# Difference between revisions of "ApCoCoA-1:NC.CoCoALToC"

## NC.CoCoALToC

Convert a polynomial in a non-commutative polynomial ring from the CoCoAL format to the C format.

### Syntax

```NC.CoCoALToC(F:LIST):INT
```

### Description

Please set non-commutative polynomial ring (via the command Use) before calling this function. For more information, please check the relevant commands and functions.

• @param F: a non-commutative polynomial in the CoCoAL format. Each polynomial is represented as a LIST of LISTs, and each element in every inner LIST involves only one indeterminate or none (a constant). For example, the polynomial f=2x[2]y[1]x[2]^2-9y[2]x[1]^2x[2]^3+5 is represented as F:=[[2x[1],y[1],x[2]^2], [-9y[2],x[1]^2,x[2]^3], [5]]. The zero polynomial 0 is represented as the empty LIST [].

• @return: a LIST, which is the C format of the polynomial F.

#### Example

```USE QQ[x[1..2],y[1..2]];
F:= [[2x[1],y[1],x[2]^2], [-9y[2],x[1]^2,x[2]^3], [5]]; --2x[1]y[1]x[2]^2-9y[2]x[1]^2x[2]^3+5
NC.CoCoALToC(F);

[[2, [1, 3, 2, 2]], [-9, [4, 1, 1, 2, 2, 2]], [5, [ ]]]
-------------------------------
```