sub rebinner_interp{
#Rebinning portion of analysis code.  Define local variables used in this subroutine
    my $idx, my $buf, my $i, my $j, my @calibcoeff;
    my @energy_rebin, my @values, my @energy_before;
    my $chn;
    my @acoeff, my @bcoeff, my @ccoeff;
#Note: $spec, %slope[] and %intercept[] are global variables that have been defined earlier

#User to input their bin-width of choice, define new energy binning structure that is universal for all spectra 
    printf STDOUT "Please enter the energy width (in keV) of each bin\n";
    chomp (my $rebin_width = <STDIN>);
    for ($i=0; $i<16834; $i++){
	$energy_rebin[$i] = ($rebin_width * $i);
    }

#For each spectrum, $idx, read in original spectrum in VAX format to array @rawchannel
    for ($idx=0; $idx<=$spec; $idx++){
	my @rawchannel;
	open (INFILE, "<", "filename.spc") 
	    or die "Can't find spectrum: filename.spc";
	while (read(INFILE, $buf, 4) == 4) {
	    if (length($buf) > 0 && length ($buf) < 4){
		next;
	    }
	    else{
		push @rawchannel, scalar unpack('V',$buf);
	    }
	}
	close INFILE;

#For $idx, determine the energy binning before from pre-determined calibration
	$chn = 0;
	$i = 1;
	for ($chn=0;$chn<16384;$chn++){
	    if ($i == $calib_points){
		$energy_before[$chn] = ($slope{$idx}[$i]*${chn})+$intercept{$idx}[$i];
	    }
	    if (($chn<=$channel{$idx}[$i])&&($i<$calib_points)){
		$energy_before[$chn] = ($slope{$idx}[$i]*$chn)+$intercept{$idx}[$i];
	    }
	    elsif (($chn > $channel{$idx}[$i]) && ($i < $calib_points)){
		$i += 1;  
		$energy_before[$chn] = ($slope{$idx}[$i]*$chn)+$intercept{$idx}[$i];  
	    }
	    
	}
#Originally, test script placed here to check the output of each @energy_rebin and @energy_before.  So the script should be fine up to here.

#Define @counts_rebin for each spectrum which will contain the number of counts per channel for each rebinned spectrum 
	$j=0;
	my $k = 0;
	my @counts_rebin;
	my $value;
#Loops to generate rebinned spectrum.  First part intended to define a value for $counts_rebin[$j] if undefined.  Then depending on the order add all or part of the bin as fit.  Note, from test $k is always less than 16382.
	for($j=0; $j<=16831; $j++){
	    if(($energy_rebin[$k] >= $energy_before[$j])){ # l:1148
		if ((defined($counts_rebin[$k]))==0){
		    $counts_rebin[$k]=0;
		}
		$value = $rawchannel[$j];
		$counts_rebin[$k] = ($counts_rebin[$k] + $value); # l:1153
		next;
	    }
	    if(($energy_rebin[$k] < $energy_before[$j]) && $j!=0){
		my $totcount = $rawchannel[$j];
		my $split1 = (($energy_before[$j]-$energy_rebin[$k])*$totcount)/($energy_before[$j]-$energy_before[${j}-1]); # l:1158
		if ((defined($counts_rebin[$k]))==0){
		    $counts_rebin[$k]=0;
		}
		$counts_rebin[$k]=($counts_rebin[$k]+($totcount-$split1)); # l:1162
		$counts_rebin[$k+1]=$split1;
		$k+=1;
		next;
	    }
	    if(($energy_rebin[$k]<$energy_before[$j]) && $j==0){
		until ($energy_rebin[$k]>=$energy_before[$j]){
		    $k += 1;
		}
		$value = $rawchannel[$j];
		$counts_rebin[$k] = $counts_rebin[$k] + $value;
		next;
	    }
	}
#As $counts_rebin[$j] only partially filled, define the rest of the array (up to 16382) as undefined 
	$j=0;
	for ($j=0;$j<=16381;$j++){
	    if (defined($counts_rebin[$j])){
		next;
	    }
	    else{
		$counts_rebin[$j]=0;
	    }
	}

#Output the file in a little-endian VAX format
	open (REBINOUT, ">", "filename.spr");
	binmode REBINOUT, ":raw";
	for ($i=0;$i<=16831;$i++){
	    printf REBINOUT pack('V',$counts_rebin[$i]); # l: 1188
	}
	close REBINOUT;
    }
}