This function can be used in external code with OpenMaple or define_external.

RTableDataBlock returns a pointer to the data contained in the given rtable, rt.  The returned pointer must be cast into the correct hardware datatype to access elements. The data type can be obtained from the data_type field of the RTableSettings structure returned by RTableGetSettings.

Before modifying data in the data block, ensure the rtable rt is not read-only.  The read-only flag value can be obtained from the read_only field of the RTableSettings structure returned by RTableGetSettings.

Do not directly modify the data block of an rtable with an indexing function.  The data stored in position [1,1] of an rtable with a special indexing function may not correspond to the [1,1] element accessed from the rtable.

An error is raised if an attempt is made to get the data block from a Maple-sparse rtable.

$\mathrm{with}\left(\mathrm{ExternalCalling}\right)\:$

$\mathrm{dll}≔\mathrm{ExternalLibraryName}\left(''HelpExamples''\right)\:$

$\mathrm{sum\_elems}≔\mathrm{DefineExternal}\left(''MySumElems''\,\mathrm{dll}\right)\:$

$M≔\mathrm{Matrix}\left(3\,\left(i\,j\right)\mapsto 3\cdot i-3+j\,\mathrm{datatype}=\mathrm{float}\left[8\right]\right)$

$M≔\left[\begin{array}{ccc}1.& 2.& 3.\\ 4.& 5.& 6.\\ 7.& 8.& 9.\end{array}\right]$

$\mathrm{sum\_elems}\left(M\right)$

$45.$