The EXPORT: command is used to output certain quantities to files. It is possible to output data, the names of elements together with their expectations, covariance matrices, and correlation matrices. Various switches (d,n,e,t,r,v) are used to select the type of export. We deal with each of these separately below. There are some features common to each type of export. Firstly, any numbers exported are output with a number of decimal places set by the dplaces control. Secondly, all items exported are output via one of the output channels. Thus, prior to output, two steps must be followed before anything can be exported:
As an example, suppose that we wish to export items to an external file called exported in the current directory, and suppose also that we use output channel 3 for this purpose. Then we could issue the following commands:
We treat the channel for exported quantities pretty much as we treat ordinary output channels. Thus, exported quantities are typically appended to whatever has been written already by the program to the output channel. In this way we can generate on an external file a sequence of exported quantities from successive EXPORT: commands. For this reason, it is possible to define a label which will be exported as the first line of output.
