UpsilonNumworks/Upsilon
1
0
Fork 0
mirror of https://github.com/UpsilonNumworks/Upsilon.git synced 2026-03-28 18:20:14 +01:00
Code Issues Packages Projects Releases Wiki Activity

[poincare] Add comments to integral approximation for future

Browse Source 
improvements

Change-Id: I44131774674cb7db3c8c0450a29faa5a08120ae6
This commit is contained in:
Émilie Feral
2017-01-13 15:13:12 +01:00
parent d9877e6181
commit 5d746ff861
1 changed files with 12 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
poincare/src/integral.cpp
View File

@@ -26,10 +26,19 @@ Expression * Integral::cloneWithDifferentOperands(Expression** newOperands,
}
float Integral::approximate(Context& context) const {
/* We here use Gauss-Legendre quadrature with n = 5 */
/* We here use Gauss-Legendre quadrature with n = 5
* Gauss-Legendre abscissae and weights taken from
* http://www.holoborodko.com/pavel/numerical-methods/numerical-integration/*/
/* TODO: implement an adaptive quadrature version
* Use Gauss-Konrad quadrature (the one used in GNU scientific library)?
* QAGS and QAGI from netlib?
* Add to this version:
* - assess error
* - higher degree if error > threshold
* - find a way to reuse x and w ? Or useless, store all values ? */
XContext xContext = XContext(&context);
static float x[5]={0.1488743389f, 0.4333953941f, 0.6794095682f, 0.8650633666f, 0.9739065285f};
static float w[5]={0.2955242247f, 0.2692667193f, 0.2190863625f, 0.1494513491f, 0.0666713443f};
static float x[5]={0.1488743389816312108848260f, 0.4333953941292471907992659f, 0.6794095682990244062343274f, 0.8650633666889845107320967f, 0.9739065285171717200779640f};
static float w[5]={0.2955242247147528701738930f, 0.2692667193099963550912269f, 0.2190863625159820439955349f, 0.1494513491505805931457763f, 0.0666713443086881375935688f};
float a = m_args[1]->approximate(context);
float b = m_args[2]->approximate(context);
float xm = 0.5f*(a+b);