### CSUB

Subtracts a scalar from an NDF data structure

#### Description:

The routine subtracts a scalar (i.e. constant) value from each pixel of an NDF’s  data array to produce a new NDF data structure.

#### Usage:

csub in scalar out

#### Parameters:

Input NDF data structure, from which the value is to be subtracted.
##### OUT = NDF (Write)
Output NDF data structure.
The value to be subtracted from the NDF’s data array.
The title for the output NDF. A null value will cause the title of the NDF supplied for Parameter IN to be used instead. [!]

#### Examples:

csub a 10 b
This subtracts ten from the NDF called a, to make the NDF called b. NDF b inherits its title from a.
csub title="HD123456" out=b in=a scalar=21.9
This subtracts 21.9 from the NDF called a, to make the NDF called b. NDF b has the title "HD123456".