Slug #1722
Daft slug
Description
Since I'm now working for "the other side", I can send lots of bug reports ;-)
use R999 ::= QQ[x[1..999]]; I := ideal([y^2 | y in indets(R999)]); Q := R999/I; use Q; J := 0; t0 := CpuTime(); J := sum([x[k] | k in 1..9])^10; TimeFrom(t0); ---> SLOWER J := 0; t0 := CpuTime(); J := sum([x[k] | k in 1..9])^100; TimeFrom(t0); ---> FASTER (huh?)
History
#1 Updated by John Abbott over 1 year ago
This not really serious, just unexpected/surprising.
JAA does not really think that there is anything to fix here.
#2 Updated by John Abbott over 1 year ago
- Status changed from New to In Progress
On my current linux box the timings are:
19.777 16.297
#3 Updated by Anna Maria Bigatti over 1 year ago
John Abbott wrote:
On my current linux box the timings are:
[...]
On my Mac
15.269 11.807
#4 Updated by Anna Maria Bigatti over 1 year ago
- % Done changed from 0 to 20
At least partly due to memory creation for intermediate computations: restarting CoCoA and swapping the computations I get
/**/ J := 0; t0 := CpuTime(); J := sum([x[k] | k in 1..9])^100; TimeFrom(t0); 13.190 /**/ J := 0; t0 := CpuTime(); J := sum([x[k] | k in 1..9])^10; TimeFrom(t0); 13.862
Notice also that this is effectively constant
/**/ f9 := sum([x[k] | k in 1..9]); /**/ J := 0; t0 := CpuTime(); J := f9^16; TimeFrom(t0); 11.532 /**/ J := 0; t0 := CpuTime(); J := f9^32; TimeFrom(t0); 11.552 /**/ J := 0; t0 := CpuTime(); J := f9^256; TimeFrom(t0); 11.579