# File:Sinftes04t300.jpg

Explicit plot of the simplest self-SinFT function

$y=F(x)=2x \exp(-x^2/2)~$ , thin smooth curve,

its discrete representation at the mesh with 4 nodes (thick colored segmented line),

and its SFT (black segmented line). Even with so view nodes, visually, the two segmented curves practically coincide; the array is reproduced with at least 3 decimal digits.

## C++ generator of lines

// Files ado.cin and scft.cin should be loaded in order of compile the code below

#include <stdio.h>

#include <math.h>

#include<stdlib.h>

#include "scft.cin"

#include "ado.cin"

#define NP 4

int main(){ int i; double a[NP],b[NP]; double d=sqrt(M_PI/NP); double x,y; FILE *o;

for(i=0;i<NP;i++){ x=i*d; a[i]=b[i]=2.*x*exp(-.5*x*x); }

sinft(b-1,NP);

for(i=0;i<NP;i++) { b[i]*=sqrt(2./NP); printf("%2d %19.14lf %19.14lf %19.14lf\n",i,a[i],b[i], b[i]-a[i]);}

//o=fopen("34.eps","w"); ado(o,470,140);

o=fopen("sinftes04.eps","w"); ado(o,570,140);

#define M(x,y) fprintf(o,"%9.4lf %9.4lf M\n",x+0.,y+0.);

#define L(x,y) fprintf(o,"%9.4lf %9.4lf L\n",x+0.,y+0.);

fprintf(o,"10 10 translate 100 100 scale 2 setlinecap 1 setlinejoin\n");

for(i=0;i<12;i++){M(.5*i,0)L(.5*i,1)}

for(i=0;i<3;i++){M(0,.5*i)L(5.5,.5*i)}

fprintf(o,".007 W S\n");

M(0,0); for(i=1;i<110;i++) { x=.05*i; y=2.*x*exp(-.5*x*x); L(x,y);} fprintf(o,".009 W 0 0 0 RGB S\n");

M(0,0); for(i=1;i<NP;i++) { x=d*i; y=a[i]; L(x,y);} fprintf(o,".04 W 1 0 .5 RGB S\n");

M(0,0); for(i=1;i<NP;i++) { x=d*i; y=b[i]; L(x,y);} fprintf(o,".015 W 0 0 0 RGB S\n");

fprintf(o,"showpage\n%c%cTrailer\n",'%','%');

fclose(o);

system("epstopdf sinftes04.eps");

system( "open sinftes04.pdf");

}

## Latex generator of curve

## References

## File history

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Date/Time | Thumbnail | Dimensions | User | Comment | |
---|---|---|---|---|---|

current | 06:14, 1 December 2018 | 1,183 × 282 (48 KB) | Maintenance script (talk | contribs) | Importing image file |

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## File usage

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