The OPAL Discussion Forum

["Snuverink Jochem (PSI)" <jochem.snuverink AT psi.ch>]

Dear Simon,

I think there is unfortunately no better way to do it.

As you noticed, 'apert1' is still interpreted as a string (without quotes it is converted to uppercase), and not as a variable.

See also http://amas.web.psi.ch/opal/Documentation/master/OPAL_Manual.html#sec.format.label and http://amas.web.psi.ch/opal/Documentation/master/OPAL_Manual.html#sec.format.astring

Cheers, Jochem

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From: opal-request AT lists.psi.ch <opal-request AT lists.psi.ch> on behalf of Simon Friederich <s.friederich AT uni-mainz.de>
Sent: Wednesday, April 1, 2020 1:26:27 PM
To: opal AT lists.psi.ch
Subject: [Opal] String variable for aperture

 

Dear all,

As we have changing apertures throughout our beamline I'd really like to use string variables but I don't get the correct syntax. I want something like:

STRING apert1 = "circle(0.015)"
STRING apert2 = "circle(0.030)"

drift1: DRIFT, ELEMEDGE=0.5, APERTURE=apert1, L=0.5;
drift2: DRIFT, ELEMEDGE=1, APERTURE=apert2, L=0.5;

But the error appears
Error> *** User error detected by function "OpalElement::getApert()"
Error>     Unknown aperture type 'APERT1'.
Error>     Unknown aperture type 'APERT1'.

Do I miss something?

Best regards
Simon

P.S.: I know this workaround does it
REAL napert1 = 0.015;
REAL napert2 = 0.030;

drift1: DRIFT, ELEMEDGE=0.5, APERTURE="circle(" & STRING(napert1) & ")", L=0.5;
drift1: DRIFT, ELEMEDGE=1, APERTURE="circle(" & STRING(napert2) & ")", L=0.5;

But maybe there is a better way to do it.

-- 
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Dr. Simon Friederich
Helmholtz-Institut Mainz
Kollaboration B / ACID
Johannes Gutenberg-Universität Mainz
Staudingerweg 18
55128 Mainz, Deutschland

Tel.: +49 (0)6131 39-23160
E-Mail: s.friederich AT uni-mainz.de
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