Scilab Home page | Wiki | Bug tracker | Forge | Mailing list archives | ATOMS | File exchange
Change language to: Français - Português - 日本語 - Русский
Scilab Help >> Polynomials > coffg

# coffg

Co-factors of a matrix of polynomials or rationals

### Syntax

`[tC, d] = coffg(M)`

### Arguments

M

square matrix of numbers or polynomials or rationals, with real or complex coefficients.

tC

square matrix of the type of `M`: Transposed co-matrix of `M`, such that `tC/d` is equal to `inv(M)`.

d

scalar: determinant `det(M)`, with the `M`'s data type and encoding.

### Description

`coffg(M)` computes co-factors of `M`, and returns the transposed co-matrix `tC`.

When `M` has a single component, `tC` is `1` and `d==M`

 For large matrices, calculations may be slow.

### Examples

```// With polynomials
a = [ %s, %s^2+1; %s  %s^2-1];
[a1, d] = coffg(a)
(a1/d) - inv(a)

// With rationals
a = [%s 0 ; 0 1/%s]
[a1, d] = coffg(a)
(a1/d) - inv(a)```

• inv — matrix inverse
• invr — inversion of (rational) matrix
• glever — inverse of matrix pencil
• determ — determinant of polynomial matrix
• detr — polynomial determinant