Burst Time same as Required time Operating Systems - time

I have this table :
Process Time of arrival Required time Priority
-------- --------------- ------------- --------
P1 6 4 5
P2 2 9 2
P3 4 6 1
P4 10 4 30
SJF, SRTF, and Priority (Preemptive and non preemptive)
In the examples I see Burst time used , what is equivalent of that word should I use required time ?

Related

How to find max level in each path in a Oracle hierarchical SQL?

I would like to know the way to find the max level number in Oracle hierarchical SQL within the given path.
For example : If connect by clause starts with root 1 having below relation .
parent_id node_id votes
NULL 1 -
1 2 10
2 3 12
3 4 11
1 20 5
20 30 20
20 40 4
40 50 22
Here first 3 records belongs to one path with max levle 3.
Next 2 records belong to another path with max level 2.
Last two record belongs to another path with max level 3.
I need output with these max level within the given distinct path and minimum votes:
parent_id node_id LEVEL MAX_LEVL MIN_VOTE
1 2 1 3 10
2 3 2 3 10
3 4 3 3 10
1 20 1 2 5
20 30 2 2 5
1 20 1 3 4
20 40 2 3 4
40 50 3 3 4
1
|
--------------
| |
2 20
| |
3 --------------
| | |
4 30 40
|
50
Thanks,
Guru

Response time calculation in SJF NON PREEMPTIVE

process------ arrival------ burst_time
p1 0 3
p2 1 4
p3 2 5
I'm confused about the response time calculation. To calculate the response time is the arrival need to subtract or not? And what's the solution of this?

Convert between priority of two systems

I have two "systems" the with some records.
System A has record with priority from 1-4 (lets say minSystemAP = 4, maxSystemAP = 1).
System A Priority:
4 - Low, 3- Medium, 2 - High, 1 - Critical.
System B has record with priority from 1-10 (lets say minSystemBP = 10, maxSystemBP = 1).
System A Priority: 1-Minimum, 5- Medium, 10- High.
I'm trying to create record from System B in System A.
How can i "convert" between the priority of SystemA to SystemB?
Meaning, Record with priority 10 in System B will be record with priority ~ 4 in System A.
and record with priority 5 in System B will be record with priority ~ 2 in System A.
What is the best way to do that?
The mapping must assign multiple priorities in SystemB to one priority in SystemA.
E.g.:
A 1 1 2 2 2 3 3 3 4 4
B 1 2 3 4 5 6 7 8 9 10
This mapping-function would meet your requirements and can simply be implemented as integer-division:
int prioA = prioB / 3 + 1;

timetable scheduling using multidimensional priority table

I need a solution to schedule tasks on given dates for timetable scheduling. It is based on each user's vote. I have a table that contains number of votes for the task for the date:
Tasks: {"A","B","C","D","E"},
Dates: {"1 Jan","2 Jan","5 Jan","7 Jan","10 Jan"},
Total users: 16
A B C D E
=============================================
1-Jan | 6 3 1 4 2
2-Jan | 1 3 4 6 2
5-Jan | 2 3 3 1 7
7-Jan | 6 1 2 3 4
10-Jan | 1 6 5 3 1
For example, on 1-Jan, task A has 6 votes, task B has 3 votes, etc.
I need to schedule only one task for one date.
How to schedule tasks? Can anybody help?

KDB: pnl in FIFO manner

Consider the following table:
Id Verb Qty Price
`1 Buy 6 10.0
`2 Sell 5 11.0
`3 Buy 4 10.0
`4 Sell 3 11.0
`5 Sell 8 9.0
`6 Buy 1 8.0
etc...
What I would like is to associate a PNL with each transaction, computed on a FIFO (first-in-first-out basis). Thus, for Id=`1, I want the PNL to be -6*(10.0) +5*(11.0) + 1*(11.0) = +$6.00, for Id=`3, Pnl is -4*(10.0)+2*(11.0)+(2*9.0) = $0, etc.
In layman's terms, For the first buy-order of size 6, I want to offset this by the first 6 sells, and for the second buy-order of size 4, offset this with the subsequent 4 sells that have not been included in the pnl computation for the buy-6 order.
Any advice?
Take data from your example:
txn:([] t: til 6; side:`Buy`Sell`Buy`Sell`Sell`Buy; qty:6 5 4 3 8 1; px: 10.0 11.0 10.0 11.0 9.0 8.0)
Best to maintain buys and sells transactions/fills separately in your database:
buys: select from txn where side=`Buy
sells: select from txn where side=`Sell
Functions we'll need [1]:
/ first-in first-out allocation of bid/buy and ask/sell fills
/ returns connectivity matrix of (b)id fills in rows and (a)sk fills in columns
fifo: {deltas each deltas sums[x] &\: sums[y]};
/ connectivity list from connectivity matrix
lm: {raze(til count x),''where each x};
/ realized profit & loss
rpnl: {[b;s]
t: l,'f ./: l:lm (f:fifo[exec qty from b;exec qty from s])>0;
pnl: (select bt:t, bqty:qty, bpx:px from b#t[;0]),'(select st:t, sqty:qty, spx:px from s#t[;1]),'([] qty: t[;2]);
select tstamp: bt|st, rpnl:qty*spx-bpx from pnl
}
Run:
q)rpnl[buys;sells]
tstamp rpnl
-----------
1 5
3 1
3 2
4 -2
5 1
According to my timings, should be ~ 2x faster than the next best solution, since it's nicely vectorized.
Footnotes:
fifo function is a textbook example from Q for Mortals. In your case, it looks like this:
q)fifo[exec qty from buys;exec qty from sells]
5 1 0
0 2 2
0 0 1
lm function tells which buys and sell pairs were crossed (non-zero fills). More background here: [kdb+/q]: Convert adjacency matrix to adjacency list
q)lm fifo[exec qty from buys;exec qty from sells]>0
0 0
0 1
1 1
1 2
2 2
Cryptic first line of rpnl is then combination of the two concepts above:
q)t: l,'f ./: l:lm (f:fifo[exec qty from buys;exec qty from sells])>0;
0 0 5
0 1 1
1 1 2
1 2 2
2 2 1
A similar approach to JPC, but keeping things tabular:
q)tab:([] Id:`1`2`3`4`5`6;Verb:`Buy`Sell`Buy`Sell`Sell`Buy;Qty:6 5 4 3 8 1;Price:10.0 11.0 10.0 11.0 9.0 8.0)
q)tab
Id Verb Qty Price
-----------------
1 Buy 6 10
2 Sell 5 11
3 Buy 4 10
4 Sell 3 11
5 Sell 8 9
6 Buy 1 8
pnlinfo:{[x;y]
b:exec first'[(Qty;Price)] from x where Id=y;
r:exec (remQty;fifo[remQty;b 0];Price) from x where Verb=`Sell;
x:update remQty:r 1 from x where Verb=`Sell;
update pnl:neg[(*) . b]+sum[r[2]*r[0]-r[1]] from x where Id=y
};
fifo:{x-deltas y&sums x};
pnlinfo/[update remQty:Qty from tab where Verb=`Sell;exec Id from tab where Verb=`Buy]
Id Verb Qty Price remQty pnl
----------------------------
1 Buy 6 10 6
2 Sell 5 11 0
3 Buy 4 10 0
4 Sell 3 11 0
5 Sell 8 9 5
6 Buy 1 8 1
Assumes that Buys will be offset against previous sells as well as future sells.
You could also in theory use other distributions such as
lifo:{x-reverse deltas y&sums reverse x}
but I haven't tested that.
Here is a first attempt to get the ball rolling. Not efficient.
q)t:([]id:1+til 6;v:`b`s`b`s`s`b;qty:6 5 4 3 8 1; px:10 11 10 11 9 8)
//how much of each sale offsets a given purchase
q)alloc:last each (enlist d`s){(fx-c;c:deltas y&sums fx:first x)}\(d:exec qty by v from t)`b
//revenues, ie allocated sale * appropriate price
q)revs:alloc*\:exec px from t where v=`s
q)(sum each revs)-exec qty*px from t where v=`b
6 0 1
Slightly different approach without using over/scan(except in sums...).
Here we create a list of duplicated indices(one per unit Qty) of every Sell order and use cut to assign them to the appropriate Buy order, then we index into the Price of those Sells and find the difference with the Price of the appropriate Buy order.
This should scale with table size, but memory will blow up when Qty is large.
q)tab:([] Id:`1`2`3`4`5`6;Verb:`Buy`Sell`Buy`Sell`Sell`Buy;Qty:6 5 4 3 8 1;Price:10.0 11.0 10.0 11.0 9.0 8.0)
q)sideMap:`Buy`Sell!1 -1
q)update pnl:sum each neg Price - Price{sells:where neg 0&x; -1_(count[sells]&0,sums 0|x) _ sells}Qty*sideMap[Verb] from tab
Id Verb Qty Price pnl
---------------------
1 Buy 6 10 6
2 Sell 5 11 0
3 Buy 4 10 0
4 Sell 3 11 0
5 Sell 8 9 0
6 Buy 1 8 1

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