P-Adic numbers, basic: Difference between revisions
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=={{header|C++}}==
This example displays p-adic numbers in standard mathematical format, consisting of a possibly infinite list of digits extending leftwards from the p-adic point.
<syntaxhighlight lang="c++">
#include <cmath>
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class P_adic {
public:
// Create a
P_adic(const uint32_t& prime, int32_t numerator, int32_t denominator) : prime(prime) {
if ( denominator == 0 ) {
throw std::invalid_argument("Denominator cannot be zero");
}
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// Process rational zero
if ( numerator == 0 ) {
digits.assign(DIGITS_SIZE, 0);
order = ORDER_MAX;
return;
}
// Remove multiples of 'prime' and adjust the order of the
while ( modulo_prime(numerator) == 0 ) {
numerator /= static_cast<int32_t>(prime);
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}
// Standard calculation of
const uint64_t inverse = modulo_inverse(denominator);
while ( digits.size() < DIGITS_SIZE ) {
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}
// Return the sum of this
P_adic add(P_adic other) {
if ( prime != other.prime ) {
throw std::invalid_argument("Cannot add p-adic's with different primes");
}
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std::vector<uint32_t> result;
// Adjust the digits so that the
for ( int32_t i = 0; i < -order + other.order; ++i ) {
other_digits.insert(other_digits.begin(), 0);
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}
// Return the Rational representation of this
Rational convert_to_rational() {
std::vector<uint32_t> numbers = digits;
// Zero
if ( numbers.empty() || all_zero_digits(numbers) ) {
return Rational(1, 0);
}
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}
// Return a string representation of this
std::string to_string() {
std::vector<uint32_t> numbers = digits;
}▼
▲ pad_with_zeros(digits);
std::string result = "";
for ( int64_t i =
result += std::to_string(digits[i]);
}
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for ( int32_t i = 0; i < order; ++i ) {
result += "0";
result.erase(result.begin());▼
}
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} else {
result.insert(result.length() + order, ".");
while ( result[result.length() - 1] == '0' ) {
}
}
return " ..." + result.substr(result.length() - PRECISION - 1);
}
private:
/**
* Create a
*
*
* 'order' > 0 shifts the vector 'order' places to the left and
* 'order' < 0 shifts the vector 'order' places to the right.
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}
// Transform the given vector of digits representing a
// into a vector which represents the negation of the
void negate_digits(std::vector<uint32_t>& numbers) {
numbers[0] = modulo_prime(
for ( uint64_t i = 1; i < numbers.size(); ++i ) {
numbers[i] = prime - 1 - numbers[i];
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uint32_t modulo_inverse(const uint32_t& number) const {
uint32_t inverse = 1;
while ( modulo_prime(
inverse += 1;
}
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}
// The given vector is padded on the right by zeros up to a maximum length of '
void pad_with_zeros(std::vector<uint32_t>& vector) {
while ( vector.size() <
vector.emplace_back(0);
}
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P_adic sum = padic_one.add(padic_two);
std::cout << "sum => " << sum.to_string() << std::endl;
std::cout << "Rational = " << sum.convert_to_rational().to_string() << std::endl;
std::cout << std::endl;
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3-adic numbers:
-2 / 87 => ...101020111222001212021110002210102011122.2
4 / 97 => ...
sum => ...201011000022210220101111202212220210220.2
Rational = 154 / 8439
7-adic numbers:
5 / 8 => ...
353 / 30809 => ...
sum => ...
Rational = 156869 / 246472
</pre>
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=={{header|Java}}==
This example displays p-adic numbers in standard mathematical format, consisting of a possibly infinite list of digits extending leftwards from the p-adic point.
<syntaxhighlight lang="java">
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
public final class PAdicNumbersBasic {
public static void main(String[] args) {
System.out.println("3-adic numbers:");
Padic padicOne = new Padic(3, -5, 9);
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}
final class Padic {
/**
* Create a p-adic
*/
public Padic(int aPrime, int aNumerator, int aDenominator) {
if ( aDenominator == 0 ) {
throw new IllegalArgumentException("Denominator cannot be zero");
}
prime = aPrime;
digits = new ArrayList<Integer>(
order = 0;
// Process rational zero
if ( aNumerator == 0 ) {
order =
return;
}
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// Standard calculation of p-adic digits
final long inverse = moduloInverse(aDenominator);
while ( digits.size() <
final int digit = Math.floorMod(aNumerator * inverse, prime);
digits.addLast(digit);
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aNumerator -= digit * aDenominator;
if ( aNumerator
padWithZeros(digits);▼
} else {▼
// The denominator is not a power of a prime
int count = 0;
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}
}
}
}
* Return the sum of this p-adic number
*/
public Padic add(Padic aOther) {
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}
List<Integer> result = new ArrayList<Integer>(
// Adjust the digits so that the p-adic points are aligned
for ( int i = 0; i < -order + aOther.order; i++ ) {
aOther.digits.addFirst(0);
}
for ( int i = 0; i < -aOther.order + order; i++ ) {
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for ( int i = 0; i < Math.min(digits.size(), aOther.digits.size()); i++ ) {
final int sum = digits.get(i) + aOther.digits.get(i) + carry;
final int remainder = Math.floorMod(sum
carry = ( sum >= prime ) ? 1 : 0;
result.addLast(remainder);
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}
return new Padic(prime, result, allZeroDigits(result) ?
}
/**
* Return
*/
public
List<Integer> numbers = new ArrayList<Integer>(digits);
// Zero
if ( numbers.isEmpty() || allZeroDigits(numbers) ) {
return
}
// Positive integer
if ( order >= 0 && endsWith(numbers, 0) ) {
numbers.
}
return
}
// Negative integer
if ( order >= 0 && endsWith(numbers, prime - 1) ) {
numbers.removeLast();▼
▲ }
negateList(numbers);
return "-" + String.valueOf(convertToDecimal(numbers));▼
}
}
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sum = sum.add(self);
denominator += 1;
} while ( ! ( endsWith(sum.digits, 0)
final boolean negative = endsWith(sum.digits,
if ( negative ) {
negateList(sum.digits);
}
int numerator = negative ? -convertToDecimal(sum.digits) : convertToDecimal(sum.digits);
if ( order > 0 ) {
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}
}
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* Return a string representation of this p-adic.
*/
public String toString() {
List<Integer> numbers = new ArrayList<Integer>(digits);
Collections.reverse(numbers);
}▼
String numberString = numbers.stream().map(String::valueOf).collect(Collectors.joining());
StringBuilder builder = new StringBuilder(numberString);▼
▲ StringBuilder builder = new StringBuilder();
▲ for ( int i = digits.size() - 1; i >= 0; i-- ) {
}▼
if ( order >= 0 ) {
for ( int i = 0; i < order; i++ ) {
builder.append("0");
builder.deleteCharAt(0);▼
}
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} else {
builder.insert(builder.length() + order, ".");
while ( builder.toString().endsWith("0") ) {
}
}
return " ..." + builder.toString().substring(builder.length() - PRECISION - 1);
}
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prime = aPrime;
digits = new ArrayList<Integer>(aDigits);
order = aOrder;
}
/**
* Return the multiplicative inverse of the given decimal number modulo 'prime'.
*/
private int moduloInverse(int aNumber) {
int inverse = 1;
while ( Math.floorMod(
inverse += 1;
}
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*/
private void negateList(List<Integer> aDigits) {
aDigits.set(0, Math.floorMod(prime - aDigits.get(0), prime));
for ( int i = 1; i < aDigits.size(); i++ ) {
aDigits.set(i, prime - 1 - aDigits.get(i));
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int multiple = 1;
for ( int number : aNumbers ) {
decimal += number * multiple;
multiple *= prime;
}
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*/
private static void padWithZeros(List<Integer> aList) {
while ( aList.size() <
aList.addLast(0);
}
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return true;
▲ }
private static class Rational {
public Rational(int aNumerator, int aDenominator) {
if ( aDenominator < 0 ) {
numerator = -aNumerator;
denominator = -aDenominator;
numerator = aNumerator;
denominator = aDenominator;
}
if ( aNumerator == 0 ) {
denominator = 1;
}
final int gcd = gcd(numerator, denominator);
numerator /= gcd;
denominator /= gcd;
▲ }
public String toString() {
return numerator + " / " + denominator;
▲ }
private int gcd(int aOne, int aTwo) {
if ( aTwo == 0 ) {
return Math.abs(aOne);
}
return gcd(aTwo, Math.floorMod(aOne, aTwo));
▲ }
private int numerator;
private int denominator;
}
private List<Integer> digits;
private
private final int prime;
private static final int MAX_ORDER = 1_000;
private static final int PRECISION = 40;
private static final int
}
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7-adic numbers:
5 / 8 => ...
353 / 30809 => ...
sum => ...
Rational = 156869 / 246472
</pre>
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