gltr_control_type structure

#include <galahad_gltr.h>

struct gltr_control_type {
    // fields

    bool f_indexing;
    ipc_ error;
    ipc_ out;
    ipc_ print_level;
    ipc_ itmax;
    ipc_ Lanczos_itmax;
    ipc_ extra_vectors;
    ipc_ ritz_printout_device;
    rpc_ stop_relative;
    rpc_ stop_absolute;
    rpc_ fraction_opt;
    rpc_ f_min;
    rpc_ rminvr_zero;
    rpc_ f_0;
    bool unitm;
    bool steihaug_toint;
    bool boundary;
    bool equality_problem;
    bool space_critical;
    bool deallocate_error_fatal;
    bool print_ritz_values;
    char ritz_file_name[31];
    char prefix[31];
};

detailed documentation

control derived type as a C struct

components

bool f_indexing

use C or Fortran sparse matrix indexing

ipc_ error

error and warning diagnostics occur on stream error

ipc_ out

general output occurs on stream out

ipc_ print_level

the level of output required is specified by print_level

ipc_ itmax

the maximum number of iterations allowed (-ve = no bound)

ipc_ Lanczos_itmax

the maximum number of iterations allowed once the boundary has been encountered (-ve = no bound)

ipc_ extra_vectors

the number of extra work vectors of length n used

ipc_ ritz_printout_device

the unit number for writing debug Ritz values

rpc_ stop_relative

the iteration stops successfully when the gradient in the M(inverse) nor is smaller than max( stop_relative * initial M(inverse) gradient norm, stop_absolute )

rpc_ stop_absolute

see stop_relative

rpc_ fraction_opt

an estimate of the solution that gives at least .fraction_opt times the optimal objective value will be found

rpc_ f_min

the iteration stops if the objective-function value is lower than f_min

rpc_ rminvr_zero

the smallest value that the square of the M norm of the gradient of the the objective may be before it is considered to be zero

rpc_ f_0

the constant term, \(f_0\), in the objective function

bool unitm

is \(M\) the identity matrix ?

bool steihaug_toint

should the iteration stop when the Trust-region is first encountered ?

bool boundary

is the solution thought to lie on the constraint boundary ?

bool equality_problem

is the solution required to lie on the constraint boundary ?

bool space_critical

if .space_critical true, every effort will be made to use as little space as possible. This may result in longer computation time

bool deallocate_error_fatal

if .deallocate_error_fatal is true, any array/pointer deallocation error will terminate execution. Otherwise, computation will continue

bool print_ritz_values

should the Ritz values be written to the debug stream?

char ritz_file_name[31]

name of debug file containing the Ritz values

char prefix[31]

all output lines will be prefixed by .prefix(2:LEN(TRIM(.prefix))-1) where .prefix contains the required string enclosed in quotes, e.g. “string” or ‘string’