/* nag_dsbgvd (f08ucc) Example Program. * * Copyright 2011 Numerical Algorithms Group. * * Mark 23, 2011. */ #include #include #include #include #include int main(void) { /* Scalars */ Integer exit_status = 0, i, j, ka, kb, n, pdab, pdbb, pdz, zsize; /* Arrays */ double *ab = 0, *bb = 0, *w = 0, *z = 0; char nag_enum_arg[40]; /* Nag Types */ NagError fail; Nag_OrderType order; Nag_UploType uplo; Nag_JobType job; #ifdef NAG_COLUMN_MAJOR #define AB_UPPER(I, J) ab[(J-1)*pdab + ka + I - J] #define AB_LOWER(I, J) ab[(J-1)*pdab + I - J] #define BB_UPPER(I, J) bb[(J-1)*pdbb + kb + I - J] #define BB_LOWER(I, J) bb[(J-1)*pdbb + I - J] order = Nag_ColMajor; #else #define AB_UPPER(I, J) ab[(I-1)*pdab + J - I] #define AB_LOWER(I, J) ab[(I-1)*pdab + ka + J - I] #define BB_UPPER(I, J) bb[(I-1)*pdbb + J - I] #define BB_LOWER(I, J) bb[(I-1)*pdbb + kb + J - I] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_dsbgvd (f08ucc) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n]"); scanf("%ld%ld%ld%*[^\n]", &n, &ka, &kb); if (n < 0 || ka < kb || kb < 0) { printf("Invalid n, ka or kb\n"); exit_status = 1; goto END; } scanf(" %39s%*[^\n]", nag_enum_arg); /* nag_enum_name_to_value (x04nac). * Converts NAG enum member name to value */ uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg); scanf(" %39s%*[^\n]", nag_enum_arg); job = (Nag_JobType) nag_enum_name_to_value(nag_enum_arg); if (job==Nag_EigVals) { zsize = 1; pdz = 1; } else { zsize = n*n; pdz = n; } pdab = ka + 1; pdbb = kb + 1; /* Allocate memory */ if (!(ab = NAG_ALLOC((ka+1) * n, double)) || !(bb = NAG_ALLOC((kb+1) * n, double)) || !(z = NAG_ALLOC(zsize, double)) || !(w = NAG_ALLOC(n, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read the triangular parts of the matrices A and B from data file */ if (uplo == Nag_Upper) { for (i = 1; i <= n; ++i) for (j = i; j <= MIN(i+ka, n); ++j) scanf("%lf", &AB_UPPER(i, j)); scanf("%*[^\n]"); for (i = 1; i <= n; ++i) for (j = i; j <= MIN(i+kb, n); ++j) scanf("%lf", &BB_UPPER(i, j)); } else { for (i = 1; i <= n; ++i) for (j = MAX(1, i-ka); j <= i; ++j) scanf("%lf", &AB_LOWER(i, j)); scanf("%*[^\n]"); for (i = 1; i <= n; ++i) for (j = MAX(1, i-kb); j <= i; ++j) scanf("%lf", &BB_LOWER(i, j)); } scanf("%*[^\n]"); /* Solve the generalized symmetric band eigenvalue problem A*x = lambda*B*x * using nag_dsbgvd (f08ucc). */ nag_dsbgvd(order, job, uplo, n, ka, kb, ab, pdab, bb, pdbb, w, z, pdz, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dsbgvd (f08ucc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print eigensolution */ printf(" Eigenvalues\n "); for (j = 0; j < n; ++j) printf(" %9.4f%s", w[j], j%6 == 5?"\n":" "); printf("\n"); if (job==Nag_DoBoth) { /* nag_gen_real_mat_print (x04cac): Print Matrix of eigenvectors Z. */ printf("\n"); fflush(stdout); nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, z, pdz, "Eigenvectors (by Column)", 0, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_gen_real_mat_print (x04cac).\n%s\n", fail.message); exit_status = 1; } } END: NAG_FREE(ab); NAG_FREE(bb); NAG_FREE(z); NAG_FREE(w); return exit_status; }