Krzysiaczek99
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3.3 Effect of Network Parameters
The parameters that must be chosen for the neural networks
are the number of layers in the network and the number
of neurons in each layer. Note that the number of neurons
in the input layer is the choice for the number of price
return inputs given to the network (minus one for the recurrent
input.) Examining tables 1 and 2, one of the most striking
results of this study is that a neural network with a single
layer outperforms a neural network with two layers. This
may seem like a surprise because 2 layer networks are generally
a more powerful learning model; a single layer neural
network can only make decisions that are linearly separable
in the space of the inputs [5]. However, the high level
of noise in financial data may make the learning ability of
the two layer network a liability if it memorizes noise in the
input data. On the other hand, this result seems to imply
that reasonably good trading decisions for FX markets are
in some sense linearly separable in the space of the recent
price returns and therefore not as complex as we may believe.
Figure 2 shows the effect of the number of price return
inputs on the performance of a single layer neural network
trader. The results shown for three currency markets display
the difficulty of choosing fixed parameters for neural
network currency traders.
While the trader performs best in the Australian Dollar -
US Dollar (AUD-USD) market with fewer inputs, its performance
in the - Dollar - Dutch Guilder (USD-NLG) market
is best with a larger number of inputs. In the GBP-USD
market performance is best at fewer inputs, but the worst
performance is for traders with an intermediate number of
inputs. This seems to defy common sense, yet the the result
is a genuine quirk of the market. The final number of
price inputs that was chosen to optimize the average performance
in the tuning markets was 4. This results is also
rather surprising because it means that the neural network
traders only need the price returns from the most recent two
hours in order to make effective trading decisions.
Comparing the profit with the Sharpe Ratio for the currency
markets in figure 2 shows that there does not appear
to be a tradeoff between profit and stability of returns when
choosing the optimal values for the fixed parameters of the
model. The number of inputs that has the highest profit has
the highest Sharpe Ratio as well. This was true for nearly
all of the fixed parameters and currency markets.
Walczak (2001) has examined the issue of length of the training set or
in-sample data size for producing accurate forecasts in financial markets.
He found that for most exchange-rate predictions (on a daily basis), a
maximum of two years produces the “best neural network forecasting model
performance” [Walczak (2001), p. 205]. Walczak calls the use of data closer
in time to the data that are to be forecast the times-series recency effect.
Use of more recent data can improve forecast accuracy by 5% or more while
reducing the training and development time for neural network models
[Walczak (2001), p. 205].
Walczak measures the accuracy of his forecasts not by the root mean
squared error criterion but by percentage of correct out-of-sample direction
of change forecasts, or directional accuracy, taken up by Pesaran and
Timmerman (1992). As in most studies, he found that single-hidden-layer
neural networks consistently outperformed two-layer neural networks, and
that they are capable of reaching the 60% accuracy threshold [Walczak
(2001), p. 211].
I do not think so, refer to page 2 I split the row data for training (7004 bars) and applying/out of sample (1126 bars) as your original prediction. On the page 4 for the training bars and page 5 to implement the trained net on out of sample data.
I think should no more leak..hence we should test it on real time walk forward data
Arry
Man, you guys move fast. I turn my head for a minute and I lose trackLook at this. Contradicts with idea of MM analysis
Man, you guys move fast. I turn my head for a minute and I lose track
My comment on the paper from CalTech:
Multi-markets may be BS, but I'm not sure this paper can be used as evidence. I have to read it again, but their results seem consistent with what Mendelsohn claims. Different markets are better predicted with different inputs. e.g. CHF and Gold might help to predict the price of the EUR, but you might need USD and Oil to predict the price of the GBP. These guys seem to try to find a single network model that works for all FX pairs. I think that means the same inputs, and same learning parameters. I guess that if successful, that might increase your confidence, but given that currencies have varying characteristics, like volatility and to some extent spectrum, and that some currencies are correlated with others, I would not expect a single model to work as well as a set of models each tuned to the pair it will work with.
This doesn't mean that I believe in multi market models, but I think it may be too early to throw them out. Not much else seems to work well.
Now to go back and see what you're doing.
fralo/MadCow
Fralo,
Here is the NS2 output file, it includes all train and test patterns, including actual, prediction and their differences.
Kryzs, you can verify with the output data to calculate your MSE or RMS. I just shown the actual result..without any adjustment..
Arry
Can you convert the zipped xlsx file to xls? Excel 2003 can't read it, and I don't want to give Bill Gates any more cash.Here are two nets from MBP trained with CUDA for 150 000 epochs with configuration
15-30-10-1 and 15-30-1. Objective was to check the impact of additional layer of neurons.
There is also excel sheet which calculates absolute error, stdev and correct sign for those nets. Clearly adding extra layer of neurons introduces stronger error level.
I believe we can try to extend functions of this sheet to make deeper analysis of nets.
Pass is the same what Arry is using in his PDFs.
Im training now configuration 15-30-30-1 to confirm impact of additional layers.
Perhaps arry you can use this sheet to calculate correct sign of NS2 and Predictor nets
because this what is shown in your report is impossible. Just have a look how i did it and double check it of course.
Krzysztof