I'm trying to run the example 'xrk4.c' with a great deal of difficulty. I have included nr.h and nrutil.h along with source files nutil.c and rk4.c and the code will not compile. The errors are linking errors:

Undefined symbol '_bessj" referenced in "xrk4.c"
Undefined symbol '_bessj0" referenced in "xrk4.c"
Undefined symbol '_bessj1" referenced in "xrk4.c"

I've attempted to run this code in three different compilers with no success - so it must be something that I'm doing.

Any suggestions are appreciated.

ALI

Dear Ali,

The example uses Bessel functions. You need to also compile and link bessj0.c, bessj1.c and bessj.c.

Saul Teukolsky

Thank you very much for pointing that out Mr. Teukolsky. It was a silly mistake on my part.

I have since added the appropriate bessj recipes to the code. The error I'm getting now involves nrutil.c whereby the message I keep getting each time I run the code is:

NON-FATAL RUN-TIME ERROR: "nrutil.c", line 25, col 12, thread id 0x000000C0: Out-of-bounds pointer arithmetic: 4 bytes (1 elements) before start of array.

I'm I doing something wrong or do I need to fiddle with the settings of my compiler?

Thanks again,

ALI

Dear Ali,

This should not cause a problem. If you are curious about why your compiler is complaining (most don't), read the section on unit-offset vectors in Appendix B. If you have a compiler option that let's you turn off checking the pointer arithmetic, you could try that.

Saul Teukolsky