| Re: accesing variables defined in a higher program level [message #33943] |
Thu, 06 February 2003 09:57 |
Craig Markwardt
Messages: 1869
Registered: November 1996
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Senior Member |
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"Isa Usman" <eepisu@bath.ac.uk> writes:
> Hello,
>
> I am trying to get a function to use variable values that are defined in a
> higher level procedure. Since COMMON blocks can't be used in functions is
> there a way round this? here is an example of what i am trying to do;
As other readers have pointed out, you can use common blocks in
functions. But, that's still not the greatest programming practice.
For example, what if you end up needing a double integral? Common
blocks will not survive the nested call.
I have a function integrator on my web page named QPINT1D that allows
you to pass arbitrary data to the function via two methods. The first
method is to pass data in a structure. Obviously you can arrange the
structure any way you like. The second way is to pass the data using
keywords. This also involves passing in a structure, and then QPINT1D
uses the _EXTRA mechanism, which causes the named structure elements
to be converted to named keywords in the function call.
Good luck,
Craig
--
------------------------------------------------------------ --------------
Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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| Re: accesing variables defined in a higher program level [message #33947 is a reply to message #33943] |
Thu, 06 February 2003 08:53  |
R.Bauer
Messages: 1424
Registered: November 1998
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Senior Member |
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Isa Usman wrote:
> Hello,
>
> I am trying to get a function to use variable values that are defined in a
> higher level procedure. Since COMMON blocks can't be used in functions is
> there a way round this? here is an example of what i am trying to do;
>
> Pro high_level
> x=1
> y=1
> z=1
>
> I=integrate('f_x',z)
> end
>
> function integrate,z
> ........
> ........
> call function f_x
> i=........
> return,i
> end
>
> function f_x, z
> w=x+y+z
> return, w
> end
>
> Many thanks
>
> Isa
>
>
>
Dear Isa
I don't like common blocks but I am a bit surprised that they should not
work in functions. I can't believe this.
What is the reason for using all these call functions ?
Why did you not define
function f_x, x,y,z
w=x+y+z
return, w
and call this directly by high_level like
Pro high_level
x=1
y=1
z=1
I=f_x(x,y,z)
end
regards
Reimar
--
Reimar Bauer
Institut fuer Stratosphaerische Chemie (ICG-I)
Forschungszentrum Juelich
email: R.Bauer@fz-juelich.de
------------------------------------------------------------ -------
a IDL library at ForschungsZentrum Juelich
http://www.fz-juelich.de/icg/icg-i/idl_icglib/idl_lib_intro. html
============================================================ =======
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| Re: accesing variables defined in a higher program level [message #33949 is a reply to message #33947] |
Thu, 06 February 2003 08:52 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Isa Usman (eepisu@bath.ac.uk) writes:
> I am trying to get a function to use variable values that are defined in a
> higher level procedure. Since COMMON blocks can't be used in functions is
> there a way round this? here is an example of what i am trying to do;
>
> Pro high_level
> x=1
> y=1
> z=1
>
> I=integrate('f_x',z)
> end
>
> function integrate,z
> ........
> ........
> call function f_x
> i=........
> return,i
> end
>
> function f_x, z
> w=x+y+z
> return, w
> end
What makes you think COMMON blocks can't be used in functions?
They can be used in functions, procedures, main-level programs,
and--in fact--anywhere in IDL.
Rearranging your code the way it will eventually be in a file
(if you want it to work, that is), why not something like this:
function f_x, z
COMMON data, x, y
w=x+y+z
return, w
end
function integrate, f_x, z
value = call_function(f_x, z)
print, value
return,value
end
Pro high_level
COMMON data, x, y
x=1
y=1
z=1
I=integrate('f_x', z)
end
--
David W. Fanning, Ph.D.
Fanning Software Consulting, Inc.
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
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