callable functions#

    function nodend_initialize(INT, data, control, status)

Set default control values and initialize private data

Parameters:

data

holds private internal data

control

is a structure containing control information (see nodend_control_type)

status

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

  • 0

    The initialization was successful.

 
    function nodend_read_specfile(INT, control, 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 structure containing control information (see nodend_control_type)

specfile

is a one-dimensional array of type Vararg{Cchar} that must give the name of the specification file

 
    function nodend_order(INT, control, data, status, n, perm,
                          A_type, ne, A_row, A_col, A_ptr)

Order problem data into internal storage prior to solution.

Parameters:

control

is a structure whose members provide control parameters for the remaining procedures (see nodend_control_type)

data

holds private internal data

status

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

  • 1

    The order 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

    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 INT that holds the number of variables.

perm

is a one-dimensional array of size n and type INT, 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 Vararg{Cchar} that specifies the symmetric storage scheme used \(A\). 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 INT 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 the other scheme.

A_row

is a one-dimensional array of size ne and type INT 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 C_NULL

A_col

is a one-dimensional array of size ne and type INT 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 INT 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 C_NULL

 
    function nodend_information(INT, data, inform, status)

Provides output information

Parameters:

data

holds private internal data

inform

is a structure containing output information (see nodend_inform_type)

status

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

  • 0

    The values were recorded successfully