diff options
Diffstat (limited to 'bcprov/src/main/java/org/bouncycastle/pqc/math/ntru/polynomial/BigDecimalPolynomial.java')
-rw-r--r-- | bcprov/src/main/java/org/bouncycastle/pqc/math/ntru/polynomial/BigDecimalPolynomial.java | 258 |
1 files changed, 0 insertions, 258 deletions
diff --git a/bcprov/src/main/java/org/bouncycastle/pqc/math/ntru/polynomial/BigDecimalPolynomial.java b/bcprov/src/main/java/org/bouncycastle/pqc/math/ntru/polynomial/BigDecimalPolynomial.java deleted file mode 100644 index 697f51a..0000000 --- a/bcprov/src/main/java/org/bouncycastle/pqc/math/ntru/polynomial/BigDecimalPolynomial.java +++ /dev/null @@ -1,258 +0,0 @@ -package org.bouncycastle.pqc.math.ntru.polynomial; - -import java.math.BigDecimal; - -/** - * A polynomial with {@link BigDecimal} coefficients. - * Some methods (like <code>add</code>) change the polynomial, others (like <code>mult</code>) do - * not but return the result as a new polynomial. - */ -public class BigDecimalPolynomial -{ - private static final BigDecimal ZERO = new BigDecimal("0"); - private static final BigDecimal ONE_HALF = new BigDecimal("0.5"); - - BigDecimal[] coeffs; - - /** - * Constructs a new polynomial with <code>N</code> coefficients initialized to 0. - * - * @param N the number of coefficients - */ - BigDecimalPolynomial(int N) - { - coeffs = new BigDecimal[N]; - for (int i = 0; i < N; i++) - { - coeffs[i] = ZERO; - } - } - - /** - * Constructs a new polynomial with a given set of coefficients. - * - * @param coeffs the coefficients - */ - BigDecimalPolynomial(BigDecimal[] coeffs) - { - this.coeffs = coeffs; - } - - /** - * Constructs a <code>BigDecimalPolynomial</code> from a <code>BigIntPolynomial</code>. The two polynomials are independent of each other. - * - * @param p the original polynomial - */ - public BigDecimalPolynomial(BigIntPolynomial p) - { - int N = p.coeffs.length; - coeffs = new BigDecimal[N]; - for (int i = 0; i < N; i++) - { - coeffs[i] = new BigDecimal(p.coeffs[i]); - } - } - - /** - * Divides all coefficients by 2. - */ - public void halve() - { - for (int i = 0; i < coeffs.length; i++) - { - coeffs[i] = coeffs[i].multiply(ONE_HALF); - } - } - - /** - * Multiplies the polynomial by another. Does not change this polynomial - * but returns the result as a new polynomial. - * - * @param poly2 the polynomial to multiply by - * @return a new polynomial - */ - public BigDecimalPolynomial mult(BigIntPolynomial poly2) - { - return mult(new BigDecimalPolynomial(poly2)); - } - - /** - * Multiplies the polynomial by another, taking the indices mod N. Does not - * change this polynomial but returns the result as a new polynomial. - * - * @param poly2 the polynomial to multiply by - * @return a new polynomial - */ - public BigDecimalPolynomial mult(BigDecimalPolynomial poly2) - { - int N = coeffs.length; - if (poly2.coeffs.length != N) - { - throw new IllegalArgumentException("Number of coefficients must be the same"); - } - - BigDecimalPolynomial c = multRecursive(poly2); - - if (c.coeffs.length > N) - { - for (int k = N; k < c.coeffs.length; k++) - { - c.coeffs[k - N] = c.coeffs[k - N].add(c.coeffs[k]); - } - c.coeffs = copyOf(c.coeffs, N); - } - return c; - } - - /** - * Karazuba multiplication - */ - private BigDecimalPolynomial multRecursive(BigDecimalPolynomial poly2) - { - BigDecimal[] a = coeffs; - BigDecimal[] b = poly2.coeffs; - - int n = poly2.coeffs.length; - if (n <= 1) - { - BigDecimal[] c = coeffs.clone(); - for (int i = 0; i < coeffs.length; i++) - { - c[i] = c[i].multiply(poly2.coeffs[0]); - } - return new BigDecimalPolynomial(c); - } - else - { - int n1 = n / 2; - - BigDecimalPolynomial a1 = new BigDecimalPolynomial(copyOf(a, n1)); - BigDecimalPolynomial a2 = new BigDecimalPolynomial(copyOfRange(a, n1, n)); - BigDecimalPolynomial b1 = new BigDecimalPolynomial(copyOf(b, n1)); - BigDecimalPolynomial b2 = new BigDecimalPolynomial(copyOfRange(b, n1, n)); - - BigDecimalPolynomial A = (BigDecimalPolynomial)a1.clone(); - A.add(a2); - BigDecimalPolynomial B = (BigDecimalPolynomial)b1.clone(); - B.add(b2); - - BigDecimalPolynomial c1 = a1.multRecursive(b1); - BigDecimalPolynomial c2 = a2.multRecursive(b2); - BigDecimalPolynomial c3 = A.multRecursive(B); - c3.sub(c1); - c3.sub(c2); - - BigDecimalPolynomial c = new BigDecimalPolynomial(2 * n - 1); - for (int i = 0; i < c1.coeffs.length; i++) - { - c.coeffs[i] = c1.coeffs[i]; - } - for (int i = 0; i < c3.coeffs.length; i++) - { - c.coeffs[n1 + i] = c.coeffs[n1 + i].add(c3.coeffs[i]); - } - for (int i = 0; i < c2.coeffs.length; i++) - { - c.coeffs[2 * n1 + i] = c.coeffs[2 * n1 + i].add(c2.coeffs[i]); - } - return c; - } - } - - /** - * Adds another polynomial which can have a different number of coefficients. - * - * @param b another polynomial - */ - public void add(BigDecimalPolynomial b) - { - if (b.coeffs.length > coeffs.length) - { - int N = coeffs.length; - coeffs = copyOf(coeffs, b.coeffs.length); - for (int i = N; i < coeffs.length; i++) - { - coeffs[i] = ZERO; - } - } - for (int i = 0; i < b.coeffs.length; i++) - { - coeffs[i] = coeffs[i].add(b.coeffs[i]); - } - } - - /** - * Subtracts another polynomial which can have a different number of coefficients. - * - * @param b - */ - void sub(BigDecimalPolynomial b) - { - if (b.coeffs.length > coeffs.length) - { - int N = coeffs.length; - coeffs = copyOf(coeffs, b.coeffs.length); - for (int i = N; i < coeffs.length; i++) - { - coeffs[i] = ZERO; - } - } - for (int i = 0; i < b.coeffs.length; i++) - { - coeffs[i] = coeffs[i].subtract(b.coeffs[i]); - } - } - - /** - * Rounds all coefficients to the nearest integer. - * - * @return a new polynomial with <code>BigInteger</code> coefficients - */ - public BigIntPolynomial round() - { - int N = coeffs.length; - BigIntPolynomial p = new BigIntPolynomial(N); - for (int i = 0; i < N; i++) - { - p.coeffs[i] = coeffs[i].setScale(0, BigDecimal.ROUND_HALF_EVEN).toBigInteger(); - } - return p; - } - - /** - * Makes a copy of the polynomial that is independent of the original. - */ - public Object clone() - { - return new BigDecimalPolynomial(coeffs.clone()); - } - - private BigDecimal[] copyOf(BigDecimal[] a, int length) - { - BigDecimal[] tmp = new BigDecimal[length]; - - System.arraycopy(a, 0, tmp, 0, a.length < length ? a.length : length); - - return tmp; - } - - private BigDecimal[] copyOfRange(BigDecimal[] a, int from, int to) - { - int newLength = to - from; - BigDecimal[] tmp = new BigDecimal[to - from]; - - System.arraycopy(a, from, tmp, 0, (a.length - from) < newLength ? (a.length - from) : newLength); - - return tmp; - } - - public BigDecimal[] getCoeffs() - { - BigDecimal[] tmp = new BigDecimal[coeffs.length]; - - System.arraycopy(coeffs, 0, tmp, 0, coeffs.length); - - return tmp; - } - -} |