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# Contour plot/Code/conto.cin

< Contour plot‎ | Code
// one of functions required for generaiton of figure
//
// Copyleft 2008 by Dmitrii Kouznetsov
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#define DB double
#define DB double
#define DO(x,y) for(x=0;x<y;x++)
#define M(x,y) fprintf(o,"%5.3f %5.3f M\n",1.*(x),1.*(y));
#define L(x,y) fprintf(o,"%5.3f %5.3f L\n",1.*(x),1.*(y));
//#define o(x,y) fprintf(o,"%5.3f %5.3f o\n",1.*(x),1.*(y));
#define Mxy M(x,y)
#define Lxy L(x,y)
#define f(m,n) F[(m)*N1+(n)]
#define z(m,n) Z[(m)*N1+(n)]
#define zmn z(m,n)
#define zMn z(m+1,n)
#define zmN z(m,n+1)
#define zMN z(m+1,n+1)
#define fmn f(m,n)
#define fMn f(m+1,n)
#define fmN f(m,n+1)
#define fMN f(m+1,n+1)
#define Xm X[m]
#define XM X[m+1]
#define Yn Y[n]
#define YN Y[n+1]
#define bdpq {b=f(m,n+1);d=f(m+1,n+1);p=f(m,n);q=f(m+1,n);}
#define UPP 1
#define LEF 2
#define DOW 3
#define RIG 4

DB drift(FILE *o,DB *F,char *Z,DB *X,DB *Y,int M,int N,int m,int n,int K)
{int M1=M+1,N1=N+1; DB b,d, p,q, x,y, B,D,P,Q; int mO=m,nO=n;
//printf("drift: K=%2d, m=%2d n=%2d  \n",K,m,n);

if(K==UPP) goto Up;
if(K==LEF) goto Le;
if(K==DOW) goto Do;
if(K==RIG) goto Ri;

Up:if(zmn=='b'||zmn=='d'||zmn=='p'||zmn=='q'||zmn=='o'){return 0.;}
if(zmn=='|'||zmn=='+'||zmn=='/'||zmn=='L'){if(m==mO&&n==nO)fprintf(o,"C\n");return 0.;}
bdpq;
//printf("Up: m=%2d n=%2d bdpq=%5.2f %5.2f %5.2f %5.2f\n",m,n,b,d,p,q); //getchar();
if(b*d<0){x=Xm+(XM-Xm)*b/(b-d);y=YN;Lxy;if(zmn=='-')zmn='+';else zmn='|';n++;
if(n>=N) return 0.; goto Up;}
if(q*d<0){y=Yn+(YN-Yn)*q/(q-d);x=XM;Lxy;zmn='/';m++;if(m>=M)return 0; goto Ri;}
if(b*p<0){y=Yn+(YN-Yn)*p/(p-b);x=Xm;Lxy;zmn='L';m--;if(m<0)return 0; goto Le;}
//printf("handle zero, m=%2d n=%2d\n", m,n);
if(d*d==0){ zmn='o';m++;n++;L(X[m],Y[n]); //printf("Go to UR");
goto UR;}
if(b*b==0){zmn='o';n++; L(X[m],Y[n]);m--; goto UL;}
//end Up

Le:if(zmn=='b'||zmn=='d'||zmn=='p'||zmn=='q'||zmn=='o'){return 0.;}
if(zmn=='-'||zmn=='+'||zmn=='/'||zmn=='L'){if(m==mO&&n==nO)fprintf(o,"C\n");return 0.;}
bdpq;
//printf("Le: m=%2d n=%2d bdpq=%5.2f %5.2f %5.2f %5.2f\n",m,n,b,d,p,q);
if(b*p<0){y=Yn+(YN-Yn)*p/(p-b);x=Xm;Lxy;if(zmn=='|') zmn='+';
else zmn='-';m--;if(m<0)return 0; goto Le;}
if(p*q<0){x=Xm+(XM-Xm)*p/(p-q);y=Yn;Lxy;zmn='/';n--;if(n<0)return 0; goto Do;}
if(b*d<0){x=Xm+(XM-Xm)*b/(b-d);y=YN;Lxy;zmn='L';n++;if(n>=N)return 0; goto Up;}
//printf("Le Handles zero\n");
if(p*p==0){zmn='o';L(Xm,Yn);m--;n--;if(m<0||n<0) return 0;// printf("go to LD\n");
goto LD;}
if(b*b==0){zmn='o';n++;L(Xm,Yn);m--;if(m<0||n>=N)return 0;// printf("go to LU\n");
goto LU;}
//end Le

Do://come to cell m,n from the up and expect to go down.
if(zmn=='b'||zmn=='d'||zmn=='p'||zmn=='q'||zmn=='o') return 0.;
if(zmn=='|'||zmn=='+'||zmn=='/'||zmn=='L'){if(m==mO&&n==nO)fprintf(o,"C\n");return 0.;}
bdpq; //printf("Do: m=%2d n=%2d bdpq=%5.2f %5.2f %5.2f %5.2f\n",m,n,b,d,p,q);
if(p*q<0){x=Xm+(XM-Xm)*p/(p-q);y=Yn;Lxy;if(zmn=='-')zmn='+';
else zmn='|';n--;if(n<0)return 0; goto Do;}
if(b*p<0){y=Yn+(YN-Yn)*p/(p-b);x=Xm;Lxy;zmn='/';m--;if(m<0) return 0; goto Le;}
if(q*d<0){y=Yn+(YN-Yn)*q/(q-d);x=XM;Lxy;zmn='L';m++;if(m>=M) return 0; goto Ri;}
//printf("handle zero\n");
if(p*p==0){zmn='o';L(Xm,Yn);m--;n--; goto DL;}
if(q*q==0){zmn='o';m++;L(Xm,Yn);n--; goto DR;}
//end Do

Ri: //expect to go right..
if(zmn=='b'||zmn=='d'||zmn=='p'||zmn=='q'||zmn=='o')return 0.;
if(zmn=='-'||zmn=='+'||zmn=='/'||zmn=='L'){if(m==mO&&n==nO)fprintf(o,"C\n");return 0.;}
bdpq;//printf("Ri: m=%2d n=%2d bdpq=%5.2f %5.2f %5.2f %5.2f\n",m,n,b,d,p,q);
if(d*q<0){y=Yn+(YN-Yn)*q/(q-d);x=XM;Lxy;if(zmn=='-') zmn='+';


else zmn='|';m++;if(m>=M)return 0; goto Ri;}

if(b*d<0){x=Xm+(XM-Xm)*b/(b-d);y=YN;Lxy;zmn='/';n++;if(n>=N) return 0; goto Up;}
if(p*q<0){x=Xm+(XM-Xm)*p/(p-q);y=Yn;Lxy;zmn='L';n--;if(n<0)return 0; goto Do;}
//printf("handle zero\n");
if(d*d==0){zmn='o';m++;n++;L(Xm,Yn); goto UR;}
if(q*q==0){zmn='o';m++;L(Xm,Yn);n--; goto DR;}
//if(n<0 ||m>=M) return 0; goto Ri;}
return 0;
//end Ri

DL:
LD: //printf("LD m=%2d n=%2d (may be negative)\n",m,n);
//came to the cell (m,n) from upper right corner.
//This cell may exist at the mesh; check this option first.
if(m<0&&n<0) return 0; //corner of the mesh;
if(m<0){m++;bdpq;if(p*q<=0 && zmn==' ') goto Do; return 0;}
if(n<0){n++;bdpq;if(b*p<=0 && zmn==' ') goto Le; return 0;}
bdpq; // pri("inside. bdpq=%5.2f %5.2f %5.2f %5.2f\n", b,d,p,q);
if(p*q<=0 && zmn==' ') goto Do;
if(b*p<=0 && zmn==' ') goto Le;
Q=f(m+2,n); //pri("Q=%5.2f\n",Q);
if(Q*q<=0){m++;
if(zmn==' ')
{//printf("go to Do, m=%2d n=%2d\n",m,n);
goto Do;} return 0;}
B=f(m,n+2); if(B*b<=0){n++; if(zmn==' ') goto Le; return 0;}
return 0;

LU:UL:
//printf("UL: m=%2d n=%2d ( may be out of mesh)\n",m,n); //come from right down.
if(m<0&&n>=N) return 0; //corner of the mesh;
if(m<0){m++;bdpq;if(b*d<=0 && zmn==' ') goto Up; return 0;}
if(n>=N){n--;bdpq;if(b*p<=0 && zmn==' ') goto Le; return 0;}
bdpq; //pri("inside. bdpq=%5.2f %5.2f %5.2f %5.2f\n", b,d,p,q);
if(b*p<=0 && zmn==' ') goto Le;
if(b*d<=0 && zmn==' ') goto Up;
D=f(m+2,n+1); //pri("D=%5.2f\n",D);
if(D*d<=0){m++;if(zmn==' ') goto Up;}
//Q=f(m-1,n+1); //pr("Q=%5.2f\n",Q);
if(Q*q<=0){m--;if(zmn==' ') goto Le;}
P=f(m,n-1); //pri("P=%5.2f\n",P);
if(P*p<=0){n--;if(zmn==' ') goto Le;}
//if(p*p==0){L(X[m],Y[n]) zmn='-'; Z[m*N1+n-1]='-'; m--;n--; goto LD;}
return 0;

RU:
UR: //printf("UR: m=%2d n=%2d\n",m,n); //come from left down. May be out of mesh.
if(m>=M&&n>=N) return 0; //corner of the mesh;
if(m>=M){m--;bdpq;if(b*d<=0 && zmn==' ') goto Up; return 0;}
if(n>=N){n--;bdpq;if(d*q<=0 && zmn==' ') goto Ri; return 0;}
bdpq; //pri("inside. bdpq=%5.2f %5.2f %5.2f %5.2f\n", b,d,p,q);
if(d*q<=0 && zmn==' ') goto Ri;
if(b*d<=0 && zmn==' ') goto Up;
B=f(m-1,n+1); //pri("Q=%5.2f\n",Q);
if(B*b<=0){m--; if(zmn==' ') goto Up; return 0;}
Q=f(m+1,n-1); //pri("D=%5.2f\n",D);
if(Q*q<=0){n--; if(zmn==' ') goto Ri; return 0;}
return 0;

DR: RD: //printf("RD: m=%3d n=%2d\n",m,n);
if(m>=M&&n<0) return 0; //corner of the mesh;
if(m>=M){m--;bdpq;if(p*q<=0 && zmn==' ') goto Do; return 0;}
if(n<0 ){n++;bdpq;if(b*p<=0 && zmn==' ') goto Ri; return 0;}
bdpq; //pri("inside. bdpq=%5.2f %5.2f %5.2f %5.2f\n", b,d,p,q);
if(p*q<=0 && zmn==' ') goto Do;
if(d*q<=0 && zmn==' ') goto Ri;
Q=f(m+2,n); //pri("Q=%5.2f\n",Q);
if(Q*q<=0){m++; if(zmn==' ')
{//printf("go to Do, m=%2d n=%2d\n",m,n);
goto Do;}
return 0;}
D=f(m+1,n+2); //pri("D=%5.2f\n",D);
if(D*d<=0){n++; if(zmn==' ') goto Ri; return 0;}

return 0;}//end drift

DB conto(FILE *o,DB *G,DB *F,char *Z,DB *X, DB *Y,int M,int N,DB L,DB L1,DB L2)
{int m,n; int M1=M+1,N1=N+1;  DB w,	b,d, p,q, x,y;
printf("conto (copyleft 2008 by Dmitrii Kouznetsov) draws level L=%6.3f\n",L);

//for(n=N;n>=0;n--){DO(m,M1)printf("%5.2f",G[m*N1+n]); printf("\n");}
//getchar();

//DO(m,M1){ M(X[m],Y[0]);L(X[m],Y[N]);}
//DO(n,N1){ M(X[0],Y[n]);L(X[M],Y[n]);}
//fprintf(o,".001 W 0 0 0 RGB S\n");

DO(m,M1)DO(n,N1)z(m,n)=' ';
DO(m,M1)DO(n,N1)
{ w=G[m*N1+n]-L;
if(L1<w && w<L2) { F[m*N1+n]=w;}
else{ //o(X[m],Y[n]);
F[m*N1+n]=0; z(m,n)='p';if(m> 0) z(m-1,n  )='q';
if(n>0) {z(m,n-1)='b';  if(m> 0 )z(m-1,n-1)='d';}
}
}

//for(n=N;n>=0;n--){DO(m,M1)pri("%5.2f",F[m*N1+n]); printf("\n");}
//for(n=N;n>=0;n--){DO(m,M1)printf("%2c" , Z[m*N1+n]); printf("\n");}
//getchar();

//printf("Z1 Z2= %c %d   %c %d \n",Z[1],Z[1],Z[2],Z[2]);

//DB t,u,v;//Begin with singularities
// if singularity at the down-left of the cell

DO(m,M-1)
DO(n,N-1)
{ if(zmn=='p')
{bdpq; //pri("Sp: %2d %2d %5.2f %5.2f %5.2f %5.3f\n",m,n,b,d,p,q);
if(b*d<0&&z(m,n+1)==' '){x=Xm+(XM-Xm)*b/(b-d);y=YN;Mxy; drift(o,F,Z,X,Y,M,N,m,n+1,UPP);}
if(q*d<0&&z(m+1,n)==' '){y=Yn+(YN-Yn)*q/(q-d);x=XM;Mxy; drift(o,F,Z,X,Y,M,N,m+1,n,RIG);}
if(d*d==0&&z(m+1,n+1)==' '){                    M(XM,YN); drift(o,F,Z,X,Y,M,N,m+1,n+1,RIG);}
}
}

// Check for singularity at down-right
for(m=1;m<M;m++)
DO(n,N-1)
{if(zmn=='q') //how about to go up-left?
{bdpq; //pri("Sq: %2d %2d %5.2f %5.2f %5.2f %5.3f\n",m,n,b,d,p,q);
if(b*d<0&&z(m,n+1)==' '){x=Xm+(XM-Xm)*b/(b-d);y=YN;Mxy;drift(o,F,Z,X,Y,M,N,m,n+1,UPP);}
if(b*p<0&&z(m-1,n)==' '){y=Yn+(YN-Yn)*p/(p-b);x=Xm;Mxy;drift(o,F,Z,X,Y,M,N,m-1,n,LEF);}
if(b*b==0&&z(m-1,n+1)==' '){                    M(Xm,YN);drift(o,F,Z,X,Y,M,N,m-1,n+1,LEF);}
}
}

//Check for singularity at the top left corger. How about to go down-right?
DO(m,M-1)
for(n=1;n<N;n++)
{ if(zmn=='b')
{bdpq; //pri("Sb: %2d %2d %5.2f %5.2f %5.2f %5.3f\n",m,n,b,d,p,q);
if(q*p<0&&z(m,n-1)==' '){x=Xm+(XM-Xm)*p/(p-q);y=Yn;Mxy;drift(o,F,Z,X,Y,M,N,m,n-1,DOW);}
if(q*d<0&&z(m+1,n)==' '){y=Yn+(YN-Yn)*q/(q-d);x=XM;Mxy;drift(o,F,Z,X,Y,M,N,m+1,n,RIG);}
if(q*q==0&&z(m-1,n-1)==' '){                  M(XM,Yn);drift(o,F,Z,X,Y,M,N,m+1,n-1,RIG);}
}
}

for(m=1;m<M;m++)
for(n=1;n<N;n++)
{ if(zmn=='d') // singularity at the up-right corner of this sell. go down-left?
{bdpq; //pri("Sd: %2d %2d %5.2f %5.2f %5.2f %5.3f\n",m,n,b,d,p,q);
if(p*q<0&&z(m,n-1)==' '){x=Xm+(XM-Xm)*p/(p-q);y=Yn;Mxy;drift(o,F,Z,X,Y,M,N,m,n-1,DOW);}
if(p*b<0&&z(n-1,n)==' '){y=Yn+(YN-Yn)*p/(p-b);x=Xm;Mxy;drift(o,F,Z,X,Y,M,N,m-1,n,LEF);}
if(p*p==0&&z(m-1,n-1)==' '){                  M(Xm,Yn);drift(o,F,Z,X,Y,M,N,m-1,n-1,LEF);}
} }

//Trace the margin of the domain

n=0; // printf("n=%3d\n",n);
DO(m,M)
{ if(zmn==' ')	{ bdpq;
if(p*q<=0){  if(p>q || q>p)
{  x=Xm+(XM-Xm)*p/(p-q);
y=Yn; Mxy;
drift(o,F,Z,X,Y,M,N,m,n,UPP);}}
}
}
n=N-1; //printf("n=%3d\n",n);
DO(m,M)
{  if(zmn==' '){bdpq;
if(b*d<=0){ if(b>d || d>b)
{	x=Xm+(XM-Xm)*b/(b-d);
y=YN; Mxy;
drift(o,F,Z,X,Y,M,N,m,n,DOW);}}
}
}

m=0; //printf("m=%3d\n",m);
DO(n,N)
{  if(zmn==' '){bdpq;
if(b*p<=0) { if(p>b || p<b)
{	y=Yn+(YN-Yn)*p/(p-b);
x=Xm; Mxy;
drift(o,F,Z,X,Y,M,N,m,n,RIG);}}
}
}

// This was repaired
m=M-1; //printf("m=%3d\n",m);
DO(n,N)
{  if(zmn==' '){bdpq;
if(d*q<=0) { if( q>d || q<d  )
{ 	y=Yn+(YN-Yn)*q/(q-d);
x=XM; Mxy;
drift(o,F,Z,X,Y,M,N,m,n,LEF);}}
}
}

//Check if any loops inside the domain
for(m=1;m<M-1;m++)
for(n=1;n<N-1;n++) //DO(n,N)DO(m,M)
{
if(zmn==' ')	{ bdpq;
if(d*q<0){     y=Yn+(YN-Yn)*q/(q-d); x=XM;Mxy;
drift(o,F,Z,X,Y,M,N,m+1,n,RIG);
if(zmn==' '){ Mxy;
drift(o,F,Z,X,Y,M,N,m,n,LEF);
}
}
}
}

//   if(zmn==' ')	{ if(b*d<0){ 	x=Xm+(XM-Xm)*b/(b-d);	 y=YN; Mxy;
//				  drift(o,F,Z,X,Y,M,N,m,n,UPP);}}}

return 0;}
//end
#undef Mxy
#undef Lxy
#undef f
#undef z
#undef zmn
#undef zMn
#undef zmN
#undef zMN
#undef fmn
#undef fMn
#undef fmN
#undef fMN
#undef Xm
#undef XM
#undef Yn
#undef YN
#undef bdpq
#undef UPP
#undef LEF
#undef DOW
#undef RIG


// end of code //en.citizendium.org/wiki?title=ContourPlot/code/conto.cin //