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 # Description
 **English**
 ## Purpose
 The program shows how fast a CPU is. How fast it looks depends on how the
 program is written, so the number is a measure of the CPU and the code
 together, not of the CPU alone.
 ## What it does
 It tests every number from 0 to 1,000,000 with `is_prime_avx2`, which uses
 AVX2 trial division by 6k ± 1 (four divisors per step). It prints each prime
 on its own line and writes a summary line to standard error:
 ```text
 Found 78498 primes from 0 to 1000000 in 13.806 ms
 ```
 78,498 is the known count of primes up to 1,000,000, so the summary line also
 works as a correctness check.
 ## Why the time depends on the code
 The same CPU gives very different times for different programs:
 - the algorithm (trial division, a sieve, a segmented sieve),
 - the instruction set used (scalar code, AVX2, AVX-512),
 - compiler and flags (`-O3 -mavx2`, MSVC `/O2 /arch:AVX2`),
 - what is measured (only the search, or also printing to a console).
 Here only the search is timed. Output is collected first and printed
 afterwards, so console speed does not change the number.