void tangential_arc(const Point &p0, const Point &p1, const Point &v0, Point &c, int &dir)
{
geoff_geometry::Point gp0(p0.x, p0.y);
geoff_geometry::Point gp1(p1.x, p1.y);
geoff_geometry::Vector2d gv0(v0.x, v0.y);
geoff_geometry::Point gc;
geoff_geometry::tangential_arc(gp0, gp1, gv0, gc, dir);
c = Point(gc.x, gc.y);
}
float cal_obj_derr_illum_grad(const FwiParams ¶ms,
float *derr, /* output */
float *illum, /* output */
float *g1, /* output */
const float *wlt,
const float *dobs,
const EnquistAbc2d &fmMethod,
const ShotPosition &allSrcPos,
const ShotPosition &allGeoPos)
{
int nt = params.nt;
int nz = params.nz;
int nx = params.nx;
int ng = params.ng;
int ns = params.ns;
std::vector<float> bndr = fmMethod.initBndryVector(nt);
std::vector<float> dcal(ng, 0); /* calculated/synthetic seismic data */
std::vector<float> sp0(nz * nx); /* source wavefield p0 */
std::vector<float> sp1(nz * nx); /* source wavefield p1 */
std::vector<float> sp2(nz * nx); /* source wavefield p2 */
std::vector<float> gp0(nz * nx); /* geophone/receiver wavefield p0 */
std::vector<float> gp1(nz * nx); /* geophone/receiver wavefield p1 */
std::vector<float> gp2(nz * nx); /* geophone/receiver wavefield p2 */
std::vector<float> lap(nz * nx); /* laplace of the source wavefield */
for (int is = 0; is < ns; is++) {
std::fill(sp0.begin(), sp0.end(), 0);
std::fill(sp1.begin(), sp1.end(), 0);
ShotPosition curSrcPos = allSrcPos.clip(is);
for (int it = 0; it < nt; it++) {
fmMethod.addSource(&sp1[0], &wlt[it], curSrcPos);
fmMethod.stepForward(&sp0[0], &sp1[0], &sp2[0]);
// cycle swap
cycleSwap(sp0, sp1, sp2);
fmMethod.writeBndry(&bndr[0], &sp0[0], it);
fmMethod.recordSeis(&dcal[0], &sp0[0], allGeoPos);
cal_residuals(&dcal[0], &dobs[is * nt * ng + it * ng], &derr[is * ng * nt + it * ng], ng);
}
std::swap(sp0, sp1);
std::fill(gp0.begin(), gp0.end(), 0);
std::fill(gp1.begin(), gp1.end(), 0);
for (int it = nt - 1; it > -1; it--) {
/// backward propagate source wavefield
fmMethod.readBndry(&bndr[0], &sp1[0], it);
fmMethod.stepBackward(illum, &lap[0], &sp0[0], &sp1[0], &sp2[0]);
fmMethod.subSource(&sp1[0], &wlt[it], curSrcPos);
/// forward propagate geophone wavefield
fmMethod.addSource(&gp1[0], &derr[is * ng * nt + it * ng], allGeoPos);
fmMethod.stepForward(&gp0[0], &gp1[0], &gp2[0]);
/// calculate gradient
cal_gradient(&g1[0], &lap[0], &gp1[0], nz, nx);
cycleSwap(sp0, sp1, sp2);
cycleSwap(gp0, gp1, gp2);
}
} /// output: derr, g1, illum
float obj = cal_objective(&derr[0], ng * nt * ns);
return obj;
}
