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project euler – Problem 32

November 8, 2011
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We shall say that an n-digit number is pandigital if it makes use of all the digits 1 to n exactly once; for example, the 5-digit number, 15234, is 1 through 5 pandigital. The product 7254 is unusual, as the identity, 39 × 186 = 7254, containing multiplicand, multiplier, and product is 1 through...

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project euler – Problem 31

November 8, 2011
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In England the currency is made up of pound, £, and pence, p, and there are eight coins in general circulation: 1p, 2p, 5p, 10p, 20p, 50p, £1 (100p) and £2 (200p). Read More: 299 Words Totally

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project euler – Problem 15

November 8, 2011
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project euler – Problem 15

Starting in the top left corner of a 2x2 grid, there are 6 routes (without backtracking) to the bottom right corner. How many routes are there through a 20x20 grid? Read More: 293 Words Totally

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project euler-Problem 43

November 7, 2011
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The number, 1406357289, is a 0 to 9 pandigital number because it is made up of each of the digits 0 to 9 in some order, but it also has a rather interesting sub-string divisibility property. Let d1 be the 1st digit, d2 be the 2nd digit, and so on. In this way, we note the...

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project euler-Problem 41

November 7, 2011
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We shall say that an n-digit number is pandigital if it makes use of all the digits 1 to n exactly once. For example, 2143 is a 4-digit pandigital and is also prime. What is the largest n-digit pandigital prime that exists? Read More: 288 Words Totally

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Project Euler-Problem 38

November 1, 2011
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Take the number 192 and multiply it by each of 1, 2, and 3: 192 × 1 = 192 Read More: 450 Words Totally

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Machine Learning Ex 5.2 – Regularized Logistic Regression

October 25, 2011
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Machine Learning Ex 5.2 – Regularized Logistic Regression

Now we move on to the second part of the Exercise 5.2, which requires to implement regularized logistic regression using Newton's Method. Plot the data:

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Machine Learning Ex 5.1 – Regularized Linear Regression

October 25, 2011
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Machine Learning Ex 5.1 – Regularized Linear Regression

The first part of the Exercise 5.1 requires to implement a regularized version of linear regression. Adding regularization parameter can prevent the problem of over-fitting when fitting a high-order polynomial. Read More: 194 Words Totally

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Machine Learning Ex4 – Logistic Regression

October 24, 2011
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Machine Learning Ex4 – Logistic Regression

Exercise 4 required implementing Logistic Regression using Newton's Method. The dataset in use is 80 students and their grades of 2 exams, 40 students were admitted to college and the other 40 students were not. We need to implement a binary classification model to estimates college admission based on the student's scores on...

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ggplot2 Version of Figures in “25 Recipes for Getting Started with R”

August 16, 2011
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ggplot2 Version of Figures in “25 Recipes for Getting Started with R”

In order to provide an option to compare graphs produced by basic internal plot function and ggplot2, I recreated the figures in the book, 25 Recipes for Getting Started with R, with ggplot2. The code used to create the images is in separate paragraphs, allowing easy comparison. Read...

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