On Saturday, 1 April 2023 at 22:48:46 UTC, Ali Çehreli wrote:
On 4/1/23 15:30, Paul wrote:
> Is there a way to verify that it split up the work in to
tasks/threads
> ...?
It is hard to see the difference unless there is actual work in
the loop that takes time.
I always use the Rowland Sequence for such experiments. At least
it's better than the Fibonacci Range:
```d
struct RowlandSequence {
import std.numeric : gcd;
import std.format : format;
import std.conv : text;
long b, r, a = 3;
enum empty = false;
string[] front() {
string result = format("%s, %s", b, r);
return [text(a), result];
}
void popFront() {
long result = 1;
while(result == 1) {
result = gcd(r++, b);
b += result;
}
a = result;
}
}
enum BP {
f = 1, b = 7, r = 2, a = 1, /*
f = 109, b = 186837516, r = 62279173, //*/
s = 5
}
void main()
{
RowlandSequence rs;
long start, skip;
with(BP) {
rs = RowlandSequence(b, r);
start = f;
skip = s;
}
rs.popFront();
import std.stdio, std.parallelism;
import std.range : take;
auto rsFirst128 = rs.take(128);
foreach(r; rsFirst128.parallel)
{
if(r[0].length > skip)
{
start.writeln(": ", r);
}
start++;
}
} /* PRINTS:
46: ["121403", "364209, 121404"]
48: ["242807", "728421, 242808"]
68: ["486041", "1458123, 486042"]
74: ["972533", "2917599, 972534"]
78: ["1945649", "5836947, 1945650"]
82: ["3891467", "11674401, 3891468"]
90: ["7783541", "23350623, 7783542"]
93: ["15567089", "46701267, 15567090"]
102: ["31139561", "93418683, 31139562"]
108: ["62279171", "186837513, 62279172"]
*/
```
The operation is simple, again multiplication, addition,
subtraction and module, i.e. So four operations but enough to
overrun the CPU! I haven't seen rsFirst256 until now because I
don't have a fast enough processor. Maybe you'll see it, but the
first 108 is fast anyway.
**PS:** Decrease value of the `skip` to see the entire sequence.
In cases where your processor power is not enough, you can create
skip points. Check out BP...
SDB@79
