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-rw-r--r--log_regress_pred.m22
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diff --git a/log_regress_pred.m b/log_regress_pred.m
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+function pred = log_regress_pred(price, quantity)
+
+ days = size(price, 1) - size(quantity, 1);
+ product_count = size(price, 2);
+ test_count = size(quantity, 1);
+ test_set = 1:test_count;
+ pred_set = test_count+1:size(price, 1);
+
+ pred = zeros(days, product_count);
+ for i = 1:product_count
+ [a,b] = regress_log(price(test_set, i), quantity(test_set, i));
+ pred(:, i) = a * log(price(pred_set, i)) + b;
+ end
+
+endfunction
+
+
+function [a,b] = regress_log(x, y)
+ ab = [ log(x) ones(length(x), 1) ] \ y;
+ a = ab(1);
+ b = ab(2);;
+endfunction