internal static BigInteger pow2ModPow(BigInteger _base, BigInteger exponent, int j)
{
// PRE: (base > 0), (exponent > 0) and (j > 0)
BigInteger res = BigInteger.ONE;
BigInteger e = exponent.copy();
BigInteger baseMod2toN = _base.copy();
BigInteger res2;
/*
* If 'base' is odd then it's coprime with 2^j and phi(2^j) = 2^(j-1);
* so we can reduce reduce the exponent (mod 2^(j-1)).
*/
if (_base.testBit(0))
{
inplaceModPow2(e, j - 1);
}
inplaceModPow2(baseMod2toN, j);
for (int i = e.bitLength() - 1; i >= 0; i--)
{
res2 = res.copy();
inplaceModPow2(res2, j);
res = res.multiply(res2);
if (BitLevel.testBit(e, i))
{
res = res.multiply(baseMod2toN);
inplaceModPow2(res, j);
}
}
inplaceModPow2(res, j);
return(res);
}
private static bool millerRabin(BigInteger n, int t)
{
// PRE: n >= 0, t >= 0
BigInteger x; // x := UNIFORM{2...n-1}
BigInteger y; // y := x^(q * 2^j) mod n
BigInteger n_minus_1 = n.subtract(BigInteger.ONE); // n-1
int bitLength = n_minus_1.bitLength(); // ~ log2(n-1)
// (q,k) such that: n-1 = q * 2^k and q is odd
int k = n_minus_1.getLowestSetBit();
BigInteger q = n_minus_1.shiftRight(k);
Random rnd = new Random();
for (int i = 0; i < t; i++)
{
// To generate a witness 'x', first it use the primes of table
if (i < primes.Length)
{
x = BIprimes[i];
}
else /*
* It generates random witness only if it's necesssary. Note
* that all methods would call Miller-Rabin with t <= 50 so
* this part is only to do more robust the algorithm
*/
{
do
{
x = new BigInteger(bitLength, rnd);
} while ((x.compareTo(n) >= BigInteger.EQUALS) || (x.sign == 0) ||
x.isOne());
}
y = x.modPow(q, n);
if (y.isOne() || y.Equals(n_minus_1))
{
continue;
}
for (int j = 1; j < k; j++)
{
if (y.Equals(n_minus_1))
{
continue;
}
y = y.multiply(y).mod(n);
if (y.isOne())
{
return(false);
}
}
if (!y.Equals(n_minus_1))
{
return(false);
}
}
return(true);
}
internal static BigInteger slidingWindow(BigInteger x2, BigInteger a2, BigInteger exponent, BigInteger modulus, int n2)
{
// fill odd low pows of a2
BigInteger[] pows = new BigInteger[8];
BigInteger res = x2;
int lowexp;
BigInteger x3;
int acc3;
pows[0] = a2;
x3 = monPro(a2, a2, modulus, n2);
for (int i = 1; i <= 7; i++)
{
pows[i] = monPro(pows[i - 1], x3, modulus, n2);
}
for (int i = exponent.bitLength() - 1; i >= 0; i--)
{
if (BitLevel.testBit(exponent, i))
{
lowexp = 1;
acc3 = i;
for (int j = Math.Max(i - 3, 0); j <= i - 1; j++)
{
if (BitLevel.testBit(exponent, j))
{
if (j < acc3)
{
acc3 = j;
lowexp = (lowexp << (i - j)) ^ 1;
}
else
{
lowexp = lowexp ^ (1 << (j - acc3));
}
}
}
for (int j = acc3; j <= i; j++)
{
res = monPro(res, res, modulus, n2);
}
res = monPro(pows[(lowexp - 1) >> 1], res, modulus, n2);
i = acc3;
}
else
{
res = monPro(res, res, modulus, n2);
}
}
return(res);
}
internal static BigInteger squareAndMultiply(BigInteger x2, BigInteger a2, BigInteger exponent, BigInteger modulus, int n2)
{
BigInteger res = x2;
for (int i = exponent.bitLength() - 1; i >= 0; i--)
{
res = monPro(res, res, modulus, n2);
if (BitLevel.testBit(exponent, i))
{
res = monPro(res, a2, modulus, n2);
}
}
return(res);
}
internal static void inplaceModPow2(BigInteger x, int n)
{
// PRE: (x > 0) and (n >= 0)
int fd = n >> 5;
int leadingZeros;
if ((x.numberLength < fd) || (x.bitLength() <= n))
{
return;
}
leadingZeros = 32 - (n & 31);
x.numberLength = fd + 1;
unchecked {
x.digits[fd] &= (leadingZeros < 32) ? ((int)(((uint)-1) >> leadingZeros)) : 0;
}
x.cutOffLeadingZeroes();
}
internal static bool isProbablePrime(BigInteger n, int certainty)
{
// PRE: n >= 0;
if ((certainty <= 0) || ((n.numberLength == 1) && (n.digits[0] == 2)))
{
return(true);
}
// To discard all even numbers
if (!n.testBit(0))
{
return(false);
}
// To check if 'n' exists in the table (it fit in 10 bits)
if ((n.numberLength == 1) && ((n.digits[0] & 0XFFFFFC00) == 0))
{
return(Array.BinarySearch(primes, n.digits[0]) >= 0);
}
// To check if 'n' is divisible by some prime of the table
for (int i = 1; i < primes.Length; i++)
{
if (Division.remainderArrayByInt(n.digits, n.numberLength,
primes[i]) == 0)
{
return(false);
}
}
// To set the number of iterations necessary for Miller-Rabin test
int ix;
int bitLength = n.bitLength();
for (ix = 2; bitLength < BITS[ix]; ix++)
{
;
}
certainty = Math.Min(ix, 1 + ((certainty - 1) >> 1));
return(millerRabin(n, certainty));
}
internal static bool isProbablePrime(BigInteger n, int certainty)
{
// PRE: n >= 0;
if ((certainty <= 0) || ((n.numberLength == 1) && (n.digits[0] == 2))) {
return true;
}
// To discard all even numbers
if (!n.testBit(0)) {
return false;
}
// To check if 'n' exists in the table (it fit in 10 bits)
if ((n.numberLength == 1) && ((n.digits[0] & 0XFFFFFC00) == 0)) {
return (Array.BinarySearch(primes, n.digits[0]) >= 0);
}
// To check if 'n' is divisible by some prime of the table
for (int i = 1; i < primes.Length; i++) {
if (Division.remainderArrayByInt(n.digits, n.numberLength,
primes[i]) == 0) {
return false;
}
}
// To set the number of iterations necessary for Miller-Rabin test
int ix;
int bitLength = n.bitLength();
for (ix = 2; bitLength < BITS[ix]; ix++) {
;
}
certainty = Math.Min(ix, 1 + ((certainty - 1) >> 1));
return millerRabin(n, certainty);
}
internal static BigInteger nextProbablePrime(BigInteger n)
{
// PRE: n >= 0
int i, j;
int certainty;
int gapSize = 1024; // for searching of the next probable prime number
int[] modules = new int[primes.Length];
bool[] isDivisible = new bool[gapSize];
BigInteger startPoint;
BigInteger probPrime;
// If n < "last prime of table" searches next prime in the table
if ((n.numberLength == 1) && (n.digits[0] >= 0)
&& (n.digits[0] < primes[primes.Length - 1])) {
for (i = 0; n.digits[0] >= primes[i]; i++) {
;
}
return BIprimes[i];
}
/*
* Creates a "N" enough big to hold the next probable prime Note that: N <
* "next prime" < 2*N
*/
startPoint = new BigInteger(1, n.numberLength,
new int[n.numberLength + 1]);
Array.Copy(n.digits, startPoint.digits, n.numberLength);
// To fix N to the "next odd number"
if (n.testBit(0)) {
Elementary.inplaceAdd(startPoint, 2);
} else {
startPoint.digits[0] |= 1;
}
// To set the improved certainly of Miller-Rabin
j = startPoint.bitLength();
for (certainty = 2; j < BITS[certainty]; certainty++) {
;
}
// To calculate modules: N mod p1, N mod p2, ... for first primes.
for (i = 0; i < primes.Length; i++) {
modules[i] = Division.remainder(startPoint, primes[i]) - gapSize;
}
while (true) {
// At this point, all numbers in the gap are initialized as
// probably primes
Array.Clear(isDivisible, 0, isDivisible.Length);
// To discard multiples of first primes
for (i = 0; i < primes.Length; i++) {
modules[i] = (modules[i] + gapSize) % primes[i];
j = (modules[i] == 0) ? 0 : (primes[i] - modules[i]);
for (; j < gapSize; j += primes[i]) {
isDivisible[j] = true;
}
}
// To execute Miller-Rabin for non-divisible numbers by all first
// primes
for (j = 0; j < gapSize; j++) {
if (!isDivisible[j]) {
probPrime = startPoint.copy();
Elementary.inplaceAdd(probPrime, j);
if (millerRabin(probPrime, certainty)) {
return probPrime;
}
}
}
Elementary.inplaceAdd(startPoint, gapSize);
}
}
internal static BigInteger nextProbablePrime(BigInteger n)
{
// PRE: n >= 0
int i, j;
int certainty;
int gapSize = 1024; // for searching of the next probable prime number
int[] modules = new int[primes.Length];
bool[] isDivisible = new bool[gapSize];
BigInteger startPoint;
BigInteger probPrime;
// If n < "last prime of table" searches next prime in the table
if ((n.numberLength == 1) && (n.digits[0] >= 0) &&
(n.digits[0] < primes[primes.Length - 1]))
{
for (i = 0; n.digits[0] >= primes[i]; i++)
{
;
}
return(BIprimes[i]);
}
/*
* Creates a "N" enough big to hold the next probable prime Note that: N <
* "next prime" < 2*N
*/
startPoint = new BigInteger(1, n.numberLength,
new int[n.numberLength + 1]);
Array.Copy(n.digits, startPoint.digits, n.numberLength);
// To fix N to the "next odd number"
if (n.testBit(0))
{
Elementary.inplaceAdd(startPoint, 2);
}
else
{
startPoint.digits[0] |= 1;
}
// To set the improved certainly of Miller-Rabin
j = startPoint.bitLength();
for (certainty = 2; j < BITS[certainty]; certainty++)
{
;
}
// To calculate modules: N mod p1, N mod p2, ... for first primes.
for (i = 0; i < primes.Length; i++)
{
modules[i] = Division.remainder(startPoint, primes[i]) - gapSize;
}
while (true)
{
// At this point, all numbers in the gap are initialized as
// probably primes
Array.Clear(isDivisible, 0, isDivisible.Length);
// To discard multiples of first primes
for (i = 0; i < primes.Length; i++)
{
modules[i] = (modules[i] + gapSize) % primes[i];
j = (modules[i] == 0) ? 0 : (primes[i] - modules[i]);
for (; j < gapSize; j += primes[i])
{
isDivisible[j] = true;
}
}
// To execute Miller-Rabin for non-divisible numbers by all first
// primes
for (j = 0; j < gapSize; j++)
{
if (!isDivisible[j])
{
probPrime = startPoint.copy();
Elementary.inplaceAdd(probPrime, j);
if (millerRabin(probPrime, certainty))
{
return(probPrime);
}
}
}
Elementary.inplaceAdd(startPoint, gapSize);
}
}
internal static BigInteger squareAndMultiply(BigInteger x2, BigInteger a2, BigInteger exponent,BigInteger modulus, int n2 )
{
BigInteger res = x2;
for (int i = exponent.bitLength() - 1; i >= 0; i--) {
res = monPro(res,res,modulus, n2);
if (BitLevel.testBit(exponent, i)) {
res = monPro(res, a2, modulus, n2);
}
}
return res;
}
internal static BigInteger slidingWindow(BigInteger x2, BigInteger a2, BigInteger exponent,BigInteger modulus, int n2)
{
// fill odd low pows of a2
BigInteger[] pows = new BigInteger[8];
BigInteger res = x2;
int lowexp;
BigInteger x3;
int acc3;
pows[0] = a2;
x3 = monPro(a2,a2,modulus,n2);
for (int i = 1; i <= 7; i++){
pows[i] = monPro(pows[i-1],x3,modulus,n2) ;
}
for (int i = exponent.bitLength()-1; i>=0;i--){
if( BitLevel.testBit(exponent,i) ) {
lowexp = 1;
acc3 = i;
for(int j = Math.Max(i-3,0);j <= i-1 ;j++) {
if (BitLevel.testBit(exponent,j)) {
if (j<acc3) {
acc3 = j;
lowexp = (lowexp << (i-j))^1;
} else {
lowexp = lowexp^(1<<(j-acc3));
}
}
}
for(int j = acc3; j <= i; j++) {
res = monPro(res,res,modulus,n2);
}
res = monPro(pows[(lowexp-1)>>1], res, modulus,n2);
i = acc3 ;
}else{
res = monPro(res, res, modulus, n2) ;
}
}
return res;
}
internal static BigInteger modInverseLorencz(BigInteger a, BigInteger modulo)
{
int max = Math.Max(a.numberLength, modulo.numberLength);
int[] uDigits = new int[max + 1]; // enough place to make all the inplace operation
int[] vDigits = new int[max + 1];
Array.Copy(modulo.digits, uDigits, modulo.numberLength);
Array.Copy(a.digits, vDigits, a.numberLength);
BigInteger u = new BigInteger(modulo.sign, modulo.numberLength,
uDigits);
BigInteger v = new BigInteger(a.sign, a.numberLength, vDigits);
BigInteger r = new BigInteger(0, 1, new int[max + 1]); // BigInteger.ZERO;
BigInteger s = new BigInteger(1, 1, new int[max + 1]);
s.digits[0] = 1;
// r == 0 && s == 1, but with enough place
int coefU = 0, coefV = 0;
int n = modulo.bitLength();
int k;
while (!isPowerOfTwo(u, coefU) && !isPowerOfTwo(v, coefV)) {
// modification of original algorithm: I calculate how many times the algorithm will enter in the same branch of if
k = howManyIterations(u, n);
if (k != 0) {
BitLevel.inplaceShiftLeft(u, k);
if (coefU >= coefV) {
BitLevel.inplaceShiftLeft(r, k);
} else {
BitLevel.inplaceShiftRight(s, Math.Min(coefV - coefU, k));
if (k - ( coefV - coefU ) > 0) {
BitLevel.inplaceShiftLeft(r, k - coefV + coefU);
}
}
coefU += k;
}
k = howManyIterations(v, n);
if (k != 0) {
BitLevel.inplaceShiftLeft(v, k);
if (coefV >= coefU) {
BitLevel.inplaceShiftLeft(s, k);
} else {
BitLevel.inplaceShiftRight(r, Math.Min(coefU - coefV, k));
if (k - ( coefU - coefV ) > 0) {
BitLevel.inplaceShiftLeft(s, k - coefU + coefV);
}
}
coefV += k;
}
if (u.signum() == v.signum()) {
if (coefU <= coefV) {
Elementary.completeInPlaceSubtract(u, v);
Elementary.completeInPlaceSubtract(r, s);
} else {
Elementary.completeInPlaceSubtract(v, u);
Elementary.completeInPlaceSubtract(s, r);
}
} else {
if (coefU <= coefV) {
Elementary.completeInPlaceAdd(u, v);
Elementary.completeInPlaceAdd(r, s);
} else {
Elementary.completeInPlaceAdd(v, u);
Elementary.completeInPlaceAdd(s, r);
}
}
if (v.signum() == 0 || u.signum() == 0){
throw new ArithmeticException("BigInteger not invertible");
}
}
if (isPowerOfTwo(v, coefV)) {
r = s;
if (v.signum() != u.signum())
u = u.negate();
}
if (u.testBit(n)) {
if (r.signum() < 0) {
r = r.negate();
} else {
r = modulo.subtract(r);
}
}
if (r.signum() < 0) {
r = r.add(modulo);
}
return r;
}
internal static void inplaceModPow2(BigInteger x, int n)
{
// PRE: (x > 0) and (n >= 0)
int fd = n >> 5;
int leadingZeros;
if ((x.numberLength < fd) || (x.bitLength() <= n)) {
return;
}
leadingZeros = 32 - (n & 31);
x.numberLength = fd + 1;
unchecked {
x.digits[fd] &= (leadingZeros < 32) ? ((int)(((uint)-1) >> leadingZeros)) : 0;
}
x.cutOffLeadingZeroes();
}
internal static BigInteger modInverseLorencz(BigInteger a, BigInteger modulo)
{
int max = Math.Max(a.numberLength, modulo.numberLength);
int[] uDigits = new int[max + 1]; // enough place to make all the inplace operation
int[] vDigits = new int[max + 1];
Array.Copy(modulo.digits, uDigits, modulo.numberLength);
Array.Copy(a.digits, vDigits, a.numberLength);
BigInteger u = new BigInteger(modulo.sign, modulo.numberLength,
uDigits);
BigInteger v = new BigInteger(a.sign, a.numberLength, vDigits);
BigInteger r = new BigInteger(0, 1, new int[max + 1]); // BigInteger.ZERO;
BigInteger s = new BigInteger(1, 1, new int[max + 1]);
s.digits[0] = 1;
// r == 0 && s == 1, but with enough place
int coefU = 0, coefV = 0;
int n = modulo.bitLength();
int k;
while (!isPowerOfTwo(u, coefU) && !isPowerOfTwo(v, coefV))
{
// modification of original algorithm: I calculate how many times the algorithm will enter in the same branch of if
k = howManyIterations(u, n);
if (k != 0)
{
BitLevel.inplaceShiftLeft(u, k);
if (coefU >= coefV)
{
BitLevel.inplaceShiftLeft(r, k);
}
else
{
BitLevel.inplaceShiftRight(s, Math.Min(coefV - coefU, k));
if (k - (coefV - coefU) > 0)
{
BitLevel.inplaceShiftLeft(r, k - coefV + coefU);
}
}
coefU += k;
}
k = howManyIterations(v, n);
if (k != 0)
{
BitLevel.inplaceShiftLeft(v, k);
if (coefV >= coefU)
{
BitLevel.inplaceShiftLeft(s, k);
}
else
{
BitLevel.inplaceShiftRight(r, Math.Min(coefU - coefV, k));
if (k - (coefU - coefV) > 0)
{
BitLevel.inplaceShiftLeft(s, k - coefU + coefV);
}
}
coefV += k;
}
if (u.signum() == v.signum())
{
if (coefU <= coefV)
{
Elementary.completeInPlaceSubtract(u, v);
Elementary.completeInPlaceSubtract(r, s);
}
else
{
Elementary.completeInPlaceSubtract(v, u);
Elementary.completeInPlaceSubtract(s, r);
}
}
else
{
if (coefU <= coefV)
{
Elementary.completeInPlaceAdd(u, v);
Elementary.completeInPlaceAdd(r, s);
}
else
{
Elementary.completeInPlaceAdd(v, u);
Elementary.completeInPlaceAdd(s, r);
}
}
if (v.signum() == 0 || u.signum() == 0)
{
throw new ArithmeticException("BigInteger not invertible");
}
}
if (isPowerOfTwo(v, coefV))
{
r = s;
if (v.signum() != u.signum())
{
u = u.negate();
}
}
if (u.testBit(n))
{
if (r.signum() < 0)
{
r = r.negate();
}
else
{
r = modulo.subtract(r);
}
}
if (r.signum() < 0)
{
r = r.add(modulo);
}
return(r);
}
private void setUnscaledValue(BigInteger unscaledValue)
{
this.intVal = unscaledValue;
this._bitLength = unscaledValue.bitLength();
if(this._bitLength < 64) {
this.smallValue = unscaledValue.longValue();
}
}
private static BigDecimal divideBigIntegers(BigInteger scaledDividend, BigInteger scaledDivisor, int scale, RoundingMode roundingMode)
{
BigInteger[] quotAndRem = scaledDividend.divideAndRemainder(scaledDivisor); // quotient and remainder
// If after division there is a remainder...
BigInteger quotient = quotAndRem[0];
BigInteger remainder = quotAndRem[1];
if (remainder.signum() == 0) {
return new BigDecimal(quotient, scale);
}
int sign = scaledDividend.signum() * scaledDivisor.signum();
int compRem; // 'compare to remainder'
if(scaledDivisor.bitLength() < 63) { // 63 in order to avoid out of long after <<1
long rem = remainder.longValue();
long divisor = scaledDivisor.longValue();
compRem = longCompareTo(Math.Abs(rem) << 1,Math.Abs(divisor));
// To look if there is a carry
compRem = roundingBehavior(quotient.testBit(0) ? 1 : 0,
sign * (5 + compRem), roundingMode);
} else {
// Checking if: remainder * 2 >= scaledDivisor
compRem = remainder.abs().shiftLeftOneBit().compareTo(scaledDivisor.abs());
compRem = roundingBehavior(quotient.testBit(0) ? 1 : 0,
sign * (5 + compRem), roundingMode);
}
if (compRem != 0) {
if(quotient.bitLength() < 63) {
return valueOf(quotient.longValue() + compRem,scale);
}
quotient = quotient.add(BigInteger.valueOf(compRem));
return new BigDecimal(quotient, scale);
}
// Constructing the result with the appropriate unscaled value
return new BigDecimal(quotient, scale);
}
