Mercurial > dive4elements > river
view flys-artifacts/src/main/java/de/intevation/flys/utils/DoubleUtil.java @ 2768:1ddfb54e5db6
Added accidentally omitted file.
flys-artifacts/trunk@4507 c6561f87-3c4e-4783-a992-168aeb5c3f6f
author | Felix Wolfsteller <felix.wolfsteller@intevation.de> |
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date | Thu, 24 May 2012 13:54:37 +0000 |
parents | 0dd58ab7e118 |
children | 1ddbf66a2b0a |
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package de.intevation.flys.utils; import java.util.Arrays; import de.intevation.flys.artifacts.math.Linear; public class DoubleUtil { public static final double DEFAULT_STEP_PRECISION = 1e6; private DoubleUtil() { } public static final double [] explode(double from, double to, double step) { return explode(from, to, step, DEFAULT_STEP_PRECISION); } public static final double round(double x, double precision) { return Math.round(x * precision)/precision; } public static final double round(double x) { return Math.round(x * DEFAULT_STEP_PRECISION)/DEFAULT_STEP_PRECISION; } public static final double [] explode( double from, double to, double step, double precision ) { double lower = from; double diff = to - from; double tmp = diff / step; int num = (int)Math.abs(Math.ceil(tmp)) + 1; double [] values = new double[num]; if (from > to) { step = -step; } double max = Math.max(from, to); for (int idx = 0; idx < num; idx++) { if (lower > max) { return Arrays.copyOfRange(values, 0, idx); } values[idx] = round(lower, precision); lower += step; } return values; } public static final double interpolateSorted( double [] xs, double [] ys, double x ) { int lo = 0, hi = xs.length-1; int mid = -1; while (lo <= hi) { mid = (lo + hi) >> 1; double mx = xs[mid]; if (x < mx) hi = mid - 1; else if (x > mx) lo = mid + 1; else return ys[mid]; } if (mid < lo) { return lo >= xs.length ? Double.NaN : Linear.linear(x, xs[mid], xs[mid+1], ys[mid], ys[mid+1]); } return hi < 0 ? Double.NaN : Linear.linear(x, xs[mid-1], xs[mid], ys[mid-1], ys[mid]); } public static final boolean isIncreasing(double [] array) { int inc = 0; int dec = 0; int sweet = (array.length-1)/2; for (int i = 1; i < array.length; ++i) { if (array[i] > array[i-1]) { if (++inc > sweet) { return true; } } else if (++dec > sweet) { return false; } } return inc > sweet; } public static final double [] swap(double [] array) { int lo = 0; int hi = array.length-1; while (hi > lo) { double t = array[lo]; array[lo] = array[hi]; array[hi] = t; ++lo; --hi; } return array; } public static final double [] swapClone(double [] in) { double [] out = new double[in.length]; for (int j = out.length-1, i = 0; j >= 0;) { out[j--] = in[i++]; } return out; } public static final double [] sumDiffs(double [] in) { double [] out = new double[in.length]; for (int i = 1; i < out.length; ++i) { out[i] = out[i-1] + Math.abs(in[i-1] - in[i]); } return out; } public static final double [] fill(int N, double value) { double [] result = new double[N]; Arrays.fill(result, value); return result; } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :