The OPAL Discussion Forum

[Christof Metzger-Kraus <christof.j.kraus AT gmail.com>]

Hi Bettina,

the lack of support of SEED=-1 doesn't mean that you have to do this manually. Add

SYSTEM, "python gen_seed.py";

to the end and

CALL, "gen_seed.opal";

somewhere at the begin of your input file and add the two files in the attachment to the directory where you run this input file.

Hope, that this helps. It worked for me, but I only tested it with a simple (BerlinPro) input file.

christof

On Wed, Mar 25, 2020 at 11:03 AM Frey Matthias (PSI) <matthias.frey AT psi.ch> wrote:

Dear Bettina,

The SEED in the Sampler is different to the SEED used for the particle distribution, which the manual refers to (I think).

So, if you use SEED=-1 for the particle distribution, OPAL takes the time. If you use the SEED=-1 for the sampler,

it doesn't take the time to generate the samples.

Best,

Matthias

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Von: opal-request AT lists.psi.ch <opal-request AT lists.psi.ch> im Auftrag von Kuske, Bettina <bettina.kuske AT helmholtz-berlin.de>
Gesendet: Mittwoch, 25. März 2020 10:16:17
An: opal AT lists.psi.ch
Betreff: [Opal] Error in option seed

 

Dear developers,

I am using the seed option.

Refering to the manual, SEED=-1 uses the time as seed,

so to my understanding, each run of the same sampler file should

have a different seed and thus different samples.

This doesn't seem to work.

I ran a sampler file twice with SEED=-1 with only one variable.

Each time I start the run, I get identical solenoid settings.

// Sampling methods
SM1: SAMPLING, VARIABLE="sol",  TYPE="UNIFORM",  SEED=-1, RANDOM=TRUE, N=2;

I can work around by setting theseed manually, but that should be fixed, or the manual adapted.

Thank you!

Bettina

---

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#!/bin/env python

import datetime
import sys
import math
import struct

def main(argv):
    fh = open('gen_seed.opal', 'w')
    now = datetime.datetime.now()

    timestamp = datetime.datetime.now().timestamp() * math.pow(10, 9)
    itimestamp = struct.unpack('!Q', struct.pack('!d', timestamp))[0]
    timestamp = datetime.datetime(now.year, now.month, now.day).timestamp() * math.pow(10, 9)
    itimestamp = itimestamp - struct.unpack('!Q', struct.pack('!d', timestamp))[0]
    sitimestamp = (itimestamp >> 25) << 25
    itimestamp = itimestamp - sitimestamp

    fh.write('REAL genseed = %d;\n' % itimestamp)

    fh.close()

if __name__ == "__main__":
    main(sys.argv[1:])

Attachment: gen_seed.opal
Description: Binary data