// Gmsh - Copyright (C) 1997-2019 C. Geuzaine, J.-F. Remacle // // See the LICENSE.txt file for license information. Please report all // issues on https://gitlab.onelab.info/gmsh/gmsh/issues. #include "approximationError.h" #include "MElement.h" double approximationError(simpleFunction<double> &f, MElement *element) { std::vector<double> VALS(element->getNumVertices()); for(std::size_t i = 0; i < element->getNumVertices(); i++) { MVertex *v = element->getVertex(i); VALS[i] = f(v->x(), v->y(), v->z()); } int npts; IntPt *pts; element->getIntegrationPoints(2 * element->getPolynomialOrder() + 2, &npts, &pts); double errSqr = 0.0; for(int k = 0; k < npts; k++) { const double u = pts[k].pt[0]; const double v = pts[k].pt[1]; const double w = pts[k].pt[2]; SPoint3 p; element->pnt(u, v, w, p); const double Jac = element->getJacobianDeterminant(u, v, w); const double C = element->interpolate(&VALS[0], u, v, w); const double F = f(p.x(), p.y(), p.z()); errSqr += pts[k].weight * Jac * std::pow(C - F, 2); } return std::sqrt(errSqr); }