overview of functions provided#

// namespaces

namespace conf;

// typedefs

typedef double rpc_;
typedef int ipc_;

// structs

struct nodend_control_type;
struct nodend_time_type;
struct nodend_inform_type;

// global functions

void nodend_initialize(
    void **data,
    struct nodend_control_type* control,
    ipc_ *status
);

void nodend_read_specfile(struct nodend_control_type* control, const char specfile[]);

void nodend_order(
    struct nodend_control_type* control,
    void **data,
    ipc_ *status,
    ipc_ n,
    ipc_ perm[],
    const char H_type[],
    ipc_ ne,
    const ipc_ A_row[],
    const ipc_ A_col[],
    const ipc_ A_ptr[]
);

void nodend_information(
    void **data,
    struct nodend_inform_type* inform,
    ipc_ *status
);

void nodend_terminate(
    void **data
);

typedefs#

typedef double rpc_

rpc_ is the real working precision used, but may be changed to float by defining the preprocessor variable REAL_32 or (if supported) to __real128 using the variable REAL_128.

typedef int ipc_

ipc_ is the default integer word length used, but may be changed to int64_t by defining the preprocessor variable INTEGER_64.

function and structure names#

The function and structure names described below are appropriate for the default real working precision (double) and integer word length (int32_t). To use the functions and structures with different precisions and integer word lengths, an additional suffix must be added to their names (and the arguments set accordingly). The appropriate suffices are:

_s for single precision (float) reals and standard 32-bit (int32_t) integers;

_q for quadruple precision (__real128) reals (if supported) and standard 32-bit (int32_t) integers;

_64 for standard precision (double) reals and 64-bit (int64_t) integers;

_s_64 for single precision (float) reals and 64-bit (int64_t) integers; and

_q_64 for quadruple precision (__real128) reals (if supported) and 64-bit (int64_t) integers.

Thus a call to nodend_initialize below will instead be

void nodend_initialize_s_64(void **data, struct nodend_control_type_s_64* control,
                         int64_t *status)

if single precision (float) reals and 64-bit (int64_t) integers are required. Thus it is possible to call functions for this package with more that one precision and/or integer word length at same time. An example is provided for the package expo, and the obvious modifications apply equally here.

function calls#

void nodend_initialize(
    void **data,
    struct nodend_control_type* control,
    ipc_ *status
)

Set default control values and initialize private data

Parameters:

data

holds private internal data

control

is a struct containing control information (see nodend_control_type)

status

is a scalar variable of type ipc_, that gives the exit status from the package. Possible values are (currently):

  • 0

    The initialization was successful.

 
void nodend_read_specfile(struct nodend_control_type* control, const char specfile[])

Read the content of a specification file, and assign values associated with given keywords to the corresponding control parameters. An in-depth discussion of specification files is available, and a detailed list of keywords with associated default values is provided in $GALAHAD/src/nodend/NODEND.template. See also Table 2.1 in the Fortran documentation provided in $GALAHAD/doc/nodend.pdf for a list of how these keywords relate to the components of the control structure.

Parameters:

control

is a struct containing control information (see nodend_control_type)

specfile

is a character string containing the name of the specification file

 
void nodend_order(
    struct nodend_control_type* control,
    void **data,
    ipc_ *status,
    ipc_ n,
    ipc_ perm[],
    const char H_type[],
    ipc_ ne,
    const ipc_ A_row[],
    const ipc_ A_col[],
    const ipc_ A_ptr[]
)

Find a row/colum permutation for sparse Cholesky-like factorization.

Parameters:

control

is a struct whose members provide control paramters for the remaining prcedures (see nodend_control_type)

data

holds private internal data

status

is a scalar variable of type ipc_, that gives the exit status from the package. Possible values are:

  • 1

    The import was successful, and the package is ready for the solve phase

  • -1

    An allocation error occurred. A message indicating the offending array is written on unit control.error, and the returned allocation status and a string containing the name of the offending array are held in inform.alloc_status and inform.bad_alloc respectively.

  • -2

    A deallocation error occurred. A message indicating the offending array is written on unit control.error and the returned allocation status and a string containing the name of the offending array are held in inform.alloc_status and inform.bad_alloc respectively.

  • -3

    The restriction n > 0 or requirement that type contains its relevant string ‘coordinate’ or ‘sparse_by_rows’ has been violated. One of the restrictions n \(> 0\), A.n \(> 0\) or A.ne \(< 0\), for co-ordinate entry, or requirements that A.type contain its relevant string ‘coordinate’ or ‘sparse_by_rows, and control.version in one of ‘4.0’, ‘5.1’ or ‘5.2’ has been violated.

  • -26

    The requested version of METIS is not available.

  • -57

    METIS has insufficient memory to continue.

  • -71

    An internal METIS error occurred.

n

is a scalar variable of type ipc_, that holds the number of variables.

perm

is a one-dimensional array of size n and type ipc_, that returns the computed permutation array, so that the perm[i]-th rows and columns in the permuted matrix \(P A P^T\) correspond to those labelled i in \(A\), 0 \(\leq\) i \(\leq\) n-1.

A_type

is a one-dimensional array of type char that specifies the symmetric storage scheme used for the Hessian. It should be one of ‘coordinate’ or ‘sparse_by_rows’; lower or upper case variants are allowed. If A_type is not one of the supported values, the identity permutation will be returned.

ne

is a scalar variable of type ipc_, that holds the number of entries in the lower triangular part of H in the sparse co-ordinate storage scheme. It need not be set for any of the other three schemes.

A_row

is a one-dimensional array of size ne and type ipc_, that holds the row indices of the lower triangular part of \(A\) in the sparse co-ordinate storage scheme. It need not be set for the other scheme, and in this case can be NULL

A_col

is a one-dimensional array of size ne and type ipc_, that holds the column indices of the lower triangular part of \(A\).

A_ptr

is a one-dimensional array of size n+1 and type ipc_, that holds the starting position of each row of the lower triangular part of \(A\), as well as the total number of entries, in the sparse row-wise storage scheme. It need not be set when the other scheme is used, and in this case can be NULL

 
void nodend_information(
    void **data,
    struct nodend_inform_type* inform,
    ipc_ *status
)

Provides output information

Parameters:

data

holds private internal data

inform

is a struct containing output information (see nodend_inform_type)

status

is a scalar variable of type ipc_, that gives the exit status from the package. Possible values are (currently):

  • 0

    The values were recorded successfully

 
void nodend_terminate(
    void **data
)

Deallocate all internal private storage

Parameters:

data

holds private internal data