5.3.8 timer

Type:

int

Purpose:

1. the CPU time (i.e, user and system time) used for each command is printed if timer >0 , if this time is bigger than a (customizable) minimal time and if printlevel+1 >= voice (which is by default true on the SINGULAR top level, but not true while procedures are executed).

2. yields the CPU time used since the start-up of SINGULAR in a (customizable) resolution.

The default setting of timer is 0, the default minimal time is 0.5 seconds, and the default timer resolution is 1 (i.e., the default unit of time is one second). The minimal time and timer resolution can be set using the command line options --min-time and --ticks-per-sec and can be checked using system("--min-time") and system("--ticks-per-sec").

How to use timer in order to measure the time for a sequence of commands, see example below.

Note for Windows95/98:

The value of the timer cannot be used (resp. trusted) when SINGULAR is run under Windows95/98 (this is due to the shortcomings of the Windows95/98 operating system). Use rtimer, instead.

Example:

timer=1; // The time of each command is printed int t=timer; // initialize t by timer ring r=0,(x,y,z),dp; poly p=(x+2y+3z+4xy+5xz+6yz)^20; // timer as int_expression: t=timer-t; t; // yields the time in ticks-per-sec (default 1) ==> 0 // since t was initialized by timer int tps=system("--ticks-per-sec"); t div tps; // yields the time in seconds truncated to int ==> 0 timer=0; system("--ticks-per-sec",1000); // set timer resolution to ms t=timer; // initialize t by timer p=(x+2y+3z+4xy+5xz+6yz)^20; timer-t; // time in ms ==> 30