new ChainComplex -- make a new chain complex from scratch

new ChainComplex -- make a new chain complex from scratch

Synopsis:

Operator: NewMethod

Input:

an instance of class ChainComplex.

Output:

an instance of class ChainComplex.

C = new ChainComplex -- make a new chain complex.

The new chain complex is initialized with a differential of degree -1 accessible as C.dd and of type ChainComplexMap. You can take the new chain complex and fill in the ring, the modules, and the differentials.

i1 : C = new ChainComplex;

i2 : C.ring = ZZ;

i3 : C#2 = ZZ^1;

i4 : C#3 = ZZ^2;

i5 : C.dd#3 = matrix {{3,-11}};



              1        2

o5 : Matrix ZZ  <--- ZZ

i6 : C



       1       2

o6 = ZZ  <-- ZZ

              

     2       3



o6 : ChainComplex

i7 : C.dd



           1                  2

o7 = 2 : ZZ  <------------- ZZ  : 3

                | 3 -11 |



o7 : ChainComplexMap

Code:

     -- ../../../Macaulay2/m2/chaincomplexes.m2:10-15
     new ChainComplex := ChainComplex => (cl) -> (
          C := newClass(ChainComplex,new MutableHashTable); -- sigh
          b := C.dd = new ChainComplexMap;
          b.degree = -1;
          b.source = b.target = C;
          C)