fix typo in weighted distances

fixes #38

Author: KristofferC

README.md

@@ -123,31 +123,31 @@ This type system has practical significance. For example, when computing pairwis
 
 Each distance corresponds to a distance type. The type name and the corresponding mathematical definitions of the distances are listed in the following table.
 
-| type name            |  convenient syntax   | math definition     |
-| -------------------- | -------------------- | --------------------|
-|  Euclidean           |  euclidean(x, y)     | sqrt(sum((x - y) .^ 2)) |
-|  SqEuclidean         |  sqeuclidean(x, y)   | sum((x - y).^2) |
-|  Cityblock           |  cityblock(x, y)     | sum(abs(x - y)) |
-|  Chebyshev           |  chebyshev(x, y)     | max(abs(x - y)) |
-|  Minkowski           |  minkowski(x, y, p)  | sum(abs(x - y).^p) ^ (1/p) |
-|  Hamming             |  hamming(x, y)       | sum(x .!= y) |
-|  Rogers-Tanimoto     |  rogerstanimoto(x, y)| 2(sum(x&!y) + sum(!x&y)) / (2(sum(x&!y) + sum(!x&y)) + sum(x&y) + sum(!x&!y)) |
-|  Jaccard             |  jaccard(x, y)       | 1 - sum(min(x, y)) / sum(max(x, y)) |
-|  CosineDist          |  cosine_dist(x, y)   | 1 - dot(x, y) / (norm(x) * norm(y)) |
-|  CorrDist            |  corr_dist(x, y)     | cosine_dist(x - mean(x), y - mean(y)) |
-|  ChiSqDist           |  chisq_dist(x, y)    | sum((x - y).^2 / (x + y)) |
-|  KLDivergence        |  kl_divergence(x, y) | sum(p .* log(p ./ q)) |
-|  JSDivergence        |  js_divergence(x, y) | KL(x, m) / 2 + KL(y, m) / 2 with m = (x + y) / 2 |
-|  SpanNormDist        |  spannorm_dist(x, y) | max(x - y) - min(x - y ) |
-|  BhattacharyyaDist   |  bhattacharyya(x, y) | -log(sum(sqrt(x .* y) / sqrt(sum(x) * sum(y))) |
-|  HellingerDist       |  hellinger(x, y)     | sqrt(1 - sum(sqrt(x .* y) / sqrt(sum(x) * sum(y)))) |
+| type name            |  convenient syntax       | math definition     |
+| -------------------- | ------------------------ | --------------------|
+|  Euclidean           |  euclidean(x, y)         | sqrt(sum((x - y) .^ 2)) |
+|  SqEuclidean         |  sqeuclidean(x, y)       | sum((x - y).^2) |
+|  Cityblock           |  cityblock(x, y)         | sum(abs(x - y)) |
+|  Chebyshev           |  chebyshev(x, y)         | max(abs(x - y)) |
+|  Minkowski           |  minkowski(x, y, p)      | sum(abs(x - y).^p) ^ (1/p) |
+|  Hamming             |  hamming(x, y)           | sum(x .!= y) |
+|  Rogers-Tanimoto     |  rogerstanimoto(x, y)    | 2(sum(x&!y) + sum(!x&y)) / (2(sum(x&!y) + sum(!x&y)) + sum(x&y) + sum(!x&!y)) |
+|  Jaccard             |  jaccard(x, y)           | 1 - sum(min(x, y)) / sum(max(x, y)) |
+|  CosineDist          |  cosine_dist(x, y)       | 1 - dot(x, y) / (norm(x) * norm(y)) |
+|  CorrDist            |  corr_dist(x, y)         | cosine_dist(x - mean(x), y - mean(y)) |
+|  ChiSqDist           |  chisq_dist(x, y)        | sum((x - y).^2 / (x + y)) |
+|  KLDivergence        |  kl_divergence(x, y)     | sum(p .* log(p ./ q)) |
+|  JSDivergence        |  js_divergence(x, y)     | KL(x, m) / 2 + KL(y, m) / 2 with m = (x + y) / 2 |
+|  SpanNormDist        |  spannorm_dist(x, y)     | max(x - y) - min(x - y ) |
+|  BhattacharyyaDist   |  bhattacharyya(x, y)     | -log(sum(sqrt(x .* y) / sqrt(sum(x) * sum(y))) |
+|  HellingerDist       |  hellinger(x, y)         | sqrt(1 - sum(sqrt(x .* y) / sqrt(sum(x) * sum(y)))) |
 |  Mahalanobis         |  mahalanobis(x, y, Q)    | sqrt((x - y)' * Q * (x - y)) |
 |  SqMahalanobis       |  sqmahalanobis(x, y, Q)  |  (x - y)' * Q * (x - y)  |
-|  WeightedEuclidean   |  euclidean(x, y, w)      | sqrt(sum((x - y).^2 .* w))  |
-|  WeightedSqEuclidean |  sqeuclidean(x, y, w)    | sum((x - y).^2 .* w)  |
-|  WeightedCityblock   |  cityblock(x, y, w)      | sum(abs(x - y) .* w)  |
-|  WeightedMinkowski   |  minkowski(x, y, w, p)   | sum(abs(x - y).^p .* w) ^ (1/p)  |
-|  WeightedHamming     |  hamming(x, y, w)        | sum((x .!= y) .* w)  |
+|  WeightedEuclidean   |  weuclidean(x, y, w)     | sqrt(sum((x - y).^2 .* w))  |
+|  WeightedSqEuclidean |  wsqeuclidean(x, y, w)   | sum((x - y).^2 .* w)  |
+|  WeightedCityblock   |  wcityblock(x, y, w)     | sum(abs(x - y) .* w)  |
+|  WeightedMinkowski   |  wminkowski(x, y, w, p)  | sum(abs(x - y).^p .* w) ^ (1/p)  |
+|  WeightedHamming     |  whamming(x, y, w)       | sum((x .!= y) .* w)  |
 
 **Note:** The formulas above are using *Julia*'s functions. These formulas are mainly for conveying the math concepts in a concise way. The actual implementation may use a faster way.