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Posted to commits@commons.apache.org by er...@apache.org on 2020/04/07 17:23:43 UTC
[commons-math] 05/06: MATH-1530: Loop rewrite.
This is an automated email from the ASF dual-hosted git repository.
erans pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-math.git
commit 9c6ed8311fcb30518cc8935146d72a5b9126d41c
Author: Gilles Sadowski <gi...@gmail.com>
AuthorDate: Mon Apr 6 19:06:12 2020 +0200
MATH-1530: Loop rewrite.
---
.../analysis/interpolation/SplineInterpolator.java | 25 ++++++++++++++--------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/src/main/java/org/apache/commons/math4/analysis/interpolation/SplineInterpolator.java b/src/main/java/org/apache/commons/math4/analysis/interpolation/SplineInterpolator.java
index 8da99b8..b0c8c8b 100644
--- a/src/main/java/org/apache/commons/math4/analysis/interpolation/SplineInterpolator.java
+++ b/src/main/java/org/apache/commons/math4/analysis/interpolation/SplineInterpolator.java
@@ -90,15 +90,22 @@ public class SplineInterpolator implements UnivariateInterpolator {
final double[] mu = new double[n];
final double[] z = new double[n + 1];
double g = 0;
- for (int i = 1; i < n; i++) {
- final double xIp1 = x[i + 1];
- final double xIm1 = x[i - 1];
- final double hIm1 = h[i - 1];
- final double hI = h[i];
- g = 2d * (xIp1 - xIm1) - hIm1 * mu[i -1];
- mu[i] = hI / g;
- z[i] = (3d * (y[i + 1] * hIm1 - y[i] * (xIp1 - xIm1)+ y[i - 1] * hI) /
- (hIm1 * hI) - hIm1 * z[i - 1]) / g;
+ int indexM1 = 0;
+ int index = 1;
+ int indexP1 = 2;
+ while (index < n) {
+ final double xIp1 = x[indexP1];
+ final double xIm1 = x[indexM1];
+ final double hIm1 = h[indexM1];
+ final double hI = h[index];
+ g = 2d * (xIp1 - xIm1) - hIm1 * mu[indexM1];
+ mu[index] = hI / g;
+ z[index] = (3d * (y[indexP1] * hIm1 - y[index] * (xIp1 - xIm1)+ y[indexM1] * hI) /
+ (hIm1 * hI) - hIm1 * z[indexM1]) / g;
+
+ indexM1 = index;
+ index = indexP1;
+ indexP1 = indexP1 + 1;
}
// cubic spline coefficients -- b is linear, c quadratic, d is cubic (original y's are constants)