private GaussLegendre2D(int orderXi, int orderEta)
{
GaussLegendre1D quadratureXi = GaussLegendre1D.GetQuadratureWithOrder(orderXi);
GaussLegendre1D quadratureEta = GaussLegendre1D.GetQuadratureWithOrder(orderEta);
var points2D = new List <GaussPoint>();
// Combine the integration rules of each axis. The order is Xi minor - Eta major
// WARNING: Do not change their order. Other classes, such as ExtrapolationGaussLegendre2x2 depend on it.
foreach (var pointEta in quadratureEta.IntegrationPoints)
{
foreach (var pointXi in quadratureXi.IntegrationPoints)
{
points2D.Add(new GaussPoint(pointXi.Xi, pointEta.Xi, pointXi.Weight * pointEta.Weight));
}
}
this.IntegrationPoints = points2D;
}
static GaussLegendre1D()
{
// In practice having an initial capacity of 10 is more than enough.
quadratures = new Dictionary <int, GaussLegendre1D>(10);
// Order 1
quadratures[1] = new GaussLegendre1D(new GaussPoint(0.0, weight: 2.0));
// Order 2
quadratures[2] = new GaussLegendre1D(
new GaussPoint(-0.5773502691896257645091488, 1.0),
new GaussPoint(+0.5773502691896257645091488, 1.0));
// Order 3
quadratures[3] = new GaussLegendre1D(
new GaussPoint(-0.7745966692414833770358531, 0.5555555555555555555555556),
new GaussPoint(0.0, 0.8888888888888888888888889),
new GaussPoint(+0.7745966692414833770358531, 0.5555555555555555555555556));
// Order 4
quadratures[4] = new GaussLegendre1D(
new GaussPoint(-0.8611363115940525752239465, 0.3478548451374538573730639),
new GaussPoint(-0.3399810435848562648026658, 0.6521451548625461426269361),
new GaussPoint(+0.3399810435848562648026658, 0.6521451548625461426269361),
new GaussPoint(+0.8611363115940525752239465, 0.3478548451374538573730639));
// Order 5
quadratures[5] = new GaussLegendre1D(
new GaussPoint(-0.9061798459386639927976269, 0.2369268850561890875142640),
new GaussPoint(-0.5384693101056830910363144, 0.4786286704993664680412915),
new GaussPoint(0, 0.5688888888888888888888889),
new GaussPoint(+0.5384693101056830910363144, 0.4786286704993664680412915),
new GaussPoint(+0.9061798459386639927976269, 0.2369268850561890875142640));
// Order 6
quadratures[6] = new GaussLegendre1D(
new GaussPoint(-0.9324695142031520278123016, 0.1713244923791703450402961),
new GaussPoint(-0.6612093864662645136613996, 0.3607615730481386075698335),
new GaussPoint(-0.2386191860831969086305017, 0.4679139345726910473898703),
new GaussPoint(+0.2386191860831969086305017, 0.4679139345726910473898703),
new GaussPoint(+0.6612093864662645136613996, 0.3607615730481386075698335),
new GaussPoint(+0.9324695142031520278123016, 0.1713244923791703450402961));
// Order 7
quadratures[7] = new GaussLegendre1D(
new GaussPoint(-0.9491079123427585245261897, 0.1294849661688696932706114),
new GaussPoint(-0.7415311855993944398638648, 0.2797053914892766679014678),
new GaussPoint(-0.4058451513773971669066064, 0.3818300505051189449503698),
new GaussPoint(0.0, 0.4179591836734693877551020),
new GaussPoint(+0.4058451513773971669066064, 0.3818300505051189449503698),
new GaussPoint(+0.7415311855993944398638648, 0.2797053914892766679014678),
new GaussPoint(+0.9491079123427585245261897, 0.1294849661688696932706114));
// Order 8
quadratures[8] = new GaussLegendre1D(
new GaussPoint(-0.9602898564975362316835609, 0.1012285362903762591525314),
new GaussPoint(-0.7966664774136267395915539, 0.2223810344533744705443560),
new GaussPoint(-0.5255324099163289858177390, 0.3137066458778872873379622),
new GaussPoint(-0.1834346424956498049394761, 0.3626837833783619829651504),
new GaussPoint(+0.1834346424956498049394761, 0.3626837833783619829651504),
new GaussPoint(+0.5255324099163289858177390, 0.3137066458778872873379622),
new GaussPoint(+0.7966664774136267395915539, 0.2223810344533744705443560),
new GaussPoint(+0.9602898564975362316835609, 0.1012285362903762591525314));
// Order 9
quadratures[9] = new GaussLegendre1D(
new GaussPoint(-0.9681602395076260898355762, 0.0812743883615744119718922),
new GaussPoint(-0.8360311073266357942994298, 0.1806481606948574040584720),
new GaussPoint(-0.6133714327005903973087020, 0.2606106964029354623187429),
new GaussPoint(-0.3242534234038089290385380, 0.3123470770400028400686304),
new GaussPoint(0, 0.3302393550012597631645251),
new GaussPoint(+0.3242534234038089290385380, 0.3123470770400028400686304),
new GaussPoint(+0.6133714327005903973087020, 0.2606106964029354623187429),
new GaussPoint(+0.8360311073266357942994298, 0.1806481606948574040584720),
new GaussPoint(+0.9681602395076260898355762, 0.0812743883615744119718922));
// Order 10
quadratures[10] = new GaussLegendre1D(
new GaussPoint(-0.9739065285171717200779640, 0.0666713443086881375935688),
new GaussPoint(-0.8650633666889845107320967, 0.1494513491505805931457763),
new GaussPoint(-0.6794095682990244062343274, 0.2190863625159820439955349),
new GaussPoint(-0.1488743389816312108848260, 0.2955242247147528701738930),
new GaussPoint(-0.4333953941292471907992659, 0.2692667193099963550912269),
new GaussPoint(+0.1488743389816312108848260, 0.2955242247147528701738930),
new GaussPoint(+0.4333953941292471907992659, 0.2692667193099963550912269),
new GaussPoint(+0.6794095682990244062343274, 0.2190863625159820439955349),
new GaussPoint(+0.8650633666889845107320967, 0.1494513491505805931457763),
new GaussPoint(+0.9739065285171717200779640, 0.0666713443086881375935688));
}