[449fbf] | 1 | /////////////////////////////////////////////////////////////////////////////// |
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[4c20ee] | 2 | version="version aksaka.lib 4.0.0.0 Jun_2013 "; |
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[449fbf] | 3 | category="Teaching"; |
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| 4 | info=" |
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[1a3911] | 5 | LIBRARY: aksaka.lib Procedures for primality testing after Agrawal, Saxena, Kayal |
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[449fbf] | 6 | AUTHORS: Christoph Mang |
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| 7 | |
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[1a3911] | 8 | OVERVIEW: |
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[449fbf] | 9 | Algorithms for primality testing in polynomial time |
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| 10 | based on the ideas of Agrawal, Saxena and Kayal. |
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| 11 | |
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| 12 | PROCEDURES: |
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| 13 | |
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[1a3911] | 14 | fastExpt(a,m,n) a^m for numbers a,m; if a^k>n n+1 is returned |
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[449fbf] | 15 | log2(n) logarithm to basis 2 of n |
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| 16 | PerfectPowerTest(n) checks if there are a,b>1, so that a^b=n |
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| 17 | wurzel(r) square root of number r |
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[0dd77c2] | 18 | euler(r) phi-function of Euler |
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[3754ca] | 19 | coeffmod(f,n) polynomial f modulo number n (coefficients mod n) |
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| 20 | powerpolyX(q,n,a,r) (polynomial a)^q modulo (poly r,number n) |
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[449fbf] | 21 | ask(n) ASK-Algorithm; deterministic Primality test |
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| 22 | "; |
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| 23 | |
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[abb4919] | 24 | LIB "crypto.lib"; |
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[449fbf] | 25 | LIB "ntsolve.lib"; |
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| 26 | |
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| 27 | /////////////////////////////////////////////////////////////// |
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| 28 | // // |
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[f3a11a] | 29 | // FAST (MODULAR) EXPONENTIATION // |
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[449fbf] | 30 | // // |
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[abb4919] | 31 | /////////////////////////////////////////////////////////////// |
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[1a3911] | 32 | proc fastExpt(number a,number m,number n) |
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| 33 | "USAGE: fastExpt(a,m,n); a, m, n = number; |
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[449fbf] | 34 | RETURN: the m-th power of a; if a^m>n the procedure returns n+1 |
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| 35 | NOTE: uses fast exponentiation |
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[1a3911] | 36 | EXAMPLE:example fastExpt; shows an example |
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[449fbf] | 37 | " |
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| 38 | { |
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[226c28] | 39 | number b,c,d; |
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| 40 | c=m; |
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| 41 | b=a; |
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| 42 | d=1; |
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[449fbf] | 43 | while(c>=1) |
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| 44 | { |
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[226c28] | 45 | if(b>n) |
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| 46 | { |
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[449fbf] | 47 | return(n+1); |
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[226c28] | 48 | } |
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[449fbf] | 49 | if((c mod 2)==1) |
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[226c28] | 50 | { |
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| 51 | d=d*b; |
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| 52 | if(d>n) |
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| 53 | { |
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| 54 | return(n+1); |
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| 55 | } |
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| 56 | } |
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| 57 | b=b^2; |
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| 58 | c=intPart(c/2); |
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[449fbf] | 59 | } |
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[226c28] | 60 | return(d) |
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[449fbf] | 61 | } |
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| 62 | example |
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| 63 | { "EXAMPLE:"; echo = 2; |
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| 64 | ring R = 0,x,dp; |
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[1a3911] | 65 | fastExpt(2,10,1022); |
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[449fbf] | 66 | } |
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[f3a11a] | 67 | //////////////////////////////////////////////////////////////////////////// |
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| 68 | proc coeffmod(poly f,number n) |
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[abb4919] | 69 | "USAGE: coeffmod(f,n); |
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[f3a11a] | 70 | ASSUME: poly f depends on at most var(1) of the basering |
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[abb4919] | 71 | RETURN: poly f modulo number n |
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[3754ca] | 72 | NOTE: at first the coefficients of the monomials of the polynomial f are |
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[abb4919] | 73 | determined, then their remainder modulo n is calculated, |
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[3754ca] | 74 | after that the polynomial 'is put together' again |
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[f3a11a] | 75 | EXAMPLE:example coeffmod; shows an example |
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[449fbf] | 76 | " |
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[abb4919] | 77 | { |
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[f3a11a] | 78 | matrix M=coeffs(f,var(1)); //Bestimmung der Polynomkoeffizienten |
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| 79 | int i=1; |
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| 80 | poly g; |
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[226c28] | 81 | int o=nrows(M); |
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[449fbf] | 82 | |
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[f3a11a] | 83 | while(i<=o) |
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[226c28] | 84 | { |
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| 85 | g=g+(leadcoef(M[i,1]) mod n)*var(1)^(i-1) ; |
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| 86 | // umwandeln der Koeffizienten in numbers, |
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| 87 | // Berechnung der Reste dieser numbers modulo n, |
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[3754ca] | 88 | // Polynom mit neuen Koeffizienten wieder zusammensetzen |
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[226c28] | 89 | i++; |
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| 90 | } |
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[f3a11a] | 91 | return(g); |
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[449fbf] | 92 | } |
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| 93 | example |
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[abb4919] | 94 | { "EXAMPLE:"; echo = 2; |
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[449fbf] | 95 | ring R = 0,x,dp; |
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[f3a11a] | 96 | poly f=2457*x4+52345*x3-98*x2+5; |
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| 97 | number n=3; |
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| 98 | coeffmod(f,n); |
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[abb4919] | 99 | } |
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[f3a11a] | 100 | ////////////////////////////////////////////////////////////////////////// |
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| 101 | proc powerpolyX(number q,number n,poly a,poly r) |
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[abb4919] | 102 | "USAGE: powerpolyX(q,n,a,r); |
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| 103 | RETURN: the q-th power of poly a modulo poly r and number n |
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[f3a11a] | 104 | EXAMPLE:example powerpolyX; shows an example |
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| 105 | " |
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| 106 | { |
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[226c28] | 107 | ideal I=r; |
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[abb4919] | 108 | |
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[226c28] | 109 | if(q==1){return(coeffmod(reduce(a,I),n));} |
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| 110 | if((q mod 5)==0){return(coeffmod(reduce(powerpolyX(q/5,n,a,r)^5,I),n));} |
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| 111 | if((q mod 4)==0){return(coeffmod(reduce(powerpolyX(q/4,n,a,r)^4,I),n));} |
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| 112 | if((q mod 3)==0){return(coeffmod(reduce(powerpolyX(q/3,n,a,r)^3,I),n));} |
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| 113 | if((q mod 2)==0){return(coeffmod(reduce(powerpolyX(q/2,n,a,r)^2,I),n));} |
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[f3a11a] | 114 | |
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| 115 | return(coeffmod(reduce(a*powerpolyX(q-1,n,a,r),I),n)); |
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[abb4919] | 116 | } |
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[f3a11a] | 117 | example |
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[abb4919] | 118 | { "EXAMPLE:"; echo = 2; |
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[f3a11a] | 119 | ring R=0,x,dp; |
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[449fbf] | 120 | poly a=3*x3-x2+5; |
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[f3a11a] | 121 | poly r=x7-1; |
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| 122 | number q=123; |
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| 123 | number n=5; |
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| 124 | powerpolyX(q,n,a,r); |
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[449fbf] | 125 | } |
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| 126 | /////////////////////////////////////////////////////////////// |
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| 127 | // // |
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| 128 | // GENERAL PROCEDURES // |
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| 129 | // // |
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| 130 | /////////////////////////////////////////////////////////////// |
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| 131 | proc log2(number x) |
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| 132 | "USAGE: log2(x); |
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| 133 | RETURN: logarithm to basis 2 of x |
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| 134 | NOTE: calculates the natural logarithm of x with a power-series |
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| 135 | of the ln, then the basis is changed to 2 |
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| 136 | EXAMPLE: example log2; shows an example |
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| 137 | " |
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| 138 | { |
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[226c28] | 139 | number b,c,d,t,l; |
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| 140 | int k; |
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[449fbf] | 141 | // log2=logarithmus zur basis 2, |
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| 142 | // log=natuerlicher logarithmus |
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[226c28] | 143 | b=100000000000000000000000000000000000000000000000000; |
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| 144 | c=141421356237309504880168872420969807856967187537695; // c/b=sqrt(2) |
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| 145 | d=69314718055994530941723212145817656807550013436026; // d/b=log(2) |
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[449fbf] | 146 | |
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[226c28] | 147 | //bringen x zunaechst zwischen 1/sqrt(2) und sqrt(2), so dass Reihe schnell |
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| 148 | //konvergiert, berechnen dann Reihe bis 30. Summanden und letztendlich |
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[0610f0e] | 149 | //log2(x)=log(x)/log(2)=(log(x/2^j)+j*log(2))/log(2) fuer grosse x |
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| 150 | //log2(x)=log(x)/log(2)=(log(x*2^j)-j*log(2))/log(2) fuer kleine x |
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[449fbf] | 151 | |
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[226c28] | 152 | number j=0; |
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| 153 | if(x<(b/c)) |
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| 154 | { |
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| 155 | while(x<(b/c)) |
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| 156 | { |
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| 157 | x=x*2; |
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| 158 | j=j+1; |
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| 159 | } |
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| 160 | t=(x-1)/(x+1); |
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| 161 | k=0; |
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| 162 | l=0; |
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| 163 | while(k<30) //fuer x*2^j wird Reihe bis k-tem Summanden berechnet |
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| 164 | { |
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| 165 | l=l+2*(t^(2*k+1))/(2*k+1); //l=log(x*2^j) nach k Summanden |
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| 166 | k=k+1; |
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| 167 | } |
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| 168 | return((l*b/d)-j); //log2(x)=log(x*2^j)/log(2)-j wird ausgegeben |
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| 169 | } |
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| 170 | while(x>(c/b)) |
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| 171 | { |
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| 172 | x=x/2; |
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[449fbf] | 173 | j=j+1; |
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[226c28] | 174 | } |
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[449fbf] | 175 | t=(x-1)/(x+1); |
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| 176 | k=0; |
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| 177 | l=0; |
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[226c28] | 178 | while(k<30) //fuer x/2^j wird Reihe bis k-tem Summanden berechnet |
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[449fbf] | 179 | { |
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[226c28] | 180 | l=l+2*(t^(2*k+1))/(2*k+1); //l=log(x/2^j) nach k Summanden |
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| 181 | k=k+1; |
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[449fbf] | 182 | } |
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[226c28] | 183 | return((l*b/d)+j); //hier wird log2(x)=log(x/2^j)/log(2)+j ausgegeben |
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[449fbf] | 184 | } |
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| 185 | example |
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| 186 | { "EXAMPLE:"; echo = 2; |
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| 187 | ring R = 0,x,dp; |
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| 188 | log2(1024); |
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| 189 | } |
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| 190 | ////////////////////////////////////////////////////////////////////////// |
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| 191 | proc wurzel(number r) |
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| 192 | "USAGE: wurzel(r); |
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[d2f488] | 193 | ASSUME: characteristic of basering is 0, r>=0 |
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[449fbf] | 194 | RETURN: number, square root of r |
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| 195 | EXAMPLE:example wurzel; shows an example |
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| 196 | " |
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| 197 | { |
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[226c28] | 198 | poly f=var(1)^2-r; //Wurzel wird als Nullstelle eines Polys |
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[0610f0e] | 199 | //mit proc nt_solve genaehert |
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[226c28] | 200 | def B=basering; |
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| 201 | ring R=(real,40),var(1),dp; |
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| 202 | poly g=imap(B,f); |
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| 203 | list l=nt_solve(g,1.1); |
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| 204 | number m=leadcoef(l[1][1]); |
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| 205 | setring B; |
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| 206 | return(imap(R,m)); |
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[449fbf] | 207 | } |
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| 208 | example |
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| 209 | { "EXAMPLE:"; echo = 2; |
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| 210 | ring R = 0,x,dp; |
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| 211 | wurzel(7629412809180100); |
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| 212 | } |
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| 213 | ////////////////////////////////////////////////////////////////////////// |
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| 214 | proc euler(number r) |
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| 215 | "USAGE: euler(r); |
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[0dd77c2] | 216 | RETURN: number phi(r), where phi is Eulers phi-function |
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[449fbf] | 217 | NOTE: first r is factorized with proc PollardRho, then phi(r) is |
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| 218 | calculated with the help of phi(p) of every factor p; |
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| 219 | EXAMPLE:example euler; shows an example |
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| 220 | " |
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| 221 | { |
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| 222 | list l=PollardRho(r,5000,1); //bestimmen der Primfaktoren von r |
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[226c28] | 223 | int k; |
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| 224 | number phi=r; |
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| 225 | for(k=1;k<=size(l);k++) |
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| 226 | { |
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| 227 | phi=phi-phi/l[k]; //berechnen phi(r) mit Hilfe der |
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| 228 | } //Primfaktoren und Eigenschaften der phi-Fktn |
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| 229 | return(phi); |
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[449fbf] | 230 | } |
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| 231 | example |
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| 232 | { "EXAMPLE:"; echo = 2; |
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| 233 | ring R = 0,x,dp; |
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| 234 | euler(99991); |
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| 235 | } |
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| 236 | /////////////////////////////////////////////////////////////// |
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| 237 | // // |
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| 238 | // PERFECT POWER TEST // |
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| 239 | // // |
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| 240 | /////////////////////////////////////////////////////////////// |
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| 241 | proc PerfectPowerTest(number n) |
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| 242 | "USAGE: PerfectPowerTest(n); |
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| 243 | RETURN: 0 if there are numbers a,b>1 with a^b=n; |
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| 244 | 1 if there are no numbers a,b>1 with a^b=n; |
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| 245 | if printlevel>=1 and there are a,b>1 with a^b=n, |
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| 246 | then a,b are printed |
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| 247 | EXAMPLE:example PerfectPowerTest; shows an example |
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| 248 | " |
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| 249 | { |
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| 250 | number a,b,c,e,f,m,l,p; |
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| 251 | b=2; |
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| 252 | l=log2(n); |
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| 253 | e=0; |
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| 254 | f=1; |
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| 255 | |
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| 256 | while(b<=l) |
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[226c28] | 257 | { |
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| 258 | a=1; |
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| 259 | c=n; |
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[449fbf] | 260 | |
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[226c28] | 261 | while(c-a>=2) |
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| 262 | { |
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| 263 | m=intPart((a+c)/2); |
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[1a3911] | 264 | p=fastExpt(m,b,n); |
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[449fbf] | 265 | |
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[226c28] | 266 | if(p==n) |
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| 267 | { |
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| 268 | if(printlevel>=1){"es existieren Zahlen a,b>1 mit a^b=n"; |
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| 269 | "a=";m;"b=";b;pause();} |
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| 270 | return(e); |
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| 271 | } |
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[449fbf] | 272 | |
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[226c28] | 273 | if(p<n) |
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| 274 | { |
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| 275 | a=m; |
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[449fbf] | 276 | } |
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[226c28] | 277 | else |
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| 278 | { |
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| 279 | c=m; |
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| 280 | } |
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| 281 | } |
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| 282 | b=b+1; |
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| 283 | } |
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[449fbf] | 284 | if(printlevel>=1){"es existieren keine Zahlen a,b>1 mit a^b=n";pause();} |
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| 285 | return(f); |
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| 286 | } |
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| 287 | example |
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| 288 | { "EXAMPLE:"; echo = 2; |
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| 289 | ring R = 0,x,dp; |
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| 290 | PerfectPowerTest(887503681); |
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| 291 | } |
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| 292 | /////////////////////////////////////////////////////////////// |
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| 293 | // // |
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| 294 | // ASK PRIMALITY TEST // |
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| 295 | // // |
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| 296 | /////////////////////////////////////////////////////////////// |
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| 297 | proc ask(number n) |
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| 298 | "USAGE: ask(n); |
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| 299 | ASSUME: n>1 |
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| 300 | RETURN: 0 if n is composite; |
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| 301 | 1 if n is prime; |
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| 302 | if printlevel>=1, you are informed what the procedure will do |
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| 303 | or has calculated |
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| 304 | NOTE: ASK-algorithm; uses proc powerpolyX for step 5 |
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| 305 | EXAMPLE:example ask; shows an example |
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| 306 | " |
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| 307 | { |
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| 308 | number c,p; |
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| 309 | c=0; |
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| 310 | p=1; |
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| 311 | |
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[226c28] | 312 | if(n==2) { return(p); } |
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| 313 | if(printlevel>=1){"Beginn: Test ob a^b=n fuer a,b>1";pause();} |
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| 314 | if(0==PerfectPowerTest(n)) // Schritt1 des ASK-Alg. |
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| 315 | { return(c); } |
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| 316 | if(printlevel>=1) |
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| 317 | { |
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| 318 | "Beginn: Berechnung von r, so dass ord(n) in Z/rZ groesser log2(n)^2 "; |
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| 319 | pause(); |
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| 320 | } |
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| 321 | number k,M,M2,b; |
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| 322 | int r; // Zeile 526-542: Schritt 2 |
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| 323 | M=log2(n); // darin sind die Schritte |
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| 324 | M2=intPart(M^2); // 3 und 4 integriert |
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| 325 | r=2; |
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[449fbf] | 326 | |
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[1e1ec4] | 327 | if(gcd(n,r)!=1) //falls ggt ungleich eins, Teiler von n gefunden, |
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[449fbf] | 328 | // Schritt 3 des ASK-Alg. |
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[226c28] | 329 | { |
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[449fbf] | 330 | if(printlevel>=1){"Zahl r gefunden mit r|n";"r=";r;pause();} |
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| 331 | return(c); |
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[226c28] | 332 | } |
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[0610f0e] | 333 | if(r==n-1) // falls diese Bedingung erfuellt ist, ist |
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| 334 | // ggT(a,n)=1 fuer 0<a<=r, schritt 4 des ASK-Alg. |
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[449fbf] | 335 | { |
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[226c28] | 336 | if(printlevel>=1){"ggt(r,n)=1 fuer alle 1<r<n";pause();} |
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| 337 | return(p); |
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[449fbf] | 338 | } |
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| 339 | k=1; |
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| 340 | b=1; |
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| 341 | |
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[0610f0e] | 342 | while(k<=M2) //Beginn des Ordnungstests fuer aktuelles r |
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[226c28] | 343 | { |
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| 344 | b=((b*n) mod r); |
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[0610f0e] | 345 | if(b==1) //tritt Bedingung ein so gilt fuer aktuelles r,k: |
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[226c28] | 346 | //n^k=1 mod r |
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| 347 | //tritt Bedingung ein, wird wegen k<=M2=intPart(log2(n)^2) |
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[0610f0e] | 348 | //r erhoeht,k=0 gesetzt und Ordnung erneut untersucht |
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| 349 | //tritt diese Bedingung beim groessten k=intPart(log2(n)^2) |
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[226c28] | 350 | //nicht ein, so ist ord_r_(n)>log2(n)^2 und Schleife |
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[0610f0e] | 351 | //wird nicht mehr ausgefuehrt |
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[449fbf] | 352 | { |
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[226c28] | 353 | if(r==2147483647) |
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[449fbf] | 354 | { |
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[0610f0e] | 355 | string e="error: r ueberschreitet integer Bereich und darf |
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[226c28] | 356 | nicht als Grad eines Polynoms verwendet werden"; |
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| 357 | return(e); |
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| 358 | } |
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| 359 | r=r+1; |
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[1e1ec4] | 360 | if(gcd(n,r)!=1) //falls ggt ungleich eins, Teiler von n gefunden, |
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[0610f0e] | 361 | //wird aufgrund von Schritt 3 des ASK-Alg. fuer |
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[226c28] | 362 | //jeden Kandidaten r getestet |
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| 363 | { |
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| 364 | if(printlevel>=1){"Zahl r gefunden mit r|n";"r=";r;pause();} |
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| 365 | return(c); |
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| 366 | } |
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[0610f0e] | 367 | if(r==n-1) //falls diese Bedingung erfuellt ist, |
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[226c28] | 368 | //ist n wegen Zeile 571 prim |
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[0610f0e] | 369 | //wird aufgrund von Schritt 4 des ASK-Alg. fuer |
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[226c28] | 370 | //jeden Kandidaten r getestet |
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| 371 | { |
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| 372 | if(printlevel>=1){"ggt(r,n)=1 fuer alle 1<r<n";pause();} |
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| 373 | return(p); |
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[449fbf] | 374 | } |
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| 375 | |
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[0610f0e] | 376 | k=0; //fuer neuen Kandidaten r, muss k fuer den |
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| 377 | //Ordnungstest zurueckgesetzt werden |
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[449fbf] | 378 | } |
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[226c28] | 379 | k=k+1; |
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| 380 | } |
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| 381 | if(printlevel>=1) |
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| 382 | { |
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| 383 | "Zahl r gefunden, so dass ord(n) in Z/rZ groesser log2(n)^2 "; |
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| 384 | "r=";r;pause(); |
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| 385 | } |
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| 386 | number l=1; // Zeile 603-628: Schritt 5 |
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[0610f0e] | 387 | poly f,g; // Zeile 618 ueberprueft Gleichungen fuer |
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[226c28] | 388 | // das jeweilige a |
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| 389 | g=var(1)^r-1; |
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| 390 | number grenze=intPart(wurzel(euler(r))*M); |
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| 391 | |
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| 392 | if(printlevel>=1) |
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| 393 | {"Beginn: Ueberpruefung ob (x+a)^n kongruent x^n+a mod (x^r-1,n) |
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| 394 | fuer 0<a<=intPart(wurzel(phi(r))*log2(n))=";grenze;pause(); |
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| 395 | } |
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| 396 | while(l<=grenze) // |
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| 397 | { |
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| 398 | if(printlevel>=1){"a=";l;} |
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| 399 | f=var(1)+l; |
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| 400 | if(powerpolyX(n,n,f,g)!=(var(1)^(int((n mod r)))+l)) |
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| 401 | { |
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| 402 | if(printlevel>=1) |
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| 403 | {"Fuer a=";l;"ist (x+a)^n nicht kongruent x^n+a mod (x^r-1,n)"; |
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| 404 | pause(); |
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| 405 | } |
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| 406 | return(c); |
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| 407 | } |
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| 408 | l=l+1; |
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| 409 | } |
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| 410 | if(printlevel>=1) |
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[449fbf] | 411 | {"(x+a)^n kongruent x^n+a mod (x^r-1,n) fuer 0<a<wurzel(phi(r))*log2(n)"; |
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[226c28] | 412 | pause(); |
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| 413 | } |
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| 414 | return(p); // Schritt 6 |
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[449fbf] | 415 | } |
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| 416 | example |
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| 417 | { "EXAMPLE:"; echo = 2; |
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| 418 | ring R = 0,x,dp; |
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[f3a11a] | 419 | //ask(100003); |
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| 420 | ask(32003); |
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[449fbf] | 421 | } |
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