cdm/src/main/java/ucar/unidata/io/Swap.java
static public double swapDouble(double v) {
        long l = swapLong(Double.doubleToLongBits(v));
        return (Double.longBitsToDouble(l));
    }
static public double swapDouble(double v) {
        long l = swapLong(Double.doubleToLongBits(v));
        return (Double.longBitsToDouble(l));
    }
Returns the double resulting from reversing 8 bytes of a specified
double.

@param  v       input value for which byte reversal is desired
@return         the value represented by the bytes of <code>v</code>
reversed