array element (matrix) question 
Author Message
 array element (matrix) question

HI,
I have a question about how to simulaneously compare two matrices. Ex
A(2,3)=[1 1 2]
           [ 2 1 0]
B(2,3)=[3 0 3]
           [2 1 2]

HOw to make a statement to compare all the elements of A and B?
If (All elements of A  <= all elements of B) then
....
else ....

I know there is a transformational Intrinsic Function called "all",
also there is
where
elsewhere
end where

but I just know that All (matrix), the matrix should be logical array.
what can I do?
and the "where " above only considers element-by-element, not all
element of the matrix.
Also can anyone suggest some good readings or books about F90/95 and
mention more about the matrices or array calculation?
I have a book of fortran 90/95 for scientists and Engineers by Stephen
J Chapman.
But it seems not enough for me.
Thank you very much.



Tue, 28 Oct 2008 05:25:21 GMT  
 array element (matrix) question

Quote:

> HOw to make a statement to compare all the elements of A and B?
> If (All elements of A  <= all elements of B) then
...
> I know there is a transformational Intrinsic Function called "all",

Yes, you are on the right track there.

Quote:
> but I just know that All (matrix), the matrix should be logical array.
> what can I do?

Many operations on arrays are elemental, that is they operate on each
element of the array and give an array result. This includes the
relational operations like "<=". Thus A<=B gives a logical array, each
element of which compares the corersponding element of A and B. So what
you want is

  if (all(A<=B)) then
    ...

Quote:
> I have a book of Fortran 90/95 for scientists and Engineers by Stephen
> J Chapman.

Not my favorite book. :-( But I'm not sure a book will quite give the
right kind of insights to help much with writing array expressions like
this. Anyway, if there is a book that helps much with that, I don't know
of it. I think it helps more to ask a few questions like this and see
the ways that people use the array intrinsics and operations. After
seeing a few examples like that, you might be better able to pick it up.
Though maybe someone else has better ideas on how to teach such things
than I do.

--
Richard Maine                     | Good judgment comes from experience;
email: my first.last at org.domain| experience comes from bad judgment.
org: nasa, domain: gov            |       -- Mark Twain



Tue, 28 Oct 2008 05:40:58 GMT  
 array element (matrix) question
Hi Richard,
It works! I am looking for some useful books of fortran programming.
Would you please recommend some books for me? Thank you very much.


Tue, 28 Oct 2008 06:26:50 GMT  
 array element (matrix) question

Quote:

> It works! I am looking for some useful books of fortran programming.
> Would you please recommend some books for me? Thank you very much.

I'm personally fond of Metcalf&Reid, particularly as a first book. It is
relatively short and concise, which helps get you going, and I think it
has a clear writing style. There are arguments for supplementing it with
something more comprehensive, but I think it is at least one of the
books that should be on a Fortran programmer's shelf.

--
Richard Maine                     | Good judgment comes from experience;
email: my first.last at org.domain| experience comes from bad judgment.
org: nasa, domain: gov            |       -- Mark Twain



Tue, 28 Oct 2008 06:49:22 GMT  
 array element (matrix) question


Quote:

>> It works! I am looking for some useful books of fortran programming.
>> Would you please recommend some books for me? Thank you very much.

>I'm personally fond of Metcalf&Reid, particularly as a first book.

Me too. I also use and recommend the Fortran 95 Handbook by Adams,
Brainerd, Martin, Smith and Wagener, but when I hit real trouble there
is no substitute for c.l.f and the f95 or f2003 standard. Two or three
times contributors to c.l.f have corrected views that I had formed
after reading a misleading part of M&R or the Handbook. (In each case
I told the authors, and they included the matter among things to fix
in the next edition.) I still use M&R and the Handbook because they are
almost always right, and much easier to read than the standards. And
several c.l.f contributors do a great job of explaining obscure parts
of the standards.

-- John Harper, School of Mathematics, Statistics and Computer Science,
Victoria University, PO Box 600, Wellington, New Zealand



Tue, 28 Oct 2008 09:52:14 GMT  
 array element (matrix) question
Richard E Maine schrieb:

Quote:

>> It works! I am looking for some useful books of fortran programming.
>> Would you please recommend some books for me? Thank you very much.

> I'm personally fond of Metcalf&Reid, particularly as a first book. It is
> relatively short and concise, which helps get you going, and I think it
> has a clear writing style. There are arguments for supplementing it with
> something more comprehensive, but I think it is at least one of the
> books that should be on a Fortran programmer's shelf.

I recommend "FORTRAN 90/95 for Scientists and Engineers", Stephen J.
Chapman, McGraw Hill Higher Education (August 2003).

IMO it is well structured and suitable for learning and reference. But
FORTRAN 90/95 for Scientists and Engineers" is a textbook primarily.
Chapman offers complete little sample programs and procedures and not
only code snippets. IMHO this issue is very important for beginners
because you can see the mentioned statements in a code context. The
sample programs are very practical for people mentioned in the title and
easy to understand. You will even find tricks and hints for your
programming practice.

Additionally you will find text boxes for good programming practice,
Fortran 95-only statements and a abstract with training exercises after
each chapter. The appendix contains the solutions and other useful tables.

I also own "Fortran 95/2003 explained" from Metcalf&Reid. This book
describe the language briefly. IMO it is a good reference and less
suitable for learning. Here you will find the Fortran 2003 extensions also.

Best regards,

Hani



Tue, 28 Oct 2008 22:00:56 GMT  
 
 [ 6 post ] 

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