Dear Matthias,
Thank you for your answer. But I think I did not made myself clear.
I used the same input file , and ran it twice with alps 1.35 obtaining different results in each run. Using the same input file and running twice with alps 2.00.rc4 I got different results. All 4 results were different from each other.
I could not obtain exactly the same results even using the same code and the same SEED in either versions. Am I doing something wrong? Or the result could never actually be the same?
In case it helps, this is the input file used in all runs: FILE:parameter
LATTICE="simple cubic lattice" MODEL = "spin" ALGORITHM="sse" MEASURE[Structure Factor]=false MEASURE[Correlations]=false MEASURE[Specific Heat]=true MEASURE[Stiffness]=true MEASURE[Magnetization]=true WHICH_LOOP_TYPE="locopt" EPSILON=0.5 local_S=1 J=-1 J0=-1 J1=-1 Jz=0 Jz'=0 {THERMALIZATION=10000;L=04;BETA=0.10;SWEEPS=1000;D=10.0;SEED=814}
I converted it with parameter2xml
Then I executed the dirloop_see v1.1 for alps 1.3.5: dirloop_sse --Tmin=10 parameter.in.xml
with the result: ... <SCALAR_AVERAGE name="Energy"> <COUNT>8519</COUNT> <MEAN method="simple">250.472</MEAN> ... Then I repeated the command: dirloop_sse --Tmin=10 parameter.in.xml
and obtained the result: ... <SCALAR_AVERAGE name="Energy"> <COUNT>3009</COUNT> <MEAN method="simple">250.553</MEAN> ...
The same goes for the dirloop 4.1 based on alps 2.0.0rc4 code: same parameters same SEED:
After extracting values with "convert2xml parameter.task1.out.run1" the 1st run produced: <SCALAR_AVERAGE name="Energy"> <COUNT>1473</COUNT> <MEAN method="simple">251.784</MEAN>
And in the 2nd run: <SCALAR_AVERAGE name="Energy"> <COUNT>16076</COUNT> <MEAN method="simple">250.616</MEAN>
Marcelo Guimarães
2012/1/21 Matthias Troyer troyer@phys.ethz.ch
Hi Marcello,
Indeed if the same SEED is used you get the same results if the same code is taken. However, dirloop_sse was completely rewritten between 1.3 and 2.0. It is a new code. Thus the results should now only agree within error bars.
Matthias
On Jan 20, 2012, at 6:56 PM, Marcelo Guimarães wrote:
Dear All,
I was wondering if using the same SEED parameter with the dirloop_sse
application in different runs should produce exactly the same results.
It is defined as " The random number seed used in the next run.". But I
failed to produce the same results with alps 1.35 or with alps 2.02.
Regards,
Marcelo Guimarães