/* nag_ode_bvp_coll_nlin_setup (d02tvc) Example Program.
*
* Copyright 2024 Numerical Algorithms Group.
*
* Mark 30.0, 2024.
*/
#include <math.h>
#include <nag.h>
#include <stdio.h>
typedef struct {
double beta0, eta, lambda, mu;
} func_data;
#ifdef __cplusplus
extern "C" {
#endif
static void NAG_CALL ffun(double x, const double y[], Integer neq,
const Integer m[], double f[], Nag_Comm *comm);
static void NAG_CALL fjac(double x, const double y[], Integer neq,
const Integer m[], double dfdy[], Nag_Comm *comm);
static void NAG_CALL gafun(const double ya[], Integer neq, const Integer m[],
Integer nlbc, double ga[], Nag_Comm *comm);
static void NAG_CALL gbfun(const double yb[], Integer neq, const Integer m[],
Integer nrbc, double gb[], Nag_Comm *comm);
static void NAG_CALL gajac(const double ya[], Integer neq, const Integer m[],
Integer nlbc, double dgady[], Nag_Comm *comm);
static void NAG_CALL gbjac(const double yb[], Integer neq, const Integer m[],
Integer nrbc, double dgbdy[], Nag_Comm *comm);
static void NAG_CALL guess(double x, Integer neq, const Integer m[], double y[],
double dym[], Nag_Comm *comm);
#ifdef __cplusplus
}
#endif
int main(void) {
/* Scalars */
Integer exit_status = 0, neq = 6, mmax = 1, nlbc = 3, nrbc = 3;
double dx, ermx, beta0, eta, lambda, mu;
Integer i, iermx, ijermx, j, licomm, lrcomm, mxmesh, ncol, nmesh;
/* Arrays */
static double ruser[7] = {-1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0};
double *mesh = 0, *rcomm = 0, *tols = 0, *y = 0;
double rdum[1];
Integer *ipmesh = 0, *icomm = 0, *m = 0;
Integer idum[2];
func_data fd;
/* Nag Types */
Nag_Comm comm;
NagError fail;
INIT_FAIL(fail);
printf("nag_ode_bvp_coll_nlin_setup (d02tvc) Example Program Results\n\n");
/* For communication with user-supplied functions: */
comm.user = ruser;
/* Skip heading in data file */
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%" NAG_IFMT "%" NAG_IFMT "%*[^\n] ", &ncol, &nmesh,
&mxmesh);
if (!(mesh = NAG_ALLOC(mxmesh, double)) || !(m = NAG_ALLOC(neq, Integer)) ||
!(tols = NAG_ALLOC(neq, double)) ||
!(y = NAG_ALLOC(neq * mmax, double)) ||
!(ipmesh = NAG_ALLOC(mxmesh, Integer))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
/* Set orders of equations */
for (i = 0; i < neq; i++) {
m[i] = 1;
}
scanf("%lf%lf%lf%lf%*[^\n] ", &beta0, &eta, &lambda, &mu);
for (i = 0; i < neq; i++) {
scanf("%lf", &tols[i]);
}
scanf("%*[^\n] ");
dx = 1.0 / (double)(nmesh - 1);
mesh[0] = 0.0;
for (i = 1; i < nmesh - 1; i++) {
mesh[i] = mesh[i - 1] + dx;
}
mesh[nmesh - 1] = 1.0;
ipmesh[0] = 1;
for (i = 1; i < nmesh - 1; i++) {
ipmesh[i] = 2;
}
ipmesh[nmesh - 1] = 1;
/* Set data required for the user-supplied functions */
fd.beta0 = beta0;
fd.eta = eta;
fd.lambda = lambda;
fd.mu = mu;
/* Associate the data structure with comm.p */
comm.p = (Pointer)&fd;
/* Communication space query to get size of rcomm and icomm
* by setting lrcomm=0 in call to
* nag_ode_bvp_coll_nlin_setup (d02tvc):
* Ordinary differential equations, general nonlinear boundary value problem,
* setup for nag_ode_bvp_coll_nlin_solve (d02tlc).
*/
nag_ode_bvp_coll_nlin_setup(neq, m, nlbc, nrbc, ncol, tols, mxmesh, nmesh,
mesh, ipmesh, rdum, 0, idum, 2, &fail);
if (fail.code == NE_NOERROR) {
lrcomm = idum[0];
licomm = idum[1];
if (!(rcomm = NAG_ALLOC(lrcomm, double)) ||
!(icomm = NAG_ALLOC(licomm, Integer))) {
printf("Allocation failure\n");
exit_status = -2;
goto END;
}
/* Initialize, again using nag_ode_bvp_coll_nlin_setup (d02tvc). */
nag_ode_bvp_coll_nlin_setup(neq, m, nlbc, nrbc, ncol, tols, mxmesh, nmesh,
mesh, ipmesh, rcomm, lrcomm, icomm, licomm,
&fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_ode_bvp_coll_nlin_setup (d02tvc).\n%s\n",
fail.message);
exit_status = 2;
goto END;
}
}
if (fail.code != NE_NOERROR) {
printf("Error from nag_ode_bvp_coll_nlin_setup (d02tvc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
/* Solve */
/* nag_ode_bvp_coll_nlin_solve (d02tlc).
* Ordinary differential equations, general nonlinear boundary value problem,
* collocation technique.
*/
nag_ode_bvp_coll_nlin_solve(ffun, fjac, gafun, gbfun, gajac, gbjac, guess,
rcomm, icomm, &comm, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_ode_bvp_coll_nlin_solve (d02tlc).\n%s\n",
fail.message);
exit_status = 3;
goto END;
}
/* Extract mesh. */
/* nag_ode_bvp_coll_nlin_diag (d02tzc).
* Ordinary differential equations, general nonlinear boundary value
* problem, diagnostics for nag_ode_bvp_coll_nlin_solve (d02tlc).
*/
nag_ode_bvp_coll_nlin_diag(mxmesh, &nmesh, mesh, ipmesh, &ermx, &iermx,
&ijermx, rcomm, icomm, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_ode_bvp_coll_nlin_diag (d02tzc).\n%s\n",
fail.message);
exit_status = 4;
goto END;
}
/* Print mesh statistics */
printf(" Used a mesh of %4" NAG_IFMT " points\n", nmesh);
printf(" Maximum error = %10.2e in interval %4" NAG_IFMT " for component ",
ermx, iermx);
printf("%4" NAG_IFMT " \n\n\n", ijermx);
printf(" Mesh points:\n");
for (i = 0; i < nmesh; i++) {
printf("%4" NAG_IFMT "(%1" NAG_IFMT ")", i + 1, ipmesh[i]);
printf("%7.4f%s", mesh[i], (i + 1) % 4 ? " " : "\n");
}
printf("\n");
/* Print solution on mesh. */
printf("\n Computed solution at mesh points\n");
printf(" x y1 y2 y3\n");
for (i = 0; i < nmesh; i++) {
/* nag_ode_bvp_coll_nlin_interp (d02tyc).
* Ordinary differential equations, general nonlinear boundary value
* problem, interpolation for nag_ode_bvp_coll_nlin_solve (d02tlc).
*/
nag_ode_bvp_coll_nlin_interp(mesh[i], y, neq, mmax, rcomm, icomm, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_ode_bvp_coll_nlin_interp (d02tyc).\n%s\n",
fail.message);
exit_status = 5;
goto END;
}
printf("%6.3f ", mesh[i]);
for (j = 0; j < 3; j++) {
printf("%11.3e", y[j]);
}
printf("\n");
}
END:
NAG_FREE(mesh);
NAG_FREE(m);
NAG_FREE(tols);
NAG_FREE(rcomm);
NAG_FREE(y);
NAG_FREE(ipmesh);
NAG_FREE(icomm);
return exit_status;
}
static void NAG_CALL ffun(double x, const double y[], Integer neq,
const Integer m[], double f[], Nag_Comm *comm) {
func_data *fd = (func_data *)comm->p;
double beta;
Integer i;
double one = 1.0;
double two = 2.0;
double zero = 0.0;
if (comm->user[0] == -1.0) {
printf("(User-supplied callback ffun, first invocation.)\n");
comm->user[0] = 0.0;
}
/* nag_math_pi (x01aac). */
beta = fd->beta0 * (one + cos(two * nag_math_pi * x));
f[0] = fd->mu - beta * y[0] * y[2];
f[1] = beta * y[0] * y[2] - y[1] / fd->lambda;
f[2] = y[1] / fd->lambda - y[2] / fd->eta;
for (i = 3; i < 6; i++) {
f[i] = zero;
}
}
static void NAG_CALL fjac(double x, const double y[], Integer neq,
const Integer m[], double dfdy[], Nag_Comm *comm) {
func_data *fd = (func_data *)comm->p;
double beta;
double one = 1.0;
double two = 2.0;
if (comm->user[1] == -1.0) {
printf("(User-supplied callback fjac, first invocation.)\n");
comm->user[1] = 0.0;
}
/* nag_math_pi (x01aac). */
beta = fd->beta0 * (one + cos(two * nag_math_pi * x));
dfdy[0 + 0 * neq] = -beta * y[2];
dfdy[0 + 2 * neq] = -beta * y[0];
dfdy[1 + 0 * neq] = beta * y[2];
dfdy[1 + 1 * neq] = -one / fd->lambda;
dfdy[1 + 2 * neq] = beta * y[0];
dfdy[2 + 1 * neq] = one / fd->lambda;
dfdy[2 + 2 * neq] = -one / fd->eta;
}
static void NAG_CALL gafun(const double ya[], Integer neq, const Integer m[],
Integer nlbc, double ga[], Nag_Comm *comm) {
if (comm->user[2] == -1.0) {
printf("(User-supplied callback gafun, first invocation.)\n");
comm->user[2] = 0.0;
}
ga[0] = ya[0] - ya[3];
ga[1] = ya[1] - ya[4];
ga[2] = ya[2] - ya[5];
}
static void NAG_CALL gbfun(const double yb[], Integer neq, const Integer m[],
Integer nrbc, double gb[], Nag_Comm *comm) {
if (comm->user[3] == -1.0) {
printf("(User-supplied callback gbfun, first invocation.)\n");
comm->user[3] = 0.0;
}
gb[0] = yb[0] - yb[3];
gb[1] = yb[1] - yb[4];
gb[2] = yb[2] - yb[5];
}
static void NAG_CALL gajac(const double ya[], Integer neq, const Integer m[],
Integer nlbc, double dgady[], Nag_Comm *comm) {
double one = 1.0;
if (comm->user[4] == -1.0) {
printf("(User-supplied callback gajac, first invocation.)\n");
comm->user[4] = 0.0;
}
dgady[0 + 0 * nlbc] = one;
dgady[0 + 3 * nlbc] = -one;
dgady[1 + 1 * nlbc] = one;
dgady[1 + 4 * nlbc] = -one;
dgady[2 + 2 * nlbc] = one;
dgady[2 + 5 * nlbc] = -one;
}
static void NAG_CALL gbjac(const double yb[], Integer neq, const Integer m[],
Integer nrbc, double dgbdy[], Nag_Comm *comm) {
double one = 1.0;
if (comm->user[5] == -1.0) {
printf("(User-supplied callback gbjac, first invocation.)\n");
comm->user[5] = 0.0;
}
dgbdy[0 + 0 * nrbc] = one;
dgbdy[0 + 3 * nrbc] = -one;
dgbdy[1 + 1 * nrbc] = one;
dgbdy[1 + 4 * nrbc] = -one;
dgbdy[2 + 2 * nrbc] = one;
dgbdy[2 + 5 * nrbc] = -one;
}
static void NAG_CALL guess(double x, Integer neq, const Integer m[], double y[],
double dym[], Nag_Comm *comm) {
Integer i;
if (comm->user[6] == -1.0) {
printf("(User-supplied callback guess, first invocation.)\n");
comm->user[6] = 0.0;
}
for (i = 0; i < neq; i++) {
y[i] = 1.0;
dym[i] = 0.0;
}
}