Hi, suppose I have :
1)first.rs calls function "first"
2)second.rs calls function "second"
3)firstAndSecond.rs calls function "first" followed by function "second"
Then I would expect (ignoring "startup" times) that:
TimeToRun( firstAndSecond.rs) = TimeToRun( first.rs) + TimeToRun( second.rs)
However instead I find that :
TimeToRun( firstAndSecond.rs) > TimeToRun( first.rs) + TimeToRun( second.rs)
Specifically :
TimeToRun( first.rs) = real 0m2.631s
TimeToRun( second.rs) = real 0m5.739s
TimeToRun( firstAndSecond.rs) = real 0m23.856s
I cannot quite work out why this might be the case (and I dont think it is
to do with startup times). Note I compile the programs as follows :
rustc first.rs
rustc second.rs
rustc firstAndSecond.rs
Note that when you profile the programs, "firstAndSecond" looks a bit
strange in that there are library calls which are absent when one profiles
first or second.
The programs are given below :
********************************************************************************
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//first.rs
static g_r: float = 3.569956;
static g_x0:float = 0.53;
fn first(n: i64, x0 : float, r: float) -> float {
let mut x = x0;
let mut i = 0i64;
loop {
x = r*x*(1.-x);
i += 1;
if i == n { break }
}
x
}
fn second(n: i64, x0 : float, r: float) -> float {
fn calc(x : float, r: float) -> float {
let mut xm = x;
xm = r*xm*(1.-xm);
xm
}
let mut x = x0;
let mut i = 0i64;
loop {
x = calc(x,r);
i += 1;
if i == n { break }
}
x
}
fn main(){
let l = 400000000i64;
let result = first(l,g_x0,g_r);
io::println(float::to_str(result));
}
********************************************************************************
********************************************************************************
********************************************************************************
********************************************************************************
//second.rs
static g_r: float = 3.569956;
static g_x0:float = 0.53;
fn first(n: i64, x0 : float, r: float) -> float {
let mut x = x0;
let mut i = 0i64;
loop {
x = r*x*(1.-x);
i += 1;
if i == n { break }
}
x
}
fn second(n: i64, x0 : float, r: float) -> float {
fn calc(x : float, r: float) -> float {
let mut xm = x;
xm = r*xm*(1.-xm);
xm
}
let mut x = x0;
let mut i = 0i64;
loop {
x = calc(x,r);
i += 1;
if i == n { break }
}
x
}
fn main(){
let l = 400000000i64;
let result = second(l,g_x0,g_r);
io::println(float::to_str(result));
}
********************************************************************************
********************************************************************************
********************************************************************************
********************************************************************************
//firstAndSecond.rs
static g_r: float = 3.569956;
static g_x0:float = 0.53;
fn first(n: i64, x0 : float, r: float) -> float {
let mut x = x0;
let mut i = 0i64;
loop {
x = r*x*(1.-x);
i += 1;
if i == n { break }
}
x
}
fn second(n: i64, x0 : float, r: float) -> float {
fn calc(x : float, r: float) -> float {
let mut xm = x;
xm = r*xm*(1.-xm);
xm
}
let mut x = x0;
let mut i = 0i64;
loop {
x = calc(x,r);
i += 1;
if i == n { break }
}
x
}
fn main(){
let l = 400000000i64;
let result = first(l,g_x0,g_r);
io::println(float::to_str(result));
let result = second(l,g_x0,g_r);
io::println(float::to_str(result));
}
********************************************************************************
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