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root / src / may / bits / VectorBits.java @ 595:3b1f2aa8d36b
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package may.bits; |
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public class VectorBits |
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{
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public static void checkLengths(double[] v1, double[] v2) { |
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if (v1.length != v2.length) {
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IllegalArgumentException e = new IllegalArgumentException |
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("Found vector of length " + v2.length +
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", but all so far in this arithmetic operation have had length " +
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v1.length); |
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throw e;
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} |
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} |
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public static double sum(double[] v) { |
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double tot = 0.0; |
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int len = v.length;
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for (int i = 0; i < len; ++i) { |
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tot += v[i]; |
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} |
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return tot;
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} |
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public static void multiplyBy(double[] out, double[] in) { |
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checkLengths(out, in); |
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for (int i = 0; i < in.length; ++i) { |
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out[i] *= in[i]; |
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} |
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} |
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public static void divideBy(double[] out, double[] in) { |
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checkLengths(out, in); |
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for (int i = 0; i < in.length; ++i) { |
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out[i] /= in[i]; |
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} |
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} |
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public static void addTo(double[] out, double[] in) { |
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checkLengths(out, in); |
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for (int i = 0; i < in.length; ++i) { |
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out[i] += in[i]; |
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} |
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} |
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public static void subtractFrom(double[] out, double[] in) { |
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checkLengths(out, in); |
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for (int i = 0; i < in.length; ++i) { |
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out[i] -= in[i]; |
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} |
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} |
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public static double[] scaled(double[] v, double factor) { |
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int len = v.length;
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double[] out = new double[v.length]; |
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for (int i = 0; i < len; ++i) { |
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out[i] = v[i] * factor; |
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} |
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return out;
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} |
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public static double euclideanDistance(double[] v1, double[] v2) { |
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checkLengths(v1, v2); |
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double sum = 0.0; |
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for (int i = 0; i < v1.length; ++i) { |
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double d = v1[i] - v2[i];
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sum += d * d; |
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} |
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return Math.sqrt(sum); |
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} |
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} |
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