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### 4 Tool functions

#### 4.1 Read and write matrix

##### 4.1-1 4ti2Interface_Read_Matrix_From_File

`‣ 4ti2Interface_Read_Matrix_From_File` ( `arg` ) | ( function ) |

Returns: a list of vectors

The argument must be a string, representing a filename of a matrix to read. Numbers must be seperated by whitespace, and the first two numbers must be the number of rows and columns. The function then returns the matrix as list of lists.

##### 4.1-2 4ti2Interface_Write_Matrix_To_File

`‣ 4ti2Interface_Write_Matrix_To_File` ( `arg` ) | ( function ) |

Returns: nothing

First argument must be a matrix, i.e. a list of list of integers. Second argument has to be a filename. The method stores the matrix in this file, seperated by whitespace, line by line. The content of the file, if there is any, will be deleted.

##### 4.1-3 4ti2Interface_Cut_Vector

`‣ 4ti2Interface_Cut_Vector` ( `vec`, `d` ) | ( function ) |

Returns: a matrix

Takes the vector `vec` and produces a matrix with `d` columns out of the entries of the vector.