77 lines
No EOL
1.9 KiB
R
Executable file
77 lines
No EOL
1.9 KiB
R
Executable file
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##############################
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# Calcule les ou le point d'intersection de deux cercle :
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# Cercle 1 de coordonnés (a1,b1) de rayon d1
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# Cercle 2 de coordonnés (a2,b2) de rayon d2
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# Precision = nombre de chiffre aprés la virgule
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##############################
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getIntersection=function(a1,b1,d1,a2,b2,d2,precision=5){
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# Compute E (cf paper)
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computeE=function(a1,b1,a2,b2){
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numerateur=-2*a1+2*a2;
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denominateur=-2*b1+2*b2;
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return(numerateur/denominateur);
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}
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# Compute F (cf paper)
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computeF=function(a1,b1,d1,a2,b2,d2){
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numerateur=a1^2+b1^2-a2^2-b2^2-d1^2+d2^2;
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denominateur=-2*b1+2*b2;
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return(numerateur/denominateur);
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}
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# Compute intersections if b1 != b2
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computeYNotEqual=function(a1,b1,d1,a2,b2,d2){
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E=computeE(a1,b1,a2,b2);
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F=computeF(a1,b1,d1,a2,b2,d2);
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A=E^2+1;
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B=(-2*a1+2*E*F+2*E*b1);
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C=2*F*b1+b1^2+a1^2+F^2-d1^2;
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values=polyroot(c(C,B,A));
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x=c();
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y=c();
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for(i in 1:length(values)){
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if(round(Im(values[i]),digit=precision)==0){
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x=c(x,Re(values[i]));
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y=c(y,-Re(values[i])*E-F);
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}
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}
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if(length(x)==0){
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return(NULL);
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}
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return(matrix(c(x,y),nrow=length(x),ncol=2));
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}
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# Compute intersections if b1 == b2 and a1 != a2
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computeYEqualAndXNotEqual=function(a1,b1,d1,a2,b2,d2){
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G=-((a1^2-a2^2-d1^2+d2^2)/(-2*a1+2*a2));
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A=1;
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B=-2*b1;
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C=G^2-2*G*a1+a1^2+b1^2-d1^2;
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values=polyroot(c(C,B,A));
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x=c();
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y=c();
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for(i in 1:length(values)){
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if(round(Im(values[i]),digit=precision)==0){
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x=c(x,G);
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y=c(y,Re(values[i]));
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}
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}
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if(length(y)==0){
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return(NULL);
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}
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return(matrix(c(x,y),nrow=length(y),ncol=2));
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}
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# Compute intersections
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if(b1!=b2){
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return(computeYNotEqual(a1,b1,d1,a2,b2,d2));
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}
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else if(a1!=a2){
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return(computeYEqualAndXNotEqual(a1,b1,d1,a2,b2,d2));
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}
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# No intersection found
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return(NULL);
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} |