overview of functions provided#

// namespaces

namespace conf;

// typedefs

typedef float spc_;
typedef double rpc_;
typedef int ipc_;

// structs

struct psls_control_type;
struct psls_inform_type;
struct psls_time_type;

// global functions

void psls_initialize(
    void **data,
    struct psls_control_type* control,
    ipc_ *status
);

void psls_read_specfile(
    struct psls_control_type* control,
    const char specfile[]
);

void psls_import(
    struct psls_control_type* control,
    void **data,
    ipc_ *status,
    ipc_ n,
    const char type[],
    ipc_ ne,
    const ipc_ row[],
    const ipc_ col[],
    const ipc_ ptr[]
);

void psls_reset_control(
    struct psls_control_type* control,
    void **data,
    ipc_ *status
);

void psls_form_preconditioner(
    void **data,
    ipc_ *status,
    ipc_ ne,
    const rpc_ val[]
);

void psls_form_subset_preconditioner(
    void **data,
    ipc_ *status,
    ipc_ ne,
    const rpc_ val[],
    ipc_ n_sub,
    const ipc_ sub[]
);

void psls_update_preconditioner(
    void **data,
    ipc_ *status,
    ipc_ ne,
    const rpc_ val[],
    ipc_ n_del,
    const ipc_ del[]
);

void psls_apply_preconditioner(void **data, ipc_ *status, ipc_ n, rpc_ sol[]);
void psls_information(void **data, struct psls_inform_type* inform, ipc_ *status);

void psls_terminate(
    void **data,
    struct psls_control_type* control,
    struct psls_inform_type* inform
);

typedefs#

typedef float spc_

spc_ is real single precision

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 calls#

void psls_initialize(
    void **data,
    struct psls_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 psls_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 psls_read_specfile(
    struct psls_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/psls/PSLS.template. See also Table 2.1 in the Fortran documentation provided in $GALAHAD/doc/psls.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 psls_control_type)
specfile	is a character string containing the name of the specification file

void psls_import(
    struct psls_control_type* control,
    void **data,
    ipc_ *status,
    ipc_ n,
    const char type[],
    ipc_ ne,
    const ipc_ row[],
    const ipc_ col[],
    const ipc_ ptr[]
)

Import structural matrix data into internal storage prior to solution.

Parameters:

control	is a struct whose members provide control paramters for the remaining prcedures (see psls_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 ‘dense’, ‘coordinate’, ‘sparse_by_rows’ or ‘diagonal’ has been violated.
n	is a scalar variable of type ipc_, that holds the number of rows in the symmetric matrix $A$.
type	is a one-dimensional array of type char that specifies the symmetric storage scheme used for the matrix $A$. It should be one of ‘coordinate’, ‘sparse_by_rows’ or ‘dense’; lower or upper case variants are allowed.
ne	is a scalar variable of type ipc_, that holds the number of entries in the lower triangular part of $A$ in the sparse co-ordinate storage scheme. It need not be set for any of the other schemes.
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 any of the other three schemes, and in this case can be NULL.
col	is a one-dimensional array of size ne and type ipc_, that holds the column indices of the lower triangular part of $A$ in either the sparse co-ordinate, or the sparse row-wise storage scheme. It need not be set when the dense storage scheme is used, and in this case can be NULL.
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 schemes are used, and in this case can be NULL.

void psls_reset_control(
    struct psls_control_type* control,
    void **data,
    ipc_ *status
)

Reset control parameters after import if required.

Parameters:

control

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

void psls_form_preconditioner(
    void **data,
    ipc_ *status,
    ipc_ ne,
    const rpc_ val[]
)

Form and factorize a preconditioner $P$ of the matrix $A$.

Parameters:

data	holds private internal data
status	is a scalar variable of type ipc_, that gives the exit status from the package. Possible values are: 0 The factors were generated successfully. -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. -26 The requested solver is not available. -29 This option is not available with this solver.
ne	is a scalar variable of type ipc_, that holds the number of entries in the lower triangular part of the symmetric matrix $A$.
val	is a one-dimensional array of size ne and type rpc_, that holds the values of the entries of the lower triangular part of the symmetric matrix $A$ in any of the supported storage schemes.

void psls_form_subset_preconditioner(
    void **data,
    ipc_ *status,
    ipc_ ne,
    const rpc_ val[],
    ipc_ n_sub,
    const ipc_ sub[]
)

Form and factorize a $P$ preconditioner of a symmetric submatrix of the matrix $A$.

Parameters:

data	holds private internal data
status	is a scalar variable of type ipc_, that gives the exit status from the package. Possible values are: 0 The factors were generated successfully. -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. -26 The requested solver is not available. -29 This option is not available with this solver.
ne	is a scalar variable of type ipc_, that holds the number of entries in the lower triangular part of the symmetric matrix $A$.
val	is a one-dimensional array of size ne and type rpc_, that holds the values of the entries of the lower triangular part of the symmetric matrix $A$ in any of the supported storage schemes.
n_sub	is a scalar variable of type ipc_, that holds the number of rows (and columns) of the required submatrix of $A$.
sub	is a one-dimensional array of size n_sub and type ipc_, that holds the indices of the rows of required submatrix.

void psls_update_preconditioner(
    void **data,
    ipc_ *status,
    ipc_ ne,
    const rpc_ val[],
    ipc_ n_del,
    const ipc_ del[]
)

Update the preconditioner $P$ when rows (amd columns) are removed.

Parameters:

data	holds private internal data
status	is a scalar variable of type ipc_, that gives the exit status from the package. Possible values are: 0 The factors were generated successfully. -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. -26 The requested solver is not available. -29 This option is not available with this solver.
ne	is a scalar variable of type ipc_, that holds the number of entries in the lower triangular part of the symmetric matrix $A$.
val	is a one-dimensional array of size ne and type rpc_, that holds the values of the entries of the lower triangular part of the symmetric matrix $A$ in any of the supported storage schemes.
n_del	is a scalar variable of type ipc_, that holds the number of rows (and columns) of (sub) matrix that are to be deleted.
del	is a one-dimensional array of size n_fix and type ipc_, that holds the indices of the rows that are to be deleted.

void psls_apply_preconditioner(void **data, ipc_ *status, ipc_ n, rpc_ sol[])

Solve the linear system $Px=b$.

Parameters:

data	holds private internal data
status	is a scalar variable of type ipc_, that gives the exit status from the package. Possible values are: 0 The required solution was obtained. -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.
n	is a scalar variable of type ipc_, that holds the number of entries in the vectors $b$ and $x$.
sol	is a one-dimensional array of size n and type double. On entry, it must hold the vector $b$. On a successful exit, its contains the solution $x$. Any component corresponding to rows/columns not in the initial subset recorded by psls_form_subset_preconditioner, or in those subsequently deleted by psls_update_preconditioner, will not be altered.

void psls_information(void **data, struct psls_inform_type* inform, ipc_ *status)

Provide output information

Parameters:

data

holds private internal data

inform

is a struct containing output information (see psls_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 psls_terminate(
    void **data,
    struct psls_control_type* control,
    struct psls_inform_type* inform
)

Deallocate all internal private storage

Parameters:

data	holds private internal data
control	is a struct containing control information (see psls_control_type)
inform	is a struct containing output information (see psls_inform_type)