F

E-FILE, IN OUT or BOTH please
LAS, FILE command. The first argument is incorrect (typing error).

E-FILE, No default is provided for the file name
LAS, FILE command. The second argument (file name) is missing.

I-FIND, <Integer> observations found
LAS, FIND command, information message.

E-FIND, Nothing found
LAS, FIND command, information message. Variable FOUND is reset to 0.
User action : if you believe something should have been found, check the various selection criteria. One is probably different from what you had in mind.

I-FIND, <Integer> observations in index
LAS, FIND command with argument APPEND, information message. The index has been appended and compressed to avoid duplicate entries to a given scan.

W-FITCONT, Solution not converged
W-FITGAUSS, Solution not converged
W-FITNH3, Solution not converged
W-FITSHELL, Solution not converged
ANALYSE, GAUSS command. The minimization failed to converge to a valid solution.
User action : Look at the results using command FIT. If they seem good enough, use command ITERATE until convergence is reached. If the warning persists, may be the problem is badly defined and the solution unreliable.

E-FITNH3, Unit X must be Velocity
LAS, GAUSS command for method NH3. The X unit must be velocity to fit NH$_3$ hyperfine structure.
User action : use command SET UNIT X V, reset new guesses using command LINES and retry.

E-FITSHELL, No baseline removed
ANALYSE, GAUSS command, SHELL method. A base line must have been removed before fitting.
User action : use the BASE command to remove a baseline, and retry.

E-FITSHELL, Unit X must be Frequency
ANALYSE, GAUSS command, SHELL method. ``Circumstellar shells'' like profile fitting is only possible in Frequency units.
User action : use command SET UNIT X F, check the initial guesses and retry.

F-FIX, Current index is full
LAS, FIND command, usually with APPEND argument. Too many spectra match the current selection criteria, and the index is too large. Some spectra have been omitted from the index.
User action : Restrict the search by adding more severe selection criteria. Note in any case that you will have troubles processing the connected input file because it contains too many spectra. It would be wise to split this file in smaller ones, according to selected criteria.

E-FIX, More than <Integer> observations found
LAS, GET or other commands involving index finding operations, such as DROP. There are too many scans matching the requested criteria. Most likely, this error is due to an incoherent input file which contains twice the same scan (number AND version).
User action : It is possible to get rid of the duplicate scans by the following recipe. i) define a new output file to receive the valid spectra. ii) use a FIND/ALL without any selection criterium. iii) use the GET NEXT command to retrieve scans. iv) use the WRITE command for all scans but the duplicate scans that you should either skip or write under a new scan number (WRITE Number command). The new output file should be correct. If not see ``Recovering Corrupted Data Files''.

E-FIX, Read error
LAS, FIND or other commands involving index finding operations. This may be due to a lack of input file (not all commands are explicitly protected against this specific mistake), but also to hardware problems.
User action : after checking for the input file, retry the operation. If the error persists, submit an SPR, and see ``Recovering Corrupted Data Files''

W-FOLD, Cannot fold a single phased spectrum
LAS, FOLD command. The current spectrum was not observed in frequency switching mode, so that it cannot be folded.

E-FOLD, No channels left in spectrum
LAS, FOLD command. The align mode is INTERSECT, and the frequency switch is so large that no channel overlap from one phase to the others.
User action : Set the align mode to COMPOSITE, and redo the command.

E-FSHELL, Wrong Arguments : <Real>
ANALYSE, GAUSS command with method SHELL. The minimization routines went into a forbidden region for the parameters. The minimization aborts.
User action : retry the fit with a different choice of input parameters.