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Resources for matrix calculus for optimization 27 Aug 2013 | 08:29 pm
I'm a grad student trying to absorb from the book Pattern Recognition and Machine Learning. However, I found that I really need a good grasp of matrix calculus before I can deduct the formulas myself ...
Confusion related to elastic net 27 Aug 2013 | 07:05 pm
I was reading this article related to elastic net. They say that they use elastic net because if we just use Lasso it tends to select only one predictor among the predictors that are highly correlated...
Gibbs sampling to produce posterior pdf 27 Aug 2013 | 04:55 pm
Suppose we have the following classical normal linear regression model: $$y_i = \beta_1 x_{1i} + \beta_2x_{2i} + \beta_3x_{3i} + e_i$$ where $e_{i} \sim iid.N(0, \sigma^2)$ for all $i = 1, 2, \cdots...
Smooth a circular/periodic time series 27 Aug 2013 | 01:09 pm
I have data for motor vehicle crashes by hour of the day. As you would expect, they are high in the middle of the day and peak at rush-hour. ggplot2's default geom_density smooths it out nicely A sub...
Title of my thesis that should includes Generative bayesian and optimization techniques 27 Aug 2013 | 11:34 am
I am struggling to get a single word that would imply both Generative Bayesian and Optimization technique. I am looking for my thesis topic that goes currently like "Generative Bayesian and optimizati...
Plot log-normal distribution in R 27 Aug 2013 | 08:35 am
I need to plot lognormal distribution with mean 1 and variance 0.6 in R. I tried to do this using rlnorm function in R as log(0.6) is negative that might be the reason my code is not working but the ...
Multi target regression using neural networks in matlab 27 Aug 2013 | 08:28 am
I am new to neural networks tool in matlab. I have a certain data with 100 features and 5 targets. I want to learn a multi target non linear function using neural networks in matlab. So given features...
Using mae for performance function in matlab nntool 27 Aug 2013 | 08:01 am
I am trying to use matlab's neural network tool to fit a function to my data. I was thinking of using mae as my performance measure. However, I couldn't find that option. I could only get mse and sse....
Hessian of logistic function 27 Aug 2013 | 07:07 am
I have difficulty to derive the Hessian of the objective function, $l(\theta)$, in logistic regression where $l(\theta)$ is: $$ l(\theta)=\sum_{i=1}^{m} \left[y_{i} \log(h_\theta(x_{i})) + (1- y_{i}) ...
Treatment of triple seasonal data 27 Aug 2013 | 06:10 am
I have a data set of electricity spot prices, which contains three kinds of seasonality: one within 24 hours, one within a week and one within a year. I want to use an R package ('tsDyn') which can't...
