Mercurial > dive4elements > river
comparison flys-artifacts/src/main/java/de/intevation/flys/utils/DoubleUtil.java @ 1671:da872168a899
Added code to interpolate double values in a sorted array
flys-artifacts/trunk@2883 c6561f87-3c4e-4783-a992-168aeb5c3f6f
| author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
|---|---|
| date | Tue, 04 Oct 2011 15:23:31 +0000 |
| parents | 09c1292cf36d |
| children | 0b6dac664bbb |
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| 1670:fc9719cddbc6 | 1671:da872168a899 |
|---|---|
| 1 package de.intevation.flys.utils; | 1 package de.intevation.flys.utils; |
| 2 | 2 |
| 3 import java.util.Arrays; | 3 import java.util.Arrays; |
| 4 | |
| 5 import de.intevation.flys.artifacts.math.Linear; | |
| 4 | 6 |
| 5 | 7 |
| 6 public class DoubleUtil | 8 public class DoubleUtil |
| 7 { | 9 { |
| 8 public static final double DEFAULT_STEP_PRECISION = 1e6; | 10 public static final double DEFAULT_STEP_PRECISION = 1e6; |
| 51 lower += step; | 53 lower += step; |
| 52 } | 54 } |
| 53 | 55 |
| 54 return values; | 56 return values; |
| 55 } | 57 } |
| 58 | |
| 59 public static final double interpolateSorted( | |
| 60 double [] xs, | |
| 61 double [] ys, | |
| 62 double x | |
| 63 ) { | |
| 64 int lo = 0, hi = xs.length-1; | |
| 65 | |
| 66 int mid = -1; | |
| 67 | |
| 68 while (lo <= hi) { | |
| 69 mid = (lo + hi) >> 1; | |
| 70 double mx = xs[mid]; | |
| 71 if (x < mx) hi = mid - 1; | |
| 72 else if (x > mx) lo = mid + 1; | |
| 73 else return ys[mid]; | |
| 74 } | |
| 75 if (mid < lo) { | |
| 76 return lo >= xs.length | |
| 77 ? Double.NaN | |
| 78 : Linear.linear(x, xs[mid], xs[mid+1], ys[mid], ys[mid+1]); | |
| 79 } | |
| 80 return hi < 0 | |
| 81 ? Double.NaN | |
| 82 : Linear.linear(x, xs[mid-1], xs[mid], ys[mid-1], ys[mid]); | |
| 83 } | |
| 56 } | 84 } |
| 57 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 : | 85 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 : |