ED HAYES

I ran into a problem the other day trying to fix a printed Commercial Invoice calculation we are doing in BI Publisher. Turns out the issue was that the Format Number and Format Currency functions use a different rounding algorithm than the Round function! Here is the story of how I came to find this out.

We have some prices that are in 10ths of a cent; three decimal of precision on currency. When we add up a line total on a Commercial Invoice, we format the answer using the format-currency function.  At each line we also add to a running total variable which is displayed at the end of the document.  When we add to the running total, we have to make sure not to add the 3rd decimal, as that would likely cause a rounding error in the total verse what is showed on the lines.

Here are all the function definitions for the applicable functions we are using:

Format Currency
<?format-currency:ELEMENT_NAME;’currency-format-code’;’display-symbol’?>

Format Number
<?format-number:ELEMENT_NAME;’format-mask’?>

Round
<?xdoxslt:round(number(./ELEMENT_NAME),decimal_precision)?>

Set Variable
<?xdoxslt:set_variable($_XDOCTX, ‘VARIABLE_NAME’, VARIABLE_VALUE)?>

Get Variable
<?xdoxslt:get_variable($_XDOCTX, ‘VARIABLE_NAME’)?>

How we are using the functions:

Set Variable for line total:
<?xdoxslt:set_variable($_XDOCTX, ‘v_line_total’, xdoxslt:get_variable($_XDOCTX, ‘v_quantity’) *ORDER_LINE_PRICE )?>

Display line total
<?format-currency:xdoxslt:get_variable($_XDOCTX, ‘v_line_total’);ORDER_LINE_PRICE_CURRENCY_CODE;’true’?>

Add to running sum
<?xdoxslt:set_variable($_XDOCTX, ‘v_total’,xdoxslt:get_variable($_XDOCTX,’v_total’)+xdoxslt:round(xdoxslt :get_variable($_XDOCTX,’v_line_total’),2))?>

Display running total
<?format-currency:xdoxslt:get_variable($_XDOCTX, ‘v_total’)   ;../../LIST_CUSTOMER_ORDER/CUSTOMER_ORDER/CURRENCY_CODE;’true’?>

For reference and testing; not actually used on the document
<?format-number:ELEMENT_NAME;’999G999D99′?>

The problem we are having is that the line totals are not adding up to the running total.

I did some tests and apparently the format based functions round using the “round-to-even” method, and the standard round function rounds using what you would expect, and learned in elementary school.

Appears as though I’m going to have to round the line total before I use the currency formatting function.

What an irritating situation.  It took a few hours to figure this out; huge waste of my time.  It would have been nice if they put the option of how to round as a parameter in the function, or documented this nonsense.