[GRASS-user] use pi number

[José María Michia]

Hello. I can not use the number pi in r.mapcalc. I tried these ways:

r.mapcalc 'prueba = pi()'
r.mapcalc 'prueba = pi'
r.mapcalc 'prueba = PI()'
r.mapcalc 'prueba = PI'

With the following results:

Syntax error

Is this normal? Is IP defined within GRASS / r.mapcalc?

Thanks for your help.
José María