
 +
for  (int k=0; k<m; ++k) {
 +
  draw ( polargraph(  new real(real x) {return cos(m*x)^(-1/m);}, -(pi/2m)+eps+k*2pi/m, (pi/2m)-eps+k*2pi/m ),
 +
defaultpen+1.5 );
 +
}
 +
label( "$m=-4$", (1.55,0.02), fontsize(7pt) );
 +
 +
label( "sinusoidal spiral: $a=1$", (0,2.3) );
 +
draw ( unitcircle, dashed );
 +
</asy></center>
  
 
==Power function==
 
==Power function==
Line 38: Line 197:
 
picture whole;
 
picture whole;
  
−
real sc=0.7;
+
real sc=0.8;
  
 
draw ( graph( new real(real x) {return x;}, -2, 2), red+1.2, "$y=x$" );
 
draw ( graph( new real(real x) {return x;}, -2, 2), red+1.2, "$y=x$" );
Line 54: Line 213:
 
draw( scale(mrg)*box((-2,-2),(2,2)), white );
 
draw( scale(mrg)*box((-2,-2),(2,2)), white );
  
−
add (whole,shift(-sc*220,0)*currentpicture.fit(sc*mrg*6.5cm));
+
add (whole,shift(-sc*230,0)*currentpicture.fit(sc*mrg*6.5cm));
 
erase();
 
erase();
  
Line 94: Line 253:
 
draw( scale(mrg)*box((-4,-4),(4,4)), white );
 
draw( scale(mrg)*box((-4,-4),(4,4)), white );
  
−
add (whole,shift(sc*220,0)*currentpicture.fit(sc*mrg*6.5cm,mrg*6.5cm,false));
+
add (whole,shift(sc*230,0)*currentpicture.fit(sc*mrg*6.5cm,mrg*6.5cm,false));
 
erase();
 
erase();
  

Latest revision as of 20:14, 12 December 2014

Experiments

Note a fine distinction from Ada:

I guess, the reason is that there Asy generates pdf file (converted into png afterwards), and here something else (probably ps).

No, it seems, it generates eps, both here and there. Then, what could be the reason?

More.


Mysterious.

Three dimensions


Sinusoid

Sinusoidal spiral

Power function

Kolmogorov test

Golden ratio

Strangely, the figure in EoM is erroneous! ED=EB, not BD=EB.





[Calculus: ] the art of numbering and measuring exactly a thing whose existence cannot be conceived. (Voltaire, Letter XVII: On Infinites In Geometry, And Sir Isaac Newton's Chronology)

And what are these fluxions? The velocities of evanescent increments? They are neither finite quantities, nor quantities infinitely small, nor yet nothing. May we not call them ghosts of departed quantities? (Berkeley, The Analyst)


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How to Cite This Entry:
Boris Tsirelson/sandbox2. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Boris_Tsirelson/sandbox2&oldid=35309
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