[lilas]

Hello All!!

I am trying to interpret the following udf for a cylindrical heat source

#include <udf.h>

DEFINE_SOURCE(laser,cell,thread,dS,eqn)
{

real current_time=CURRENT_TIME;
real PI=acos(-1);

//parameters
real d=1e-4; // 100 micron
real P=195.0; //Power

//start pos
real xs= 5.0;
real ys=5.0;


real source;
real eta=0.5;

// cell paramters
real x[ND_ND];


C_CENTROID(x,cell,thread);
real x1=x[0];
real y1=x[0];


source= eta*2*P/(PI*d*d) * exp(-2*(pow(x1-xs,2)+pow(y1-ys,2))/pow(d,2));


dS[eqn]=0;
return source;

}

It says

line 26: parse error.
line 27: parse error.
line 30: x1: undeclared variable

The error doesn't occur when I comment the C_CENTROID line. What am I doing wrong? I have previously used C_CENTROID for initialization without any issues

[PKP_India]

hi,

you can try a cell-thread loop as below to access the centroid coordinates.

real x1;
real y1;
begin_c_loop(cell,thread)
{
C_CENTROID(x,cell,thread);
x1=x[0];
y1=x[1];
}
end_c_loop(cell,thread)

I hope it will help.

[lilas]

Thanks for the reply, I figured out that the error was that one cannot declare a variable after an assignment has been made in these versions of C. Probably the C_CENTROID macros has an implicit assignment operation somewhere