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<TITLE>PetscRandomCreate</TITLE>
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<A NAME="PetscRandomCreate"><H1>PetscRandomCreate</H1></A>
Creates a context for generating random numbers, and initializes the random-number generator.
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscsys.h"
int PetscRandomCreate(MPI_Comm comm,PetscRandomType type,PetscRandom *r)
</PRE>
Collective on MPI_Comm
<P>
<H3><FONT COLOR="#CC3333">Input Parameters</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B><A HREF="../Sys/comm.html#comm">comm</A> </B></TD><TD>- MPI communicator
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>type </B></TD><TD>- the type of random numbers to be generated, usually RANDOM_DEFAULT
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Output Parameter</FONT></H3>
<DT><B>r </B> -the random number generator context
<br>
<P>
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
By default, we generate random numbers via srand48()/drand48() that
are uniformly distributed over [0,1). The user can shift and stretch
this interval by calling <A HREF="../Sys/PetscRandomSetInterval.html#PetscRandomSetInterval">PetscRandomSetInterval</A>().
<P>
Currently three types of random numbers are supported. These types
are equivalent when working with real numbers.
<DT><B>RANDOM_DEFAULT </B> -both real and imaginary components are random
<br>
<DT><B>RANDOM_DEFAULT_REAL </B> -real component is random; imaginary component is 0
<br>
<DT><B>RANDOM_DEFAULT_IMAGINARY </B> -imaginary component is random; real component is 0
<br>
<P>
Use <A HREF="../Vec/VecSetRandom.html#VecSetRandom">VecSetRandom</A>() to set the elements of a vector to random numbers.
<P>
<H3><FONT COLOR="#CC3333">Example of Usage</FONT></H3>
<PRE>
<A HREF="../Sys/PetscRandomCreate.html#PetscRandomCreate">PetscRandomCreate</A>(PETSC_COMM_SELF,RANDOM_DEFAULT,&r);
<A HREF="../Sys/PetscRandomGetValue.html#PetscRandomGetValue">PetscRandomGetValue</A>(r,&value1);
<A HREF="../Sys/PetscRandomGetValue.html#PetscRandomGetValue">PetscRandomGetValue</A>(r,&value2);
<A HREF="../Sys/PetscRandomGetValue.html#PetscRandomGetValue">PetscRandomGetValue</A>(r,&value3);
<A HREF="../Sys/PetscRandomDestroy.html#PetscRandomDestroy">PetscRandomDestroy</A>(r);
</PRE>
<P>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../Sys/PetscRandomGetValue.html#PetscRandomGetValue">PetscRandomGetValue</A>(), <A HREF="../Sys/PetscRandomSetInterval.html#PetscRandomSetInterval">PetscRandomSetInterval</A>(), <A HREF="../Sys/PetscRandomDestroy.html#PetscRandomDestroy">PetscRandomDestroy</A>(), <A HREF="../Vec/VecSetRandom.html#VecSetRandom">VecSetRandom</A>()
<BR><P><B><P><B><FONT COLOR="#CC3333">Level:</FONT></B>intermediate
<BR><FONT COLOR="#CC3333">Location:</FONT></B><A HREF="../../../src/sys/src/utils/random.c.html#PetscRandomCreate">src/sys/src/utils/random.c</A>
<BR><A HREF="./index.html">Index of all Sys routines</A>
<BR><A HREF="../../index.html">Table of Contents for all manual pages</A>
<BR><A HREF="../singleindex.html">Index of all manual pages</A>
<P><H3><FONT COLOR="#CC3333">Examples</FONT></H3>
<A HREF="../../../src/sles/examples/tutorials/ex2.c.html">src/sles/examples/tutorials/ex2.c.html</A><BR>
<A HREF="../../../src/sles/examples/tutorials/ex4.c.html">src/sles/examples/tutorials/ex4.c.html</A><BR>
<A HREF="../../../src/sles/examples/tutorials/ex11.c.html">src/sles/examples/tutorials/ex11.c.html</A><BR>
<A HREF="../../../src/sles/examples/tutorials/ex2f.F.html">src/sles/examples/tutorials/ex2f.F.html</A><BR>
<A HREF="../../../src/sles/examples/tutorials/ex11f.F.html">src/sles/examples/tutorials/ex11f.F.html</A><BR>
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