# Reverse algorithm

The reverse algorithm allows to key in a number on a calculated data
block and save a value, derived through a reverse formula to a specified
InfoCube.

## Example

Consider the following data-entry report:

The data block (a) contains the Budget
Quantity InfoCube and data entry has been enabled on this block.
The user can enter a budget value on this block.

The second column, Last
Year Actual Sales contains the sales value of last year, it is
a reference value that helps the user defining the budget.

The third column, block (c), is the variance in percentage obtained
with a column algorithm with the formula c=(a-b)/b*100.
Data entry is enabled on this data block, allowing the user to key-in
a percentage of variance and letting the system to derive the Budget Quantity
corresponding to the given variance. The Budget quantity value is derived
by applying the reverse formula a=b*(c+100)/100,
this is the Reverse Algorithm.

In the reverse
algorithm field, type the formula starting with the data block that is
the variable to change when the user keys-in a value, followed by the
equal sign and the formula itself as in the following example.

Note:

The target data block of the reverse algorithm must
be an InfoCube and must have the data entry option enabled.