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http://www.hyphy.org/cgi-bin/hyphy_forums/YaBB.pl Methodology Questions >> How to >> correct syntax for global parameters http://www.hyphy.org/cgi-bin/hyphy_forums/YaBB.pl?num=1152553546 Message started by Jennifer Knies on Jul 10^th, 2006 at 10:45am

Title: correct syntax for global parameters
Post by Jennifer Knies on Jul 10^th, 2006 at 10:45am

Hi,
In my batch file, I want to set alpha equal to some value, yet still have a "global" alpha. When I use the following syntax:

global alpha = 0.2289;

HYPHY estimates alpha (which I don't want it to do). If I instead have:

alpha = 0.2289;

HYPHY does not estimate alpha (good), but I am not sure if I have inadvertently made alpha local or is it still global. Thanks,
Jen

Title: Re: correct syntax for global parameters
Post by Sergei on Jul 10^th, 2006 at 10:51am

Dear Jen,

The correct syntax for what you want to do is either

Code (]
global alpha := 0.2289;
[/code):

or

[code]
global alpha;
alpha := 0.2289;

Note the use of the 'assign' operator (':=') to impose a constraint on alpha.

If you use,
[code]
alpha = 0.2289;
[/code]
then most likely alpha is made into a local variable and optimized (which you do not want), or simply ignored, if it's dependancy can't be followed from the model definition (which you also don't want).

Cheers,
Sergei