# Re: [ferret_users] Co relation coefficient.

You need to precise the data of each variable (because you use different data) :
let p = pottmp[y=35,d=1]
let q = temperature[y=35,d=2]
(or switch d=1 and d=2, and don't know which of your data contains the variables)

2015-05-27 17:23 GMT+08:00 Satyam Srivastava :

yes? set mode metafile
yes? set data pottm2008.nc
yes? set data pottmp.2008.nc
yes? let p = pottmp[y=35]
yes? let q = temperature[y=35]
yes? go variance
... Variance and Covariance: Instructions:
Use the LET/QUIET command to define the variable(s) P (and Q) as
your variable(s) of interest (e.g. yes? LET/QUIET P = u[x=180,y=0])
The variance of P will be variable P_VAR  (Q --> Q_VAR)
The covariance will be COVAR The correlation will be CORREL.
Type GO VAR_N to obtain n/n+1 statistical correction factor
...
yes? go var_n
CANCEL MODE VERIFY
**ERROR: variable unknown or not in data set: TEMPERATURE[Y=35]
IF `nm1 eq 0` then exit/script
Command file, command group, or REPEAT execution aborted

On Wed, May 27, 2015 at 12:01 PM, samir pokhrel wrote:
Dear Satyam,

Make Sure that your p and q dimensions matches, it seems from your code that longitude of p vary from 0:30N and that of q from 0 to 1N. Please correct it and verify

Regards
Samir

On Wed, May 27, 2015 at 11:39 AM, Satyam Srivastava wrote:
Hi Folks,

I am trying to calculate the co relation coefficient for two different data set I have already gone through the ferret FAQ, from there i got the idea to compute for a single data set can any one help me for two different data set on different grids and they are time series data.

as i am trying the same concept but i am getting the errors as follows:

yes? set mode metafile
yes? use pottm2008.nc
yes? use pottmp.2008.nc
yes? let p=temperature[x=0:30,y=0:35]
yes? let q=pottmp[x=0:1,y=0:35]
yes? go var_n
CANCEL MODE VERIFY
**ERROR: variable unknown or not in data set: MASK_PQ
IF `nm1 eq 0` then exit/script
Command file, command group, or REPEAT execution aborted
yes?

--
Regards,

Satyam Srivastava,
J.R.F,
K. Banerjee Centre of Ocean Sciences,
+918756123444

--
Samir Pokhrel
Climate and Global Modelling Division
Indian Institute of Tropical Meteorology
NCL Post, Pashan
Pune-411008
INDIA

--
Regards,

Satyam Srivastava,
J.R.F,
K. Banerjee Centre of Ocean Sciences,
+918756123444

--
----------------------------------------------------
Nicolas Freychet
Postdoc Reseach Fellow at RCEC