Mercurial > dive4elements > river
comparison flys-artifacts/src/main/java/de/intevation/flys/exports/fixings/FixATWriter.java @ 3643:171db4d5d3cb
FixA: AT export: prevent some numerical problems with steep functions around zero.
flys-artifacts/trunk@5363 c6561f87-3c4e-4783-a992-168aeb5c3f6f
| author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
|---|---|
| date | Wed, 05 Sep 2012 08:38:12 +0000 |
| parents | 83c0735092a3 |
| children | 8bbb9e173297 |
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| 3642:83c0735092a3 | 3643:171db4d5d3cb |
|---|---|
| 30 | 30 |
| 31 public static final String [] Q_MAX_COLUMN = new String [] { "max_q" }; | 31 public static final String [] Q_MAX_COLUMN = new String [] { "max_q" }; |
| 32 | 32 |
| 33 private static final int MAX_ITERATIONS = 10000; | 33 private static final int MAX_ITERATIONS = 10000; |
| 34 private static final double EPSILON = 1e-8; | 34 private static final double EPSILON = 1e-8; |
| 35 private static final double MIN_Q = 1e-4; | |
| 35 | 36 |
| 36 protected Function function; | 37 protected Function function; |
| 37 protected Parameters parameters; | 38 protected Parameters parameters; |
| 38 | 39 |
| 39 public FixATWriter() { | 40 public FixATWriter() { |
| 164 | 165 |
| 165 for (int i = 0; i < MAX_ITERATIONS; ++i) { | 166 for (int i = 0; i < MAX_ITERATIONS; ++i) { |
| 166 double w = lastW - stepWidth; | 167 double w = lastW - stepWidth; |
| 167 double q = function.value(w); | 168 double q = function.value(w); |
| 168 | 169 |
| 169 if (Double.isNaN(q) || q > lastQ || q < 0d) { | 170 if (Double.isNaN(q) || q > lastQ || q < MIN_Q) { |
| 170 if (stepWidth < EPSILON) { | 171 if (stepWidth < EPSILON) { |
| 171 break; | 172 break; |
| 172 } | 173 } |
| 173 stepWidth *= 0.5d; | 174 stepWidth *= 0.5d; |
| 174 continue; | 175 continue; |