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August 28, 2015   Compiled on May 23, 2020 at 8:57am

### 2 how to call Lapack and Blas directly from Ada

This page is obsolete now, left here for archive and information only.

#### 2.1 Introduction

And made some minor improvments to the bindings.

This page describes the minor changes made and instructions how to use these bindings from Ada in order call LAPACK and BLAS Fortran functions.

A new tar ﬁle for LAPACK and for BLAS with all the changes can be downloaded from the link below.

The changes made to LAPACK binding involve streamlining the source tree structure, writing new Makeﬁles, simplify the binding to use one package called lapack and also adding the documentation shown below.

Changes for the BLAS binding were minimal. It involved changes to the source tree structure and writing Makeﬁles and adding the documentation shown below.

#### 2.2 Review of the LAPACK and BLAS Ada binding

The Ada binding to LAPACK and BLAS is an Ada package which allows one to interface to the native lapack and blas libraries.

The native lapack and blas libraries need to be ﬁrst installed on the system (on Linux, these libraries will normally be found in /usr/lib/liblapack.so and /usr/lib/libblas.so )

To use LAPACK from Ada, one needs to install both the native LAPACK and BLAS libraries since LAPACK depends on BLAS.

The Ada binding is a thin binding, meaning there is 1-1 mapping between the call to the Ada routine and the corresponding Fortran routine using the same function name in the Fortran libraries.

The following diagram illustrates the use of the LAPACK binding with the needed gnatmake command to compile and link the client Ada program.

And a similar diagram for the BLAS binding interface

The source tree structure for LAPACK is described in this diagram

The full content of the LAPACK tree is listed here lapack_tree_listing.txt

The source tree structure for the BLAS binding is described in this diagram

#### 2.3 Installation instruction

These instructions explain how to use the Ada LAPACK and BLAS binding in the updated snapshot tar ﬁle.

1. install native lapack 77 and blas libraries on your system. These will normally be installed in /usr/lib/.
3. Extract the zip ﬁles to some location. This will create 2 source trees as shown in the diagrams above.
4. At the top of the each source tree, there is a ﬁle called common.mk where a Makeﬁle variable is set to point to the directory that contains the native LAPACK and BLAS libraries. This is currently deﬁned to point to /usr/lib. Edit this line to change this location only if the location is diﬀerent in your system.
5. To build the binding, just type make from the top of each tree. Make will build the whole tree, including the bindings packages and the test programs.
6. To run the test program, type make testing from the top of tree for LAPACK and for BLAS.
7. Examples of clients using the bindings are found in the tests/ directory of each tree.
8. The binding is in the binding/ directory in each tree. This is the directory that you need to set the -I option to point to when using gnatmake as shown in the diagrams above.
9. The following is a simple example of using the Ada LAPACK binding to solve $$Ax=b$$ mysolve.adb.txt which can also be found in the ada_lapack/tests/pilot/ directory
10. That is all! Have fun using Ada with LAPACK and BLAS.

### 3 How to compile GTK Ada program

$gnatmake -I../pragmarc mine_detector.adb gtkada-config gcc-4.4 -c -I../pragmarc -I/usr/share/ada/adainclude/gtkada2 mine_detector.adb gcc-4.4 -c -I../pragmarc -I/usr/share/ada/adainclude/gtkada2 user_if.adb gcc-4.4 -c -I../pragmarc -I/usr/share/ada/adainclude/gtkada2 field.ads gcc-4.4 -c -I../pragmarc -I/usr/share/ada/adainclude/gtkada2 field-operations.adb gnatbind -I../pragmarc -aI/usr/share/ada/adainclude/gtkada2 -aO/usr/lib/ada/adalib/gtkada2 -x mine_detector.ali gnatlink mine_detector.ali -L/usr/lib -lgtkada2 -pthread -lgtk-x11-2.0 -lgdk-x11-2.0 -latk-1.0 -lgio-2.0 -lpangoft2-1.0 -lpangocairo-1.0 -lgdk_pixbuf-2.0 -lm -lcairo -lpango-1.0 -lfreetype -lfontconfig -lgobject-2.0 -lgmodule-2.0 -lgthread-2.0 -lrt -lglib-2.0$

### 4 How to make Ada generate an exception on some ﬂoating points operations?

On Thu, 20 Nov 2008 12:09:41 +0100, Markus Schoepflin wrote:

> is it possible to influence the behaviour of GNAT regarding the handling of
> NANs? (Most importantly in the special case of division by zero.)
>
> We need to get exceptions whenever a NAN is generated, is this possible
> somehow? (For example by setting Machine_Overflow to True and recompiling
> the compiler itself.)

You can scrap IEEE stuff in favor of Ada semantics by declaring your own
floating-point [sub]type with a range specified. The compiler will be
forced to check values:

type Safe_Float is digits 6 range -10.0E10..+10.0E10;

or

subtype Safe_Float is Float range Float'Range;

then

X : Safe_Float := 1.0;
Y : Safe_Float := 0.0;
begin
Y := X / Y;
exception
when Error : others =>  -- Should print "range check failed"
Put_Line (Exception_Message (Error));
end;

--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

### 6 how to make simple Ada program

If gnat is not installed, install it (on linux) using something similar to

sudo apt-get install gnat-4.6

write the following code in ﬁle called hello_world.adb

compile using

gnatbind -x hello_world.ali

Run it using ./hello_world

### 7 Ada implementation of decimal representation of exp()

This is an Ada implementation of decimal representation of $$e$$ based on SPIGOT algorithm for $$\pi$$ by S. Rabinowitz & S. Wagon, The American Mathematical Monthly, March 1995.

This source ﬁle is here

### 8 Ada implementation of getopt()

This package is an Ada implementation of getopt() as speciﬁed by the document ”The Single UNIX Speciﬁcation, Version 2”, Copyright 1997 The Open Group

This source ﬁle is here

This is a test program of the above package. source code