Help System (web edition)

Working with large data sets

In normal usage Survo is fairly verbose by telling on the screen
various details about current events when commands and operations
are activated. By default it also saves results of many operations
as text in a special output file (text file) given by 'eout'
in SURVO.APU (default is <Survo>\TMP\RESULTS).
When working with large data sets (especially in simulation experiments)
these subsidiary effects may be very time-consuming. Then, to spare time,
certain special settings are recommended.

Saving results to a text file is disabled by the command
OUTPUT -   (See OUTPUT?).

Unessential display of intermediate results in many operations is removed
by using a specification PRIND=0 and/or setting prind=0 in SURVO.APU.

In certain operations RESULTS=0 also eliminates unnecessary output.

See an example on the next page!

.......................................................................
Example: Correlations with different output options
Creating a sample of 10000 observations
from a 200-dimensional multivariate normal distribution:
p=200 r=0.7
MAT R=IDN(p,p,1-r)+CON(p,p,r)
MNSIMUL R,*,TEST,10000,0
.......................................................................
TIME COUNT START        / Calculations on a 366 MHz Pentium
CORR TEST / PRIND=1     / In all cases results saved in CORR.M and MSN.M
TIME COUNT END   39.870 / Temporary display of correlations took 20 sec.
.......................................................................
OUTPUT -  / Activate this before CORR!
TIME COUNT START
CORR TEST / PRIND=1
TIME COUNT END   10.270 / Listing of case numbers took almost 4 sec.
.......................................................................
OUTPUT -  / Activate this before CORR!
TIME COUNT START
CORR TEST / PRIND=0
TIME COUNT END   6.370  / Time when unessential displays are removed