overview of functions provided#

// typedefs

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

// structs

struct uls_control_type;
struct uls_inform_type;

// global functions

void uls_initialize(
    const char solver[],
    void **data,
    struct uls_control_type* control,
    ipc_ *status
);

void uls_read_specfile(struct uls_control_type* control, const char specfile[]);

void uls_factorize_matrix(
    struct uls_control_type* control,
    void **data,
    ipc_ *status,
    ipc_ m,
    ipc_ n,
    const char type[],
    ipc_ ne,
    const rpc_ val[],
    const ipc_ row[],
    const ipc_ col[],
    const ipc_ ptr[]
);

void uls_reset_control(
    struct uls_control_type* control,
    void **data,
    ipc_ *status
);

void uls_solve_system(
    void **data,
    ipc_ *status,
    ipc_ m,
    ipc_ n,
    rpc_ sol[],
    bool trans
);

void uls_information(void **data, struct uls_inform_type* inform, ipc_ *status);

void uls_terminate(
    void **data,
    struct uls_control_type* control,
    struct uls_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 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 uls_initialize below will instead be

void uls_initialize_s_64(const char solver[],  void **data,
                         struct uls_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 uls_initialize(const char solver[], void **data,
                    struct uls_control_type* control,
                    ipc_ *status)

Set default control values and initialize private data

Select solver, set default control values and initialize private data

Parameters:

solver	is a one-dimensional array of type char that specifies the solver package that should be used to factorize the matrix $A$. It should be one of ‘gls’, ‘ma28’, ‘ma48 or ‘getr’; lower or upper case variants are allowed. Only ‘getr’ is available by default, but others are easily installed (see README.external).
data	holds private internal data
control	is a struct containing control information (see uls_control_type)
status	is a scalar variable of type ipc_, that gives the exit status from the package. Possible values are: 0 The initialization was successful. -26 The requested solver is not available**

void uls_read_specfile(struct uls_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/uls/ULS.template. See also Table 2.1 in the Fortran documentation provided in $GALAHAD/doc/uls.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 uls_control_type)
specfile	is a character string containing the name of the specification file

void uls_factorize_matrix(
    struct uls_control_type* control,
    void **data,
    ipc_ *status,
    ipc_ m,
    ipc_ n,
    const char type[],
    ipc_ ne,
    const rpc_ val[],
    const ipc_ row[],
    const ipc_ col[],
    const ipc_ ptr[]
)

Import matrix data into internal storage prior to solution, analyse the sparsity patern, and subsequently factorize the matrix

Parameters:

control	is a struct whose members provide control paramters for the remaining prcedures (see uls_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: 0 The import, analysis and factorization were conducted 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. -3 The restrictions n > 0 and m> 0 or requirement that the matrix type must contain the relevant string ‘dense’, ‘coordinate’ or ‘sparse_by_rows has been violated. -26 The requested solver is not available. -29 This option is not available with this solver. -32 More than control.max integer factor size words of internal integer storage are required for in-core factorization. -50 A solver-specific error occurred; check the solver-specific information component of inform along with the solver’s documentation for more details.
m	is a scalar variable of type ipc_, that holds the number of rows in the unsymmetric matrix $A$.
n	is a scalar variable of type ipc_, that holds the number of columns in the unsymmetric matrix $A$.
type	is a one-dimensional array of type char that specifies the unsymmetric 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 $A$ in the sparse co-ordinate storage scheme. It need not be set for any of the other schemes.
val	is a one-dimensional array of size ne and type rpc_, that holds the values of the entries of the matrix $A$ in any of the supported storage schemes.
row	is a one-dimensional array of size ne and type ipc_, that holds the row indices of the matrix $A$ 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 matrix $A$ in either the sparse co-ordinate, or the sparse row-wise storage scheme. It need not be set when the dense storage schemes is used, and in this case can be NULL.
ptr	is a one-dimensional array of size m+1 and type ipc_, that holds the starting position of each row of the matrix $A$, 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 uls_reset_control(
    struct uls_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 uls_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:

0
The import was successful.

void uls_solve_system(
    void **data,
    ipc_ *status,
    ipc_ m,
    ipc_ n,
    rpc_ sol[],
    bool trans
)

Solve the linear system $Ax=b$ or $A^Tx=b$.

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. -34 The package PARDISO failed; check the solver-specific information components inform.pardiso iparm and inform.pardiso_dparm along with PARDISO’s documentation for more details. -35 The package WSMP failed; check the solver-specific information components inform.wsmp_iparm and inform.wsmp dparm along with WSMP’s documentation for more details.
m	is a scalar variable of type ipc_, that holds the number of rows in the unsymmetric matrix $A$.
n	is a scalar variable of type ipc_, that holds the number of columns in the unsymmetric matrix $A$.
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 $x$.
trans	is a scalar variable of type bool, that specifies whether to solve the equation $A^Tx=b$ (trans=true) or $Ax=b$ (trans=false).

void uls_information(void **data, struct uls_inform_type* inform, ipc_ *status)

Provides output information

Parameters:

data

holds private internal data

inform

is a struct containing output information (see uls_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 uls_terminate(
    void **data,
    struct uls_control_type* control,
    struct uls_inform_type* inform
)

Deallocate all internal private storage

Parameters:

data	holds private internal data
control	is a struct containing control information (see uls_control_type)
inform	is a struct containing output information (see uls_inform_type)