Pass Array to Subroutine IDL -


i have long lookup table (~40,000 lines) using code. currently, have set grab 4 arrays lookup table in subroutine uses it, call subroutine ~3,000 times. rather not waste processing time grabbing table arrays repeatedly. there way grab them in main program, store them, , source them later in subroutine?

my current code grabs lookup table in 4 separate arrays of 39,760 lines, , calling this:

readcol, 'lookuptable2.txt', f='d,d,d,d',albedo, inertia, nightt, dayt

edit: should note have idl 6.2, if there way in newer version, still appreciate knowing how.

edit 2: current program has function saves 4 arrays , executes main function. can call function arrays argument? way wouldn't have keep creating same array

something like:

pro   func(array1, array2, var1, var2, var3) end

there several ways can this.

it looks have 4 columns , 40,000 lines, correct?

then can following. first, assume there no header data in ascii file following commands.

function read_my_file,file_name  ;;  assume file_name full path , including file name extension fname = file_name[0] ;;  1 find file following ;;    fname = file_search([path file],[file name extension])  ;;  define number of lines in file nl = file_lines(fname[0]) ;;  define empty arrays fill col1 = dblarr(nl[0]) col2 = dblarr(nl[0]) col3 = dblarr(nl[0]) col4 = dblarr(nl[0]) dumb = dblarr(4) ;;  open file openr,gunit,fname[0],error=err,/get_lun if (err ne 0) print, -2, !error_state.msg   ;;  prints error message n=0l, nl[0] - 1l begin   ;;  read in file data   readf,gunit,format='(4d)',dumb   ;;  fill arrays   col1[n] = dumb[0]   col2[n] = dumb[1]   col3[n] = dumb[2]   col4[n] = dumb[3] endfor ;;  close file free_lun,gunit ;;  define output output = [[col1],[col2],[col3],[col4]]  ;;  return calling routine return,output end

note work better if provide explicit width format statement, e.g., '(4d15.5), means 15 character input 5 decimal places.

this return col1 through col4 user or calling routine [n,4]-element array, e.g., col1 = output[*,0]. use structure each tag contains 1 of colj arrays or return them through keywords.

then can pass these arrays function/program in following way:

pro my_algorithm_wrapper,file_name,results=results ;;  data files columns = read_my_file(file_name) ;;  pass data [algorithm] function results = my_algorithm(columns[*,0],columns[*,1],columns[*,2],columns[*,3]) ;;  return user return end

to call command line (after making sure both routines compiled), following:

idl> my_algorithm_wrapper,file_name,results=results idl> help,results    ;;  see function my_algorithm.pro returned

the above code should work idl 6.2.

general notes

  1. try avoid using uppercase letters in idl routine names can cause issues when idl searches routine during call or compilation statement.
  2. you need name program/function in line pro/function statement @ beginning of file. name must come after pro/function statement.
  3. it wise use explicit formatting statements avoid ambiguities/errors when reading data files.
  4. you can pass variable type (e.g., scalar integer, array, structure, object, etc.) programs/functions long handled appropriately within program/function.

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