# Difference between revisions of "ApCoCoA-1:Slinalg.SEF"

## Slinalg.SEF

Calculates the Echelon form of a sparse matrix over F2.

### Syntax

```Slinalg.SEF(NRow : INT ,NCol : INT, Mat : LIST)
```

### Description

Please note: The function(s) explained on this page is/are using the ApCoCoAServer. You will have to start the ApCoCoAServer in order to use it/them.

• @param NRow: Number of rows of the matrix.

• @param NCol: Number of Columns of the matrix.

• @param Mat: List of lists containing positions of non zero elements.

• @return A list of lists containing the Echelon form of the matrix.

#### Example

```Use ZZ/(2)[x];
M := [[1, 2, 6,	7], [1, 2, 4, 5,6], [2,	3], [2,	3, 10, 11], [2,	4, 6, 7, 9, 10], [2, 10, 11, 13], [5, 6, 8], [ 6, 8, 9,	10,12],
[6, 10,	12], [ 10, 13]];
NRow:=10;
NCol:=13;

Slinalg.SEF(NRow, NCol, M);
Mat([
[1, 2, 3],
[4, 5, 6],
[7, 8, 9],
[11, 12, 13]
])
-------------------------------
Mat([
[1 % 239, 2 % 239, 3 % 239],
[0 % 239, 1 % 239, 2 % 239],
[0 % 239, 0 % 239, 0 % 239],
[0 % 239, 0 % 239, 0 % 239]
])
-------------------------------

```