That one related to the ORIGIN is the minor problem. I take it as it is. Instead, the biggest problem that I still not solved is related to the OUTPUT : iteration vs partial solution of the system. I cannot make the function/file to group all iteration solutions in a table or a matrix. The file is attached in the previous messaje.
The solution, just for the given example from the file should appear like this (in table or matrix format):
I cannot obtain this entire table of partial solutions, I can obtain displayed only the final solutions (1 , -3, 4, 0.5) from the last iteration 15 when it is matched the convergence. For me it is not enough, and I am frustrated to be locked only in a problem of displaying the solution despite the algorithm from there solved the problem.
Finally I obtained the OUTPUT in the way represented in the attached file. If anybody have an additional idea to compact more the algorithm, I am waiting with interest. I attached the file.
Thank you very much for the support. You are cool.
I see you found it.
You have to note: The result of a function is the result of the last statement executed in the function. Generally it is better (programming practice) to use the explicit statement involving 'return' for that. (Note that you cannot type 'return', you have to take it from the programming palet.)
But 'return' can also be used in the middle of a program. basically it causes the program to stop and present the result of its argument.
Here's a very simple example:
Now see what happens if I take away the last statement:
If you end a program with a loop (a for loop in this case) the last statement of the last iteration through the loop is returned as the result. Hope this helps with understanding Mathcad progams.
Success!
Luc
Still exist a problem: while the partial solutions are extracted correctly for displaying, instead the partial errors are extracted bad. I don't know why.
Please, see on the attached file.
I found. There was problem in link with how xold read the values of x from the previous cycle of while. So I added a new FOR instruction for reading.
Thank you very much. Now the problem solved exhaustively. I attached the corrected file to be used by others interested.
If you want 'more elegance' and more general usability, you should make your program work independently from the actual value of ORIGIN. For that you have to use the variable ORIGIN in your program, but at the right place.
Here's an example, simple, but it's for demonstration purposes:
The functions vectorsum() and sumvector() both attempt to sum alle elements of the vector supplied in the argument. The answer, 1+2+3=6, is easy.
Since ORIGIN=0 ate the start, vectorsum() fails, because it incorrectly assumes the ORIGIN=1.
Just setting ORIGIN to 1 after the definition of the function doesn't help. The function must be redefined before vectorsum() runs with no error.
As you can see sumvector() is well programmed, it works irrespective of the actual value of ORIGIN.
Note that length() give the length of a vector, in itself that number is '1-based' (starts at 1) so it generally works with an ORIGIN setting of 1.
In general, using ORIGIN and last() cause the least problems when indexing vectors. For matrices the functions rows() and cols() behave similar to length() of a vector. They give the number of rows and columns. So with matrices you'd have to define lastrow() and lastcol() yourself, or work with ORIGIN+rows()-1, and ORIGIN+cols()-1 respectively. Note that while ORIGIN is usually set to either 0 or 1, it can be set to (almost) any number. You could set it to -10, or 100...
Success!
Luc
