length ChainComplex -- length of a chain complex or graded module

length ChainComplex -- length of a chain complex or graded module

Synopsis:

Function: length -- length

Input:

an instance of class ChainComplex.

Output:

an instance of class ZZ.

length C -- the length of a chain complex.

The length of a chain complex is defined to be the difference between the smallest and largest indices of spots occupied by modules, even if those modules happen to be zero.

Code:

     -- ../../../Macaulay2/m2/chaincomplexes.m2:44-47
     length ChainComplex := (C) -> (
          s := select(spots complete C, i -> C_i != 0);
          if #s === 0 then 0 else max s - min s
          )