Windows - Help with Java high-precision operation problems

Question

The company's projects required a lot of high-precision operations. At first, we used double-type operations. Later, we found that the accuracy of some values ​​exceeded the ideal range after using double-type operations, so we used BigDecimal to calculate. The current problem is the operation efficiency of BigDecimal. Dozens of times slower than double, the amount of data...

怪我咯 · Answer

Except for using C or C++ to do high-precision operations, there seems to be no way to take into account both performance and precision.

扔个三星炸死你 · Answer

There is a course called "Computational Methods" in the computer major of the university, which specifically discusses how to minimize errors in the calculation process with limited precision. If you are interested, you can find relevant teaching materials.

欧阳克 · Answer

Later I found that the accuracy of some values after using double type operations exceeded the ideal range
Is it exceeded or not satisfied?

Here is a piece of code for calculating square roots. I found it on stackoverflow. When tested on my own machine, it is about ten times faster than the one you have above.
So: Firstly, you can improve performance through improved algorithms. Secondly, the best way is to find some existing libraries and use them directly: such as the one listed above

public void test_sqrt() {
    BigDecimal x = BigDecimal.valueOf(Long.MAX_VALUE);
    BigDecimal x0 = BigDecimal.ZERO;
    BigDecimal x2 = new BigDecimal(2);
    BigDecimal x1 = new BigDecimal(Math.sqrt(x.doubleValue()));
    while (!x0.equals(x1)) {
        x0 = x1;
        x1 = x.pide(x0, 2000, BigDecimal.ROUND_HALF_UP);
        x1 = x1.add(x0);
        x1 = x1.pide(x2, 2000, BigDecimal.ROUND_HALF_UP);
    }
    assertEquals(3037000499L, x1.longValue());
}