/* nag_zhbevd (f08hqc) Example Program. * * Copyright 2001 Numerical Algorithms Group. * * Mark 7, 2001. */ #include #include #include #include #include int main(void) { /* Scalars */ Integer i, j, k, kd, n, pdab, pdz, w_len; Integer exit_status=0; NagError fail; Nag_JobType job; Nag_UploType uplo; Nag_OrderType order; /* Arrays */ char uplo_char[2], job_char[2]; Complex *ab=0, *z=0; double *w=0; #ifdef NAG_COLUMN_MAJOR #define AB_UPPER(I,J) ab[(J-1)*pdab + k + I - J - 1] #define AB_LOWER(I,J) ab[(J-1)*pdab + 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 + k + J - I - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); Vprintf("nag_zhbevd (f08hqc) Example Program Results\n\n"); /* Skip heading in data file */ Vscanf("%*[^\n] "); Vscanf("%ld%ld%*[^\n] ", &n, &kd); pdab = kd + 1; pdz = n; w_len = n; /* Allocate memory */ if ( !(ab = NAG_ALLOC(pdab * n, Complex)) || !(w = NAG_ALLOC(w_len, double)) || !(z = NAG_ALLOC(n * n, Complex)) ) { Vprintf("Allocation failure\n"); exit_status = -1; goto END; } /* Read whether Upper or Lower part of A is stored */ Vscanf(" ' %1s '%*[^\n] ", uplo_char); if (*(unsigned char *)uplo_char == 'L') uplo = Nag_Lower; else if (*(unsigned char *)uplo_char == 'U') uplo = Nag_Upper; else { Vprintf("Unrecognised character for Nag_UploType type\n"); exit_status = -1; goto END; } /* Read A from data file */ k = kd + 1; if (uplo == Nag_Upper) { for (i = 1; i <= n; ++i) { for (j = i; j <= MIN(i+kd,n); ++j) { Vscanf(" ( %lf , %lf )", &AB_UPPER(i,j).re, &AB_UPPER(i,j).im); } } Vscanf("%*[^\n] "); } else { for (i = 1; i <= n; ++i) { for (j = MAX(1,i-kd); j <= i; ++j) { Vscanf(" ( %lf , %lf )", &AB_LOWER(i,j).re, &AB_LOWER(i,j).im); } } Vscanf("%*[^\n] "); } /* Read type of job to be performed */ Vscanf(" ' %1s '%*[^\n] ", job_char); if (*(unsigned char *)job_char == 'V') job = Nag_EigVecs; else job = Nag_DoNothing; /* Calculate all the eigenvalues and eigenvectors of A */ /* nag_zhbevd (f08hqc). * All eigenvalues and optionally all eigenvectors of * complex Hermitian band matrix (divide-and-conquer) */ nag_zhbevd(order, job, uplo, n, kd, ab, pdab, w, z, pdz, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_zhbevd (f08hqc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print eigenvalues and eigenvectors */ Vprintf(" Eigenvalues\n"); for (i = 0; i < n; ++i) Vprintf(" %5ld %8.4f\n", i+1, w[i]); Vprintf("\n"); /* nag_gen_complx_mat_print_comp (x04dbc). * Print complex general matrix (comprehensive) */ nag_gen_complx_mat_print_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, z, pdz, Nag_AboveForm, "%7.4f", "Eigenvectors", Nag_IntegerLabels, 0, Nag_IntegerLabels, 0, 80, 0, 0, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n", fail.message); exit_status = 1; goto END; } END: if (ab) NAG_FREE(ab); if (w) NAG_FREE(w); if (z) NAG_FREE(z); return exit_status; }