callable functions

    function sha_initialize(T, 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 sha_control_type)
status	is a scalar variable of type Int32 that gives the exit status from the package. Possible values are (currently): 0 The initialization was successful.

    function sha_read_specfile(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/sha/SHA.template. See also Table 2.1 in the Fortran documentation provided in $GALAHAD/doc/sha.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 sha_control_type)
specfile	is a one-dimensional array of type Vararg{Cchar} that must give the name of the specification file

    function sha_analyse_matrix(T, control, data, status, n, ne, row, col, m)

Analsyse the sparsity structure of \(H\) to generate information that will be used when estimating its values.

Parameters:

control	is a structure whose members provide control paramters for the remaining prcedures (see sha_control_type)
data	holds private internal data
status	is a scalar variable of type Int32 that gives the exit status from the package. Possible values are: 0 The import and analysis were conducted successfully. 1 Insufficient data pairs \((s_i,y_i)\) have been provided, as m is too small. The returned \(B\) is likely not fully accurate. -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 A restriction n > 0, ne \(\geq\) 0 or 0 \(\leq\) row[i] \(\leq\) col[i] \(\leq\) n has been violated.
n	is a scalar variable of type Int32, that holds the number of variables
ne	is a scalar variable of type Int32, that holds the number of entries in the upper triangular part of \(H\).
row	is a one-dimensional array of size ne and type Int32, that holds the row indices of the upper triangular part of \(H\).
col	is a one-dimensional array of size ne and type Int32, that holds the column indices of the upper triangular part of \(H\).
m	is a scalar variable of type Int32, that gives the minimum number of \((s^{(k)},y^{(k)})\) pairs that will be needed to recover a good Hessian approximation.

    function sha_recover_matrix(T, data, status, ne, m, ls1, ls2, strans,
                                ly1, ly2, ytrans, val, order)

Estimate the nonzero entries of the Hessian \(H\) by component-wise secant approximation.

Parameters:

data	holds private internal data
status	is a scalar variable of type Int32 that gives the exit status from the package. Possible values are: 0 The recovery was successful. -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. -31 sha.recover_matrix has been called before sha.analyse_matrix.
ne	is a scalar variable of type Int32 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 T that holds the values of the entries of the lower triangular part of the symmetric matrix \(A\) in any of the supported storage schemes.
ne	is a scalar variable of type Int32, that holds the number of entries in the upper triangular part of \(H\).
m_available	is a scalar variable of type Int32, that holds the number of differences provided. Ideally this will be as large as m as reported by sha_analyse_matrix, but better still there should be a further control.extra_differences to allow for unlikely singularities.
ls1	is a scalar variable of type Int32, that holds the leading (first) dimension of the array strans.
ls2	is a scalar variable of type Int32, that holds the trailing (second) dimension of the array strans.
strans	is a two-dimensional array of size [ls1][ls2] and type T, that holds the values of the vectors \(\{s^{(k) T}\}\). Component [\(k\)][\(i\)] should hold \(s_i^{(k)}\).
ly1	is a scalar variable of type Int32, that holds the leading (first) dimension of the array ytrans.
ly2	is a scalar variable of type Int32, that holds the trailing (second) dimension of the array ytrans.
ytrans	is a two-dimensional array of size [ly1][ly2] and type T, that holds the values of the vectors \(\{y^{(k) T}\}\). Component [\(k\)][\(i\)] should hold \(y_i^{(k)}\).
val	is a one-dimensional array of size ne and type T, that holds the values of the entries of the upper triangular part of the symmetric matrix \(H\) in the sparse coordinate scheme.
order	is a one-dimensional array of size m and type Int32, that holds the preferred order of access for the pairs \(\{(s^{(k)},y^{(k)})\}\). The \(k\)-th component of order specifies the row number of strans and ytrans that will be used as the \(k\)-th most favoured. order need not be set if the natural order, \(k, k = 1,...,\) m, is desired, and this case order should be C_NULL.

    function sha_information(T, data, inform, status)

Provides output information

Parameters:

data	holds private internal data
inform	is a structure containing output information (see sha_inform_type)
status	is a scalar variable of type Int32 that gives the exit status from the package. Possible values are (currently): 0 The values were recorded successfully

    function sha_terminate(T, data, control, inform)

Deallocate all internal private storage

Parameters:

data	holds private internal data
control	is a structure containing control information (see sha_control_type)
inform	is a structure containing output information (see sha_inform_type)