You've confused the different uses of scripting functions vs. Grads prompt functions. You can only display a variable that you have defined using the 'define ...' command (note the use of the quotes signaling that it was defined as if you typed it in at the Grads prompt). Your use of variable = satvap(...) with satvap being a script function only is causing Grads to assume variable is a script variable only, not one that can be displayed. The reason you get the other error when you put the other line in quotes is because math_exp is strictly a script version of the exp function that you would use in the Grads command prompt. Thus, you would want to change that line to<br>
<br>'es = 6.112*exp(17.67*temp/(temp+243.5))'<br><br>in order to display es or define any other variables that would depend on it.<br><br>Jeff Duda<br><br><div class="gmail_quote">On Thu, Mar 1, 2012 at 7:06 AM, Mike Manning <span dir="ltr"><<a href="mailto:michael@bsch.au.com">michael@bsch.au.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi everyone,<br>
<br>
I'm using data from the FNMOC model and am trying to make a function<br>
that calculates Lifted Index. I'm using bits of the code from the<br>
<a href="http://plotskew.gs" target="_blank">plotskew.gs</a> code. So far I've got the temperature (celsius) and<br>
dewpoint (celsius) worked out for each level. Now I'm calculating the<br>
parcel details.. I've pulled some of the functions and have just been<br>
testing to make sure I'm on the right track. If I have this code for<br>
example:<br>
<br>
'c'<br>
'reinit'<br>
'open gfs.00z.ctl'<br>
'set t 7'<br>
'set lon 135 155'<br>
'set lat -31 -10'<br>
<br>
'set lev 1000'<br>
't1000mb = TMPprs-273.14'<br>
'define dp1000mb =<br>
t1000mb-((14.55+0.114*t1000mb)*(1-0.01*RHprs)+pow((2.5+0.007*t1000mb)*(1-0.01*RHprs),3)+(15.9+0.117*t1000mb)*pow((1-0.01*RHprs),14))'<br>
<br>
variable = satvap2(t1000mb)<br>
<br>
'd variable'<br>
<br>
function satvap2(temp)<br>
<br>
*---------------------------------------------------------------<br>
* Given temp in Celsius, returns saturation vapor pressure in mb<br>
*---------------------------------------------------------------<br>
<br>
es=6.112*math_exp(17.67*temp/(temp+243.5))<br>
<br>
return(es)<br>
'quit'<br>
<br>
<br>
<br>
it complains about an error? If I put the code in the satvap2 function<br>
in single quotes it then says "math_exp" is not a variable or function"?<br>
I'm a little lost on how to fix this one up if it's possible.<br>
<br>
Cheers, Mike<br>
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</blockquote></div><br><br clear="all"><br>-- <br>Jeff Duda<br>Graduate research assistant<br>University of Oklahoma School of Meteorology<br>Center for Analysis and Prediction of Storms<br><br>