 Pascal triangle to a matrix - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: HP Prime (/forum-5.html) +--- 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:=[];   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