Depending on the requirements of a run, NEC-2 may use the following files.
The scratch files are used only when the matrix will not fit into core stroage. Fro a case that does not use the NGF (but may write a NGF file), there are five options for matrix storage. IF
then the case, indicated by the value of ICASE in the code, are
File storage is used in cases 3,4 and 5. Only the four files (11,12,13 and 14) are used when the NGF is not in use. The size of each file is approximately @NNx words. If the computer system requires that the user specify the file size, a safety margin should be included in the request. A more accurate estimate of the file size is
and [ ] indicates truncation. Nc, which is the number of matrix columns in I/O block, must be at least 1.
When the NGF is used, all six scratch files may be
required. For the NGF the matrix is partitioned into
four sections as
_ _ |A B| |C D| - -
A is the matrix for the NGF structure and is factored before the NGFfile is written. The stroage case for A is indicated in the NGFlable by the value of ICASE (see exampel 10 in section IV). When the NGF is used, matrix A is read from file 20 and, if ICASE is 3,4, or 5, is stored on file 13. The size of file 13 when the NGF is used is approximately:
ICASE Length of file 13 3 4N
2 4 2NNx 5 4NNx There are four options for
storage of the matrices B, C, and D. these are associated with the integer
ICASX as follows:
The sizees of matrices B, C, and D depend on the number of new unknowns Nn where
The sizes of matrices B and C are 2NNn and the size of D is 2Nn2 words. The file lengths are approximately 2Nn2 words for files 11 and 12 and 2NNn for files 14, 15 and 16. when ICASX is 1 these files are not used, and when ICASX is 2 file 16 is not used.
The length of the NGF file (20) is approximately 4N(Nx+3). The length of the Summerfeld/Norton data file (21) is about 2200 words.