;+ ; NAME: ; GLITCH ; ; PURPOSE: ; Looks for "glitches" in the data by calculating the changes ; in count rate across a major frame. When it finds a major ; frame with a "glitch", its bin number is added to a list. ; ; CATEGORY: ; Data Analysis. ; ; CALLING SEQUENCE: ; ; BIN_LIST = GLITCH( Cts, [, Nglitch, CUT=Cut, /ZERO_ONLY, /NOWARN] ) ; ; INPUTS: ; Cts: Array containing the data, [float( nbin )]. ; ; OPTIONAL INPUTS: ; ; Nglitch: Number of bins with glitches, [integer]. ; ; OPTIONAL KEYWORD INPUTS: ; ; CUT: The cutoff fractional derivative used to determine if the ; counts in a bin is a glitch, [float]. ; ; ZERO_ONLY: Only look for zero bins in the Cts array. ; ; NOWARN: Suppress printing of warning messages. ; ; LOG: Write warning messages to log file. ; ; OUTPUTS: ; This function returns a list of bins where glitches have been found. ; ; EXAMPLE: ; Let's say you have an array of counts and want to find which ; bins have glitches: ; ; Cts = randomu( seed, 128 ) + 100 ; Cts(20) = 5000 ; Cts(90) = 0 ; ; list = GLITCH( Cts ) ; print, list ; ; MODIFICATION HISTORY: ; Written by: Han Wen, May, 1994. ; 20-JUL-1994 Bugfix: moved the min. 3 data pts cutoff to after ; the check for 0 bins. ; 10-JAN-1995 Bugfix: (nNOzero eq 0) -> (nNOzero le 1) because ; we need at least 2 points to determine the ; count derivative ;- function GLITCH, Cts, Nglitch, CUT=cut, ZERO_ONLY=zero_only, NOWARN=nowarn, LOG=log ON_ERROR,2 NP = N_PARAMS() if (NP lt 1) or (NP gt 2) then \$ message, 'Must be called with 1-2 parameters: Cts [, Nglitch]' nover = 0 & nzero = 0 if not keyword_set( CUT ) then cut = 2.0 if cut lt 0 then message,'Keyword CUT must be > 0 nbin = N_ELEMENTS( Cts ) ; First check for 0 bins; these are definitely glitches i_zero = WHERE( cts eq 0, nzero ) i_NOzero = WHERE( cts gt 0, nNOzero ) if (keyword_set( ZERO_ONLY )) or (nNOzero le 1) then goto, COLLECT ; Abort if there are too few data points to search for derivative glitches if nbin le 3 then begin printdev,'Not enough data points to determine glitches.',\$ NODISPLAY=nowarn, LOG=log goto, QUIT endif ; Calculate the derivatives at each bin and find the bin(s) with glitches Cts0 = Cts( i_NOzero ) cts_prev = shift( cts0, 1 ) diff = cts0 - cts_prev fder = diff/cts_prev fder(0) = -diff(1)/cts0(1) ; reverse defn for first point i_over = WHERE( abs( fder ) gt cut, nover ) ; Create the list of bad bins and return them COLLECT: nglitch = nzero + nover if nglitch gt 0 then begin badbins = intarr( nglitch ) if nzero gt 0 then \$ badbins(0 :nzero-1) = i_zero if nover gt 0 then \$ badbins(nzero:nzero+nover-1) = i_NOzero( i_over ) if (nzero gt 0) and (nover gt 0) then \$ badbins = badbins( SORT( badbins ) ) endif else badbins = -1 return, badbins QUIT: nglitch = 0 return, -1 end