1. Language Issues Misunderstimated? Sublimable? Hopefuller?
"I know how hard it is for you to put food on your family.”
"I know the human being and fish can coexist peacefully."

2. Outline
Announcements:
HW1 due Friday
Developing RAD1D
Lab

3. Designing RAD1 Get C0, u, k, dt,t, T, m, L (dx=L/(m-1)) from user
Build matrix A using k, dt, dx
Build RHS vector f using u, k, and reaction data
Solve A*C=b for C
t=t+dt
If(t<T)
Copy C=C0
Change u and k if needed
Repeat 2-6
Else
d) Output C and quit

4. Getting Info From User Need several parameter values & a file name
Options:
Query user?
Values in a file & pass file name?
Cbasic basic.cmnd
I like option 3

5. Command File m--number of grid points L--length of the domain
dt--time step
T--end time

6. Designing Cbasics Get name of command file (user or command line)
Read command file and get m, L, dt, T
Create a length m array C
Fill array with location of grid points
Save C to C.txt

7. Structure of Cbasics Main.c--main program
Io.c--functions for input/output
ReadComm
ReportParams
PrintArray
System.c--functions for array allocation & error reporting
Error
newarray_double

8. Prototypes & Header files
C subroutines must declare the types of their inputs and outputs using “prototypes”
double sin(double angle_in_radians);
void PrintArray(char name[], double C[], int m);
Prototypes allow the compiler to check that you are calling a routine in the correct way
Suppose subroutine X is implemented in file X.c. In order to call X from another file (Y.c), Y needs to see the prototype for X.
Solution--create a header file with the prototype
X.c--implements X
X.h--prototype for X
Both X.c and Y.c must include X.h:
#include “X.h” must appear before any call to X or its implementation