compute_opersvarsfiles(values, varinfo)
  NOTE: Values from the first file (with always operation 'add')
  [prevalues]: values from the previous operations
  values= '%' separated list of dimension ranges and file,operation,variable to compute
    [dimranges1]@[operfile1var]%[dimranges2]@[operfile2var]%[...[dimrangesM]@[operfileMvar]]
    dimranges: ';' separated list of dimension, dimension-variable names and their ranges ('|' separated)
      [dim1]|[dimv1]|[range];[dim2]|[dimv2]|[range];[...|[dimN]|[dimvN]|[range]]
      with [range] as:
        -1, all the values
        -9, last values
        int, a single value
        [beg,end,frq], from a beginning to an end with a given frequency
    operfilevar: [oper]|[file]|[var] '|' separated list of triplets of [operation], [file], [variable name to use]
      * [oper]: operations (being [prevalues] the values computed until the operation)
        'add': adding [var] ([prevalues] + [var])
        'addc',[modval1]: add [modval1] to [prevalues]
        'arctan', arctangent [-p1, pi]
        'centerderiv',[N],[ord],[dim]: un-scaled center [N]-derivative of order [ord] along dimension [dim] of [var]
        'div': dividing by [var] ([prevalues] / [var])
        'divc',[modval1]: [prevalues] divide by [modval1]
        'forwrdderiv',[N],[ord],[dim]: un-scaled forward [N]-derivative of order [ord] along dimension [dim] of [var]
        'inv': inverting [prevalues] (1/[prevalues])
        'lowthres',[modval1],[modval2]: if [prevalues] < [modval1]; prevalues = [modval2]
        'lowthres@oper',[modval1],[oper],[modval2]: if [prevalues] < [modval1]; prevalues = [oper] (operation as [modval2])
        'mul': multiplying by [var] ([prevvalues] * [var])
        'mulc',[modval1]: [prevalues] multiplied by [modval1]
        'norm_meanminmax',[NOTnormdims]: normalization of data as: (val-)/(max(val)-min(val)) except along
          dimensions [NOTnormdims] (':' list of dimension names, or 'any' for using all dimensions)
        'norm_minmax',[NOTnormdims]: normalization of data as: [2val-(max(val)-min(val)]/[max(val)+min(val)]
          except along dimensions [NOTnormdims] (':' list of dimension names, or 'any' for using all dimensions)
        'norm_meanstd',[NOTnormdims]: normalization of data as: (val-)/stdev(val) except along
          dimensions [NOTnormdims] (':' list of dimension names, or 'any' for using all dimensions)
           dimensions [NOTnormdims] (':' list of dimension names)
        'pot': powering with [var] ([prevalues] ** [var])
        'potc',[modval1]: [prevalues] ** [modval1]
        'repl',[modval1]: replace values of [prevalues] with values from [operfile2var] except
          values in second file = [modval1]
        'replbig',[modval1]: replace values of [prevalues] with values from [operfile2var] except
          values in second file > [modval1]
        'repless',[modval1]: replace values of [prevalues] with values from [operfile2var] except
          values in second file < [modval1]
        'sub': substracting [var] ([prevalues] - [var])
        'subc',[modval1]: remove [modval1] of [prevalues]
        'upthres',[modval1],[modval2]: if [prevalues] > [modval1]; prevalues = [modval2]
        'upthres@oper',[modval1],[oper],[modval2]: if [prevalues] > [modval1]; prevalues = [oper] (operation with [modval2])
      * [file]: name of the file
      * [var]: variable to use ('None' for the case with constant operations: 'addc', 'divc', 'inv', 'lowthres',
        'lowthres@oper', 'mulc', 'potc', 'subc', 'upthres', 'upthres@oper'
  varinfo= [varname],[Lvarname],[varunits]
    varname: name of the final variable
    Lvarname: long name of the final variable ('!' for spaces)
    varunits: units of the final variable ('!' for spaces)