SQL & PL/SQL :: Compute Based On Columns As Variables

My issue is with a calculation using columns as variables. below is the code to create and attached is the code (INSERT_data.txt) to fill-in the required tables....

what's required here?

I need to update (through update or simply create new table statement)

BPF(i), BPC(i), BPY(i) of table root_tbl (A) based on InF_IDX, InC_IDX & InY_IDX and OutF_IDX, OutC_IDX & OutY_IDX using BPF(i), BPC(i), BPY(i) from table pvt_vectors_tbl(B).

Join Clause: A.P_NODE=B..P_NODE and
A.C_NODE=B.C_NODE and
A.P_NODE_Date=B.P_NODE_Date and
A.C_NODE_Date=B.C_NODE_Date

the formula are:

BPF(i):
if A.InF_IDX<=A.OutF_IDX then
FOR i=1 to A.OutF_IDX+1
if i<InF_IDX then A.BPF(i)= A.BPF(i)+ B.BPF(OutF_IDX + i - InF_IDX); else A.BPF(i)=0;
i=i+1;
else
FOR i=1 to A.InF_IDX+1
if i<OutF_IDX then A.BPF(i)= A.BPF(i)+ B.BPF(InF_IDX + i - OutF_IDX); else A.BPF(i)=0;
i=i+1;
idem for BPc and BPY.

in real word:

* root_tbl table has ~2 million records, 50 BPF(i) columns, 50 BPC(i) columns and ~475 BPY(i) columns
* pvt_vectors_tbl has ~50.000 records

/*create and fill-in pvt_vectors_tbl table*/

CREATE TABLE root_tbl
(
P_NODE VARCHAR2(3),
C_NODE VARCHAR2(3),
P_NODE_Date date,
C_NODE_Date date,
InF_IDX number,
InC_IDX number,
InY_IDX number,
[code].........