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+--- Thread: Pascal triangle to a matrix (/thread-14032.html)
Pascal triangle to a matrix - Tonig00 - 11-22-2019 08:45 AM
Hello
I need some help. I do not program often and when I do I have doubts.
I try to put the values of the Pascal triangle,
1 --- m1(1,1)
1 1 --- m1(2,1) m1(2,2)
1 2 1 --- m1(3,1), etc
1 3 3 1
……………..
to a matrix that I call "m1" up to "f" lines, in the following way:
EXPORT Tri_Pa(f)
BEGIN
LOCAL n,m;
LOCAL m1;
FOR n FROM 0 TO f DO
FOR m FROM 0 TO n DO
m1(n,m):=COMB(n,m);
END;
END;
END;
But the program stops in the line "m1(n,m):=…", and says: "Invalid input".
How should I define the matrix to avoid the error?
Thanks in advance for your help
Toni
RE: Pascal triangle to a matrix - toml_12953 - 11-22-2019 01:07 PM
(11-22-2019 08:45 AM)Tonig00 Wrote: Hello
I need some help. I do not program often and when I do I have doubts.
I try to put the values of the Pascal triangle,
1 --- m1(1,1)
1 1 --- m1(2,1) m1(2,2)
1 2 1 --- m1(3,1), etc
1 3 3 1
……………..
to a matrix that I call "m1" up to "f" lines, in the following way:
Thanks in advance for your help
Toni
What does COMB(0,0) even mean? I don't see it as being useful.
Try this:
Code:
EXPORT Tri_Pa(f)
BEGIN
LOCAL n,m;
LOCAL m1:=makemat(0,f,f);
FOR n FROM 1 TO f DO
FOR m FROM 1 TO n DO
m1(n,m):=COMB(n,m);
END;
END;
END;RE: Pascal triangle to a matrix - Didier Lachieze - 11-22-2019 03:57 PM
(11-22-2019 08:45 AM)Tonig00 Wrote: But the program stops in the line "m1(n,m):=…", and says: "Invalid input".
How should I define the matrix to avoid the error?
You get an error because:
- You need to define m1 as a matrix
- Matrix indices start at 1 and not 0
So here is a working version of your program :
Code:
EXPORT Tri_Pa(f)
BEGIN
LOCAL n,m;
LOCAL m1:=[[0]];
FOR n FROM 0 TO f-1 DO
FOR m FROM 0 TO n DO
m1(n+1,m+1):=COMB(n,m);
END;
END;
END;Note that you can also generate the same matrix using just the MAKEMAT function:
Code:
EXPORT Tri_Pa(f)
BEGIN
MAKEMAT(IFTE(I<J,0,COMB(I-1,J-1)),f,f);
END;RE: Pascal triangle to a matrix - Tonig00 - 11-22-2019 07:14 PM
Thanks very much
Both works, and very interesting how the matrix works and the IFTE function.
Thanks