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by Bon
July 28th, 2009, 9:11 am
Forum: Numerical Methods Forum
Topic: Local vol in finite difference
Replies: 7
Views: 39896

Local vol in finite difference

Yes. It turns out that there's a bug in the boundary condition, and more importantly, my min/max nodes are not far apart enough when local vol on both ends are very high! (about 400% at 3sd from current spot)
by Bon
July 14th, 2009, 12:41 am
Forum: Numerical Methods Forum
Topic: Local vol in finite difference
Replies: 7
Views: 39896

Local vol in finite difference

Thanks!
by Bon
July 9th, 2009, 2:46 am
Forum: Numerical Methods Forum
Topic: Local vol in finite difference
Replies: 7
Views: 39896

Local vol in finite difference

<t>. which FDM are you using? implicit scheme, using the Black-Scholes PDE with underlying variable = log(S). relative sizes of vol versus drift? implied vol goes from 50% to 85% across strikes, which makes local vol roughly 50% to 170%. Interest rate and cts div are zero, so drift of log(S) is -sig...
by Bon
July 8th, 2009, 7:12 am
Forum: Numerical Methods Forum
Topic: Local vol in finite difference
Replies: 7
Views: 39896

Local vol in finite difference

<t>Hi guys,I wonder if there is any experience in troubles using finite difference (just implicit scheme) when local vol is used. I'm only solving for European style options using log(S) as underlying variable. When I passed in a flat surface, the price and every thing looks fine. But when I pass in...
by Bon
June 23rd, 2009, 7:57 am
Forum: Technical Forum
Topic: Simulating LV process
Replies: 21
Views: 43345

Simulating LV process

<t>But won't it be the same as simulating a forward start option using small dt steps? My goal is not to get a forward starting price. It is to find an algorithm that can avoid simulating a long dated option without resorting to tiny time steps, yet the distribution remains the same. I don't see how...
by Bon
June 18th, 2009, 1:41 am
Forum: Technical Forum
Topic: Simulating LV process
Replies: 21
Views: 43345

Simulating LV process

<t>Hi Alan,Actually, I am assuming the local vol process holds until the maturity of my option.dS / S = (r-q)dt * sigma(S, t) dWUnder this assumption, I think we can indeed back out the forward starting option from the generated local vol surface, in a sort of "Sticky Surface" way.If we simulate the...
by Bon
June 17th, 2009, 6:15 am
Forum: Technical Forum
Topic: Simulating LV process
Replies: 21
Views: 43345

Simulating LV process

<t>My idea is that we can convert the local vol surface to implied vol surface at any time and any stock price level.For instance, say we're simulating the process at T1, T2, T3, ... , Tn, given S0 and vanilla prices at all strikes and maturities (basically, the local vol function). In order to simu...
by Bon
June 17th, 2009, 5:38 am
Forum: Technical Forum
Topic: Simulating LV process
Replies: 21
Views: 43345

Simulating LV process

Does all these discussion imply that although we can find the law of S from T_0 to T_1, we still can't find the law of S from T_1 to T_2, given S_1? My information, of course, is all vanilla prices over all strikes and maturities.
by Bon
June 10th, 2009, 6:34 am
Forum: Brainteaser Forum
Topic: Finding arbitrage opportunities in bonds?
Replies: 4
Views: 48612

Finding arbitrage opportunities in bonds?

<t>first one:long 0.1 B1, long 1.1 B2, short 1 B3at day zero, cost is0.1 * 95 + 1.1 * 90 - 100 = 8.5cashflow at 1yr:0.1 * 100 - 10 = 0cashflow at 2yr:1.1 * 100 - 110 = 0So riskfree profit = 8.5 at day zero.The idea of the rest is the same. Two of the bonds can give the zero bond price. The third can...
by Bon
June 4th, 2009, 8:03 am
Forum: Technical Forum
Topic: Simulating LV process
Replies: 21
Views: 43345

Simulating LV process

<t>Hi guys,I wonder if anyone can enlighten me on simulating a local volatility process without resorting to small time step sizes.In a flat surface, we can simulate from time t1 to t2 directly by sqrt(int(sigma^2, t=t1... t2)) * Z as the random term because it has the same distribution as int(sigma...
by Bon
March 18th, 2009, 12:59 am
Forum: Numerical Methods Forum
Topic: Moments computation
Replies: 1
Views: 42014

Moments computation

<t>I believe you meantdA(t)=mu A(t)dt+sigma A(t) dW_tSince A(t)=A(0) exp[(mu -0.5 sigma^2)t + sigma W_t].E[A(t)] = A(0) exp[(mu -0.5 sigma^2)t] E[exp(sigma W_t)].Now sigma W_t ~ N(0, sigma^2 t), soE[A(t)] = A(0) exp[(mu -0.5 sigma^2)t] exp[0.5 sigma^2 t].= A(0) exp[mu*t]Similarly,E[A(t)^2] = A(0)^2 ...
by Bon
March 17th, 2009, 10:03 am
Forum: Numerical Methods Forum
Topic: Basket volatility surface
Replies: 1
Views: 44500

Basket volatility surface

<t>This topic has been raised multiply times already, but I still haven't found a satisfying solution! The problem is:Consider a basket to be a weighted average of underlying assets with fixed weights. Given the implied volatility surfaces of the assets and a fixed correlation matrix, how can we app...
by Bon
November 27th, 2008, 12:44 am
Forum: Numerical Methods Forum
Topic: The Alternating Direction Explicit (ADE) Method Thread
Replies: 146
Views: 182624

The Alternating Direction Explicit (ADE) Method Thread

Hi Daniel,You've mentioned that you have the code for your MADE (very fast FDM) in your book? Are you referring to "FMD in FE, a PDE approach"?I have the book but no CD with me, but I don't seem to find such info even in the text.
by Bon
January 10th, 2008, 7:13 am
Forum: Brainteaser Forum
Topic: A question from Goldman Sachs interview
Replies: 11
Views: 68987

A question from Goldman Sachs interview

<t>Suppose the stock S follows a geometric Brownian motion. Assume zero interest rate and dividend. Consider the two options:Option A: Pays $1 at the end of 2nd year if stock > 100, nothing otherwiseOption B: Pays $1 at any time from now until the end of 2nd year when stock > 100. Once this is paid ...
by Bon
August 7th, 2007, 5:07 am
Forum: Numerical Methods Forum
Topic: parallel programming for Matrix class
Replies: 3
Views: 68960

parallel programming for Matrix class

If I'm dealing with very large matrices, what kind of common operations that would reasonably implemented with parallel programming?In that regard, how does the performance of QR factorization compare to that of SVD in computing the inverse of a matrix?