David Bateman wrote:
MartinHepperle wrote:
Hello all,
again this nasty Java -> Octave connection.
I also want to embed Octave into a Java program and call Octave
functions
from Java.
Initially I started with programming an execution engine which starts
octave.exe and connected to its standard input and output pipes. This
concept works (in the meantime I also found two solutions which
implement
the same technique) but is somewhat ugly and inefficient due to
conversions
to and from strings
What I tried now was to call the Octave DLLs (Windows platform)
directly via
a C wrapper and using JNI.
This technique provides a very elegant solution and I have used this
in the
past to call C and FORTRAN codes from Java. I want to define some global
variables, set the values from Java, execute some user supplied
functions
and finally return the results (global variables set inside the user
functions) to Java.
Now with the Octrave DLLs I stumbled across a problem.
To study the interface to ther DLLs I started with a C++ program.
Basically I used the following logic:
//-----------------------------
// start and initialize Octave (once, then keep it alive)
char * pArgs[] = {"octave.exe","--path", "C:\\Programme\\Octave",
"--norc",
NULL};
int iRet = octave_main (4 pArgs, true);
//-----------------------------
// execute some commands
std::string s = std::string("global Output;\nglobal
Input;\nInput=12;\nOutput=2*Input;\n");
octave_value x = eval_string (s, false, parse_status);
// examine the returned "x" with x.isnumeric() etc. works when code
is in an
executable (.exe) file
// what does the follwing code do? It works, but where is the
variable in
Octave?
set_global_value (std::string(cName), val);
octave_value vReturn = get_global_value (std::string(cName));
// the variable has the correct value, but is_globally_visible
(std::string(Name)) returns false...
// what does global mean here?
// terminate Octave
do_octave_atexit();
//-----------------------------
All this works well when I have the code inside an executable C++
program
(MSVC8.0).
So far so good.
Now for the interface via JNI I have to put this into a DLL which
provides a
thin layer between Java objects and the C interface to Octave.
If I put the same code inside a DLL I can initialize Octave, but the
eval_string () and other functions doe not work - they seem to do
nothing. I found can do somethings with set_global_value () and
get_global_value (),
but this is not enough and also these "global" values seem to be
something
else than global variables in Octave.
Anyway, I see that eval_string() seems to work when called from a C
executable, but not when I call it from a DLL. Could this have
something to
do with i/o streams which are different in a DLL and in an EXE?
Any ideas where to look and how to test?
Thank You,
Martin
eval_string can only work if the interpreter is initialized.. Check
the mailing lists for how to initialize the interpreter.
D.
Seeing as how this question has come up a number of times, I suggest the
attached changeset that adds an example of how to initialize the
interpreter and use it from a standalone application.
Regards
David
--
David Bateman [EMAIL PROTECTED]
Motorola Labs - Paris +33 1 69 35 48 04 (Ph)
Parc Les Algorithmes, Commune de St Aubin +33 6 72 01 06 33 (Mob)
91193 Gif-Sur-Yvette FRANCE +33 1 69 35 77 01 (Fax)
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[ ] Motorola Confidential Proprietary
# HG changeset patch
# User David Bateman <[EMAIL PROTECTED]>
# Date 1220603756 -7200
# Node ID 2ea73884a0043cee526dc0651bdee03f217e7f30
# Parent 686fedc6a026f0aaafbfe95c53a362060af94d7f
Add explanationation of initializing the interpreter in a standalone program
diff --git a/doc/interpreter/dynamic.txi b/doc/interpreter/dynamic.txi
--- a/doc/interpreter/dynamic.txi
+++ b/doc/interpreter/dynamic.txi
@@ -1621,28 +1621,7 @@ following C++ program, uses class Matrix
following C++ program, uses class Matrix from liboctave.a or
liboctave.so.
[EMAIL PROTECTED]
[EMAIL PROTECTED]
-#include <iostream>
-#include <octave/oct.h>
-int
-main (void)
[EMAIL PROTECTED]
- std::cout << "Hello Octave world!\n";
- int n = 2;
- Matrix a_matrix = Matrix (n, n);
- for (octave_idx_type i = 0; i < n; i++)
- @{
- for (octave_idx_type j = 0; j < n; j++)
- @{
- a_matrix (i, j) = (i + 1) * 10 + (j + 1);
- @}
- @}
- std::cout << a_matrix;
- return 0;
[EMAIL PROTECTED]
[EMAIL PROTECTED] group
[EMAIL PROTECTED] example
[EMAIL PROTECTED]
@noindent
mkoctfile can then be used to build a standalone application with a
@@ -1650,8 +1629,8 @@ command like
@example
@group
-$ mkoctfile --link-stand-alone hello.cc -o hello
-$ ./hello
+$ mkoctfile --link-stand-alone standalone.cc -o standalone
+$ ./standalone
Hello Octave world!
11 12
21 22
@@ -1660,4 +1639,24 @@ Hello Octave world!
@end example
Note that the application @code{hello} will be dynamically linked
-against the octave libraries and any octave support libraries.
+against the octave libraries and any octave support libraries. The above
+allows the Octave math libraries to be used by an application. It does
+not however allow the script files, oct-files or builtin functions of
+Octave to be used by the application. To do that the Octave interpreter
+needs to be initialized first. An example of how to do this can then be
+seen in the code
+
[EMAIL PROTECTED]
+
[EMAIL PROTECTED]
+which is compiled and run as before as a standalone application with
+
[EMAIL PROTECTED]
[EMAIL PROTECTED]
+$ mkoctfile --link-stand-alone embedded.cc -o embedded
+$ ./embedded
+GCD of [10, 15] is 5
+$
[EMAIL PROTECTED] group
[EMAIL PROTECTED] example
+
diff --git a/examples/Makefile.in b/examples/Makefile.in
--- a/examples/Makefile.in
+++ b/examples/Makefile.in
@@ -39,6 +39,7 @@ SOURCES = \
SOURCES = \
addtwomatrices.cc \
celldemo.cc \
+ embedded.cc \
firstmexdemo.c \
fortdemo.cc \
fortsub.f \
@@ -62,6 +63,7 @@ SOURCES = \
oregonator.cc \
oregonator.m \
paramdemo.cc \
+ standalone.cc \
stringdemo.cc \
structdemo.cc \
unwinddemo.cc
diff --git a/examples/embedded.cc b/examples/embedded.cc
new file mode 100644
--- /dev/null
+++ b/examples/embedded.cc
@@ -0,0 +1,43 @@
+#include <iostream>
+#include <octave/oct.h>
+#include <octave/octave.h>
+#include <octave/parse.h>
+int
+main (void)
+{
+ string_vector argv (2);
+ argv(0) = "embedded";
+ argv(1) = "-q";
+
+ octave_main (2, argv.c_str_vec(), 1);
+
+ octave_idx_type n = 2;
+ Matrix a_matrix = Matrix (1, 2);
+
+ std::cout << "GCD of [";
+ for (octave_idx_type i = 0; i < n; i++)
+ {
+ a_matrix (i) = 5 * (i + 1);
+ if (i != 0)
+ std::cout << ", " << 5 * (i + 2);
+ else
+ std::cout << 5 * (i + 2);
+ }
+ std::cout << "] is ";
+
+ octave_value_list in = octave_value (a_matrix);
+ octave_value_list out = feval ("gcd", in, 1);
+
+ if (!error_state && out.length () > 0)
+ {
+ a_matrix = out(0).matrix_value ();
+ if (a_matrix.numel () == 1)
+ std::cout << a_matrix(0) << "\n";
+ else
+ std::cout << "invalid\n";
+ }
+ else
+ std::cout << "invalid\n";
+
+ return 0;
+}
diff --git a/examples/standalone.cc b/examples/standalone.cc
new file mode 100644
--- /dev/null
+++ b/examples/standalone.cc
@@ -0,0 +1,18 @@
+#include <iostream>
+#include <octave/oct.h>
+int
+main (void)
+{
+ std::cout << "Hello Octave world!\n";
+ int n = 2;
+ Matrix a_matrix = Matrix (n, n);
+ for (octave_idx_type i = 0; i < n; i++)
+ {
+ for (octave_idx_type j = 0; j < n; j++)
+ {
+ a_matrix (i, j) = (i + 1) * 10 + (j + 1);
+ }
+ }
+ std::cout << a_matrix;
+ return 0;
+}
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