MathUtils.equals(double, double) does not work properly for floats
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Key: MATH-471
URL: https://issues.apache.org/jira/browse/MATH-471
Project: Commons Math
Issue Type: Bug
Reporter: Sebb
MathUtils.equals(double, double) does not work properly for floats.
There is no equals(float,float) so float parameters are automatically promoted
to double. However, that is not necessarily appropriate, given that the ULP for
a double is much smaller than the ULP for a float.
So for example:
{code}
double oneDouble = 1.0d;
assertTrue(MathUtils.equals(oneDouble, Double.longBitsToDouble(1 +
Double.doubleToLongBits(oneDouble)))); // OK
float oneFloat = 1.0f;
assertTrue(MathUtils.equals(oneFloat, Float.intBitsToFloat(1 +
Float.floatToIntBits(oneFloat)))); // FAILS
float f1 = 333.33334f;
double d1 = 333.33334d;
assertTrue(MathUtils.equals(d1, f1)); // FAILS
{code}
I think the equals() methods need to be duplicated with the appropriate changes
for floats to avoid any problems with the promotion of floats.
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