1a8de75f0Sjeremylt /// @file 252bfb9bbSJeremy L Thompson /// Test polynomial interpolation in 1D 352bfb9bbSJeremy L Thompson /// \test Test polynomial interpolation in 1D 4a8de75f0Sjeremylt #include <ceed.h> 5a8de75f0Sjeremylt #include <math.h> 6a8de75f0Sjeremylt 752bfb9bbSJeremy L Thompson #define ALEN(a) (sizeof(a) / sizeof((a)[0])) 852bfb9bbSJeremy L Thompson 952bfb9bbSJeremy L Thompson static CeedScalar PolyEval(CeedScalar x, CeedInt n, const CeedScalar *p) { 1052bfb9bbSJeremy L Thompson CeedScalar y = p[n-1]; 1152bfb9bbSJeremy L Thompson for (CeedInt i=n-2; i>=0; i--) y = y*x + p[i]; 1252bfb9bbSJeremy L Thompson return y; 13a8de75f0Sjeremylt } 14a8de75f0Sjeremylt 15a8de75f0Sjeremylt int main(int argc, char **argv) { 16a8de75f0Sjeremylt Ceed ceed; 1752bfb9bbSJeremy L Thompson CeedVector X, Xq, U, Uq; 1852bfb9bbSJeremy L Thompson CeedBasis bxl, bul, bxg, bug; 1952bfb9bbSJeremy L Thompson CeedInt Q = 6; 2052bfb9bbSJeremy L Thompson const CeedScalar p[6] = {1, 2, 3, 4, 5, 6}; // 1 + 2x + 3x^2 + ... 2152bfb9bbSJeremy L Thompson const CeedScalar *xq, *uuq; 2252bfb9bbSJeremy L Thompson CeedScalar x[2], uq[Q]; 23a8de75f0Sjeremylt 24a8de75f0Sjeremylt CeedInit(argv[1], &ceed); 25aedaa0e5Sjeremylt 2652bfb9bbSJeremy L Thompson CeedVectorCreate(ceed, 2, &X); 2752bfb9bbSJeremy L Thompson CeedVectorCreate(ceed, Q, &Xq); 2852bfb9bbSJeremy L Thompson CeedVectorSetValue(Xq, 0); 2952bfb9bbSJeremy L Thompson CeedVectorCreate(ceed, Q, &U); 3052bfb9bbSJeremy L Thompson CeedVectorSetValue(U, 0); 3152bfb9bbSJeremy L Thompson CeedVectorCreate(ceed, Q, &Uq); 32a8de75f0Sjeremylt 3352bfb9bbSJeremy L Thompson CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, 2, Q, CEED_GAUSS_LOBATTO, &bxl); 3452bfb9bbSJeremy L Thompson CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, Q, Q, CEED_GAUSS_LOBATTO, &bul); 35aedaa0e5Sjeremylt 3652bfb9bbSJeremy L Thompson for (int i = 0; i < 2; i++) 3752bfb9bbSJeremy L Thompson x[i] = CeedIntPow(-1, i+1); 3852bfb9bbSJeremy L Thompson CeedVectorSetArray(X, CEED_MEM_HOST, CEED_USE_POINTER, (CeedScalar *)&x); 39aedaa0e5Sjeremylt 4052bfb9bbSJeremy L Thompson CeedBasisApply(bxl, 1, CEED_NOTRANSPOSE, CEED_EVAL_INTERP, X, Xq); 41a8de75f0Sjeremylt 4252bfb9bbSJeremy L Thompson CeedVectorGetArrayRead(Xq, CEED_MEM_HOST, &xq); 4352bfb9bbSJeremy L Thompson for (CeedInt i=0; i<Q; i++) 4452bfb9bbSJeremy L Thompson uq[i] = PolyEval(xq[i], ALEN(p), p); 4552bfb9bbSJeremy L Thompson CeedVectorRestoreArrayRead(Xq, &xq); 4652bfb9bbSJeremy L Thompson CeedVectorSetArray(Uq, CEED_MEM_HOST, CEED_USE_POINTER, (CeedScalar *)&uq); 4752bfb9bbSJeremy L Thompson 4852bfb9bbSJeremy L Thompson // This operation is the identity because the quadrature is collocated 4952bfb9bbSJeremy L Thompson CeedBasisApply(bul, 1, CEED_TRANSPOSE, CEED_EVAL_INTERP, Uq, U); 5052bfb9bbSJeremy L Thompson 5152bfb9bbSJeremy L Thompson CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, 2, Q, CEED_GAUSS, &bxg); 5252bfb9bbSJeremy L Thompson CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, Q, Q, CEED_GAUSS, &bug); 5352bfb9bbSJeremy L Thompson 5452bfb9bbSJeremy L Thompson CeedBasisApply(bxg, 1, CEED_NOTRANSPOSE, CEED_EVAL_INTERP, X, Xq); 5552bfb9bbSJeremy L Thompson CeedBasisApply(bug, 1, CEED_NOTRANSPOSE, CEED_EVAL_INTERP, U, Uq); 5652bfb9bbSJeremy L Thompson 5752bfb9bbSJeremy L Thompson CeedVectorGetArrayRead(Xq, CEED_MEM_HOST, &xq); 5852bfb9bbSJeremy L Thompson CeedVectorGetArrayRead(Uq, CEED_MEM_HOST, &uuq); 5952bfb9bbSJeremy L Thompson for (CeedInt i=0; i<Q; i++) { 6052bfb9bbSJeremy L Thompson CeedScalar px = PolyEval(xq[i], ALEN(p), p); 61*166c82afSvaleriabarra if (fabs(uuq[i] - px) > 1E-14) 62a2546046Sjeremylt // LCOV_EXCL_START 6352bfb9bbSJeremy L Thompson printf("%f != %f=p(%f)\n", uuq[i], px, xq[i]); 64de996c55Sjeremylt // LCOV_EXCL_STOP 65a8de75f0Sjeremylt } 6652bfb9bbSJeremy L Thompson CeedVectorRestoreArrayRead(Xq, &xq); 6752bfb9bbSJeremy L Thompson CeedVectorRestoreArrayRead(Uq, &uuq); 68a8de75f0Sjeremylt 6952bfb9bbSJeremy L Thompson CeedVectorDestroy(&X); 7052bfb9bbSJeremy L Thompson CeedVectorDestroy(&Xq); 7152bfb9bbSJeremy L Thompson CeedVectorDestroy(&U); 7252bfb9bbSJeremy L Thompson CeedVectorDestroy(&Uq); 7352bfb9bbSJeremy L Thompson CeedBasisDestroy(&bxl); 7452bfb9bbSJeremy L Thompson CeedBasisDestroy(&bul); 7552bfb9bbSJeremy L Thompson CeedBasisDestroy(&bxg); 7652bfb9bbSJeremy L Thompson CeedBasisDestroy(&bug); 77a8de75f0Sjeremylt CeedDestroy(&ceed); 78a8de75f0Sjeremylt return 0; 79a8de75f0Sjeremylt } 80