Why Does My Matrix Vector Multiplication in FORTRAN Not Work as Expected?

[Milentije]

I have a problem with something that should be very simple,I do not no if it is programming issue or my ignorance.
If I have matrix c(5,5)
3 0 0 0 0
1 2 0 0 0
0 1 2 0 0
0 0 1 4 1
0 0 0 1 2
and vector b(1,2,3,4,5)

c*b=a

a=(3,5,8,24,14)
FORTRAN MATMUL
C=MATMUL(B,A)

Correct?

 

[CompuChip]

a=(3,5,8,24,14)

That is correct.

C=MATMUL(B,A)
I don't know Fortran at all, but here you are multiplying B and A to get C. This is different from what you said earlier (multiplying C and B to get A). I don't know that MATMUL does with two vectors, but you will either get a number (the inner product) or a matrix (but not the one you expect).

Did you mix up your naming, or ... ?

 

[SteamKing]

Here is information on the intrinsic function MATMUL:

http://h21007.www2.hp.com/portal/download/files/unprot/fortran/docs/lrm/lrm0285.htm

BTW, if you have knowledge, you 'know' something. 'no' means negation or the absence of something.

 

[HallsofIvy]

I do not no if it is programming issue or my ignorance

'no' means negation or the absence of something.

Perhaps here he used it correctly!