On 11/04/2009, pste...@apache.org <pste...@apache.org> wrote: > Author: psteitz > Date: Sat Apr 11 15:30:02 2009 > New Revision: 764208 > > URL: http://svn.apache.org/viewvc?rev=764208&view=rev > Log: > Restored some double casts to improve ensure correctness does not depend on > order of operations or literal conversion, dropped uneccesary parens. > > Modified: > > commons/proper/math/trunk/src/java/org/apache/commons/math/stat/regression/SimpleRegression.java > > Modified: > commons/proper/math/trunk/src/java/org/apache/commons/math/stat/regression/SimpleRegression.java > URL: > http://svn.apache.org/viewvc/commons/proper/math/trunk/src/java/org/apache/commons/math/stat/regression/SimpleRegression.java?rev=764208&r1=764207&r2=764208&view=diff > > ============================================================================== > --- > commons/proper/math/trunk/src/java/org/apache/commons/math/stat/regression/SimpleRegression.java > (original) > +++ > commons/proper/math/trunk/src/java/org/apache/commons/math/stat/regression/SimpleRegression.java > Sat Apr 11 15:30:02 2009 > @@ -124,9 +124,9 @@ > } else { > double dx = x - xbar; > double dy = y - ybar; > - sumXX += dx * dx * n / (n + 1.0); > - sumYY += dy * dy * n / (n + 1.0); > - sumXY += dx * dy * n / (n + 1.0); > + sumXX += dx * dx * (double) n / (n + 1d); > + sumYY += dy * dy * (double) n / (n + 1d); > + sumXY += dx * dy * (double) n / (n + 1d);
AFAICT these casts are not necessary, regardless of order. See: http://java.sun.com/docs/books/jls/third_edition/html/conversions.html#5.6.2 Numeric promotion for binary operands (such as * and /) will always convert the other operand to double if one operand is double. > xbar += dx / (n + 1.0); > ybar += dy / (n + 1.0); > } > @@ -157,9 +157,9 @@ > if (n > 0) { > double dx = x - xbar; > double dy = y - ybar; > - sumXX -= dx * dx * n / (n - 1.0); > - sumYY -= dy * dy * n / (n - 1.0); > - sumXY -= dx * dy * n / (n - 1.0); > + sumXX -= dx * dx * (double) n / (n - 1d); > + sumYY -= dy * dy * (double) n / (n - 1d); > + sumXY -= dx * dy * (double) n / (n - 1d); Ditto > xbar -= dx / (n - 1.0); > ybar -= dy / (n - 1.0); > sumX -= x; > @@ -468,7 +468,7 @@ > */ > public double getInterceptStdErr() { > return Math.sqrt( > - getMeanSquareError() * ((1d / n) + (xbar * xbar) / sumXX)); > + getMeanSquareError() * ((1d / (double) n) + (xbar * xbar) / > sumXX)); Ditto. > } > > /** > @@ -589,7 +589,7 @@ > * @return the intercept of the regression line > */ > private double getIntercept(double slope) { > - return (sumY - slope * sumX) / (n); > + return (sumY - slope * sumX) / n; > } > > /** > > > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
