pp_addpm({At=>'Top'},<<'EOD');

=head1 NAME

PDL::Ops - Fundamental mathematical operators

=head1 DESCRIPTION

This module provides the functions used by PDL to
overload the basic mathematical operators (C<+ - / *>
etc.) and functions (C<sin sqrt> etc.)

It also includes the function C<log10>, which should
be a perl function so that we can overload it!

Matrix multiplication (the operator C<x>) is handled
by the module L<PDL::Primitive|PDL::Primitive>.

=head1 SYNOPSIS

none

=cut

EOD

pp_addpm({At=>'Bot'},<<'EOPM');

=head1 AUTHOR

Tuomas J. Lukka (lukka@fas.harvard.edu),
Karl Glazebrook (kgb@aaoepp.aao.gov.au), 
Doug Hunt (dhunt@ucar.edu), 
Christian Soeller (c.soeller@auckland.ac.nz),
Doug Burke (burke@ifa.hawaii.edu),
and Craig DeForest (deforest@boulder.swri.edu).

=cut

EOPM

pp_addhdr('
#include <math.h>

/* MOD requires hackage to map properly into the positive-definite numbers. */
/* Note that this code causes some warning messages in the compile, because */
/* the unsigned data types always fail the ((foo)<0) tests.  I believe that */
/* gcc optimizes those tests away for those data types.  --CED 7-Aug-2002   */
/* Resurrect the old MOD operator as the unsigned BU_MOD to get around this. --DAL 27-Jun-2008 */
/* Q_MOD is the same as MOD except the internal casts are to longlong.  -DAL 18-Feb-2015 */
/* Also changed the typecast in MOD to (long), and added a N==0 conditional to BU_MOD. -DAL 06-Mar-2015 */

#define MOD(X,N) (  ((N) == 0)   ?    0   :   (   (X) - (ABS(N))  *  ((long     )((X)/(ABS(N))) + (   ( ((N) * ((long     )((X)/(N)))) != (X) )   ?   ( ( ((N)<0) ? 1 : 0 )  +  ( (((X)<0) ? -1 : 0)))  :  0 ))))
#define Q_MOD(X,N) (((N) == 0)   ?    0   :   (   (X) - (ABS(N))  *  ((long long)((X)/(ABS(N))) + (   ( ((N) * ((long long)((X)/(N)))) != (X) )   ?   ( ( ((N)<0) ? 1 : 0 )  +  ( (((X)<0) ? -1 : 0)))  :  0 ))))
#define BU_MOD(X,N)(((N) == 0)   ?    0   :   ( (X)-(N)*((int)((X)/(N))) ))
#define SPACE(A,B)   ( ((A)<(B)) ? -1 : ((A)!=(B)) )
#define ABS(A)       ( (A)>=0 ? (A) : -(A) )
#define NOTHING
');

sub protect_chars {
  my ($txt) = @_;
  $txt =~ s/>/E;gt#/g;
  $txt =~ s/</E;lt#/g;
  $txt =~ s/;/</g;
  $txt =~ s/#/>/g;
  return $txt;
}

# simple binary operators

sub biop {
    my ($name,$op,$swap,$doc,%extra) = @_;
    my $optxt = protect_chars ref $op eq 'ARRAY' ? $op->[1] : $op;
    $op = $op->[0] if ref $op eq 'ARRAY';

    if ($swap) {
	$extra{HdrCode} = << 'EOH';
  pdl *tmp;
  if (swap) {
    tmp = a;
    a = b;
    b = tmp;
 
  }
EOH
    }

    # handle exceptions
    my $badcode = '   ( $PDLSTATEISBAD(a) && $ISBAD(a()) )
                   || ( $PDLSTATEISBAD(b) && $ISBAD(b()) )';
    if ( exists $extra{Exception} ) {
	# NOTE This option is unused ($badcode is not set).
	#      See also `ufunc()`.
	delete $extra{Exception};
    }
    if( exists $extra{Comparison} && $PDL::Config{WITH_BADVAL} ) {
	# *append* to header
	$extra{HdrCode} .= <<'EOH';
           if(    PDL->get_pdl_badvalue(a) == 0 || PDL->get_pdl_badvalue(a) == 1
	       || PDL->get_pdl_badvalue(b) == 0 || PDL->get_pdl_badvalue(b) == 1 ) {

	          warn("Badvalue is set to 0 or 1. This will cause data loss when using badvalues for comparison operators.");

	   }
EOH
    }

    pp_def($name,
	   Pars => 'a(); b(); [o]c();',
	   OtherPars => 'int swap',
	   HandleBad => 1,
	   NoBadifNaN => 1,
	   Inplace => [ 'a' ], # quick and dirty solution to get ->inplace do its job
	   Code => 
	   "\$c() = \$a() $op \$b();",
	   BadCode => qq{
	       if ( $badcode  )
	           \$SETBAD(c());
	       else
	           \$c() = \$a() $op \$b();
	   },
	   CopyBadStatusCode =>
	   'if ( $BADFLAGCACHE() ) {
               if ( a == c && $ISPDLSTATEGOOD(a) ) {
                  PDL->propagate_badflag( c, 1 ); /* have inplace op AND badflag has changed */
               }
               $SETPDLSTATEBAD(c);
            }',
	   %extra,
	   Doc => << "EOD");
=for ref

$doc

=for example

   \$c = $name \$a, \$b, 0;     # explicit call with trailing 0
   \$c = \$a $op \$b;           # overloaded call
   \$a->inplace->$name(\$b,0);  # modify \$a inplace

It can be made to work inplace with the C<\$a-E<gt>inplace> syntax.
This function is used to overload the binary C<$optxt> operator.
Note that when calling this function explicitly you need to supply
a third argument that should generally be zero (see first example).
This restriction is expected to go away in future releases.

=cut

EOD
} # sub: biop()

#simple binary functions
sub bifunc {
    my ($name,$func,$swap,$doc,%extra) = @_;
    my $funcov = ref $func eq 'ARRAY' ? $func->[1] : $func;
    my $isop=0; if ($funcov =~ s/^op//) { $isop = 1; }
    my $funcovp = protect_chars $funcov;
    $func = $func->[0] if ref $func eq 'ARRAY';
    if ($swap) {
	$extra{HdrCode} .= << 'EOH';
  pdl *tmp;
  if (swap) {
    tmp = a;
    a = b;
    b = tmp;
  }
EOH
    }
    my $ovcall;
    # is this one to be used as a function or operator ?
    if ($isop) { $ovcall = "\$c = \$a $funcov \$b;    # overloaded use"; }
    else       { $ovcall = "\$c = $funcov \$a, \$b;    # overloaded use"; }


#a little dance to avoid the MOD macro warnings for byte & ushort datatypes
    my $codestr;
    my $badcodestr;
    if ($extra{unsigned}){
    $codestr = << "ENDCODE";
  types(BU) %{
  \$c() = BU_$func(\$a(),\$b());
  %}
  types(SLNFD) %{
  \$c() = $func(\$a(),\$b());
  %}
  types(Q) %{
  \$c() = Q_$func(\$a(),\$b());
  %}
ENDCODE
} else { 
   $codestr = "\$c() = $func(\$a(),\$b());";
   }
 delete $extra{unsigned}; #remove the key so it doesn't get added in pp_def.

 $badcodestr = 'if ( $ISBAD(a()) || $ISBAD(b()) )
	       $SETBAD(c());
	       else {' . $codestr . " } \n";
#end dance

    pp_def($name,
	   HandleBad => 1,
	   NoBadifNaN => 1,
	   Pars => 'a(); b(); [o]c();',
	   OtherPars => 'int swap',
	   Inplace => [ 'a' ], # quick and dirty solution to get ->inplace do its job
	   Code => $codestr,
	   BadCode => $badcodestr, 
	   CopyBadStatusCode =>
	   'if ( $BADFLAGCACHE() ) {
               if ( a == c && $ISPDLSTATEGOOD(a) ) {
                  PDL->propagate_badflag( c, 1 ); /* have inplace op AND badflag has changed */
               }
               $SETPDLSTATEBAD(c);
            }',
	   %extra,
	   Doc => << "EOD");
=for ref

$doc

=for example

   \$c = \$a->$name(\$b,0); # explicit function call
   $ovcall
   \$a->inplace->$name(\$b,0);     # modify \$a inplace

It can be made to work inplace with the C<\$a-E<gt>inplace> syntax.
This function is used to overload the binary C<$funcovp> function.
Note that when calling this function explicitly you need to supply
a third argument that should generally be zero (see first example).
This restriction is expected to go away in future releases.

=cut

EOD
} # sub: bifunc()

# simple unary functions and operators
sub ufunc {
    my ($name,$func,$doc,%extra) = @_;
    my $funcov = ref $func eq 'ARRAY' ? $func->[1] : $func;
    my $funcovp = protect_chars $funcov;
    $func = $func->[0] if ref $func eq 'ARRAY';

    # handle exceptions
    my $badcode = '$ISBAD(a())';
    if ( exists $extra{Exception} ) {
#	$badcode .= " || $extra{Exception}";
#	print "Warning: ignored exception for $name\n";
	# NOTE This option is unused ($badcode is commented out above).
	#      See also `biop()`.
	delete $extra{Exception};
    }

    # do not have to worry about propagation of the badflag when
    # inplace since only input piddle is a, hence its badflag
    # won't change
    # UNLESS an exception occurs...
    pp_def($name,
	   Pars => 'a(); [o]b()',
	   HandleBad => 1,
	   NoBadifNaN => 1,
	   Inplace => 1,
	   Code => 
	   "\$b() = $func(\$a());",
	   BadCode =>
	   'if ( ' . $badcode . ' )
	      $SETBAD(b());
	   else' . "\n  \$b() = $func(\$a());\n",
	   %extra,
	   Doc => << "EOD");
=for ref

$doc

=for example

   \$b = $funcov \$a;
   \$a->inplace->$name;  # modify \$a inplace

It can be made to work inplace with the C<\$a-E<gt>inplace> syntax.
This function is used to overload the unary C<$funcovp> operator/function.

=cut

EOD
} # sub: ufunc()

######################################################################

# we trap some illegal operations here -- see the Exception option
# note, for the ufunc()'s, the checks do not work too well
#    for unsigned integer types (ie < 0)
#
# XXX needs thinking about 
#    - have to integrate into Code section as well (so
#      12/pdl(2,4,0,3) is trapped and flagged bad)
#      --> complicated
#    - perhaps could use type %{ %} ?
#
# ==> currently have commented out the exception code, since
#     want to see if can use NaN/Inf for bad values
#     (would solve many problems for F,D types)
#
# there is an issue over how we handle comparison operators
# - see Primitive/primitive.pd/zcover() for more discussion
#

## arithmetic ops
# no swap
biop('plus','+',0,'add two piddles');
biop('mult','*',0,'multiply two piddles');

# all those need swapping
biop('minus','-',1,'subtract two piddles');
biop('divide','/',1,'divide two piddles', Exception => '$b() == 0' );

## note: divide should perhaps trap division by zero as well

## comparison ops
# need swapping
biop('gt','>',1,'the binary E<gt> (greater than) operation', Comparison => 1 );
biop('lt','<',1,'the binary E<lt> (less than) operation', Comparison => 1 );
biop('le','<=',1,'the binary E<lt>= (less equal) operation', Comparison => 1 );
biop('ge','>=',1,'the binary E<gt>= (greater equal) operation', Comparison => 1 );
# no swap required
biop('eq','==',0,'binary I<equal to> operation (C<==>)', Comparison => 1 );
biop('ne','!=',0,'binary I<not equal to> operation (C<!=>)', Comparison => 1 );

## bit ops
# those need to be limited to the right types
my $T = [B,U,S,L]; # the sensible types here
biop('shiftleft','<<',1,'leftshift C<$a> by C<$b>',GenericTypes => $T);
biop('shiftright','>>',1,'rightshift C<$a> by C<$b>',GenericTypes => $T);
biop('or2','|',0,'binary I<or> of two piddles',GenericTypes => $T);
biop('and2','&',0,'binary I<and> of two piddles',GenericTypes => $T);
biop('xor','^',0,'binary I<exclusive or> of two piddles',GenericTypes => $T);

# really an ufunc
ufunc('bitnot','~','unary bit negation',GenericTypes => $T);

# some standard binary functions
bifunc('power',['pow','op**'],1,'raise piddle C<$a> to the power C<$b>',GenericTypes => [D]);
bifunc('atan2','atan2',1,'elementwise C<atan2> of two piddles',GenericTypes => [D]);
bifunc('modulo',['MOD','op%'],1,'elementwise C<modulo> operation',unsigned=>1);
bifunc('spaceship',['SPACE','op<=>'],1,'elementwise "<=>" operation');

# some standard unary functions
ufunc('sqrt','sqrt','elementwise square root', Exception => '$a() < 0' );
ufunc('abs',['ABS','abs'],'elementwise absolute value',GenericTypes => [D,F,S,L]);
ufunc('sin','sin','the sin function');
ufunc('cos','cos','the cos function');
ufunc('not','!','the elementwise I<not> operation');
ufunc('exp','exp','the exponential function',GenericTypes => [D]);
ufunc('log','log','the natural logarithm',GenericTypes => [D], 
      Exception => '$a() <= 0' );

pp_export_nothing(); 

# make log10() work on scalars (returning scalars)
# as well as piddles
ufunc('log10','log10','the base 10 logarithm', GenericTypes => [D], 
      Exception => '$a() <= 0',
      PMCode => 
'
sub PDL::log10 { 
    my $x = shift; 
    if ( ! UNIVERSAL::isa($x,"PDL") ) { return log($x) / log(10); }
    my $y;
    if ( $x->is_inplace ) { $x->set_inplace(0); $y = $x; }
    elsif( ref($x) eq "PDL"){
    	#PDL Objects, use nullcreate:
	$y = PDL->nullcreate($x);
    }else{
    	#PDL-Derived Object, use copy: (Consistent with
	#  Auto-creation docs in Objects.pod)
	$y = $x->copy;
    }
    &PDL::_log10_int( $x, $y );
    return $y;
};
'
);

# note: the extra code that adding 'HandleBad => 1' creates is
# unneeded here. Things could be made clever enough to work this out,
# but it's very low priority.
# It does add doc information though, and lets people know it's been
# looked at for bad value support
# DJB adds: not completely sure about this now that I have added code
# to avoid a valgrind-reported error (see the CacheBadFlagInit rule
# in PP.pm)
#
# Can't this be handled in Core.pm when '.=' is overloaded ?
#
pp_def(
       'assgn',
#       HandleBad => 1,
       Pars => 'a(); [o]b();',
       Code =>
       '$b() = $a();',
#       BadCode =>
#       'if ( $ISBAD(a()) ) { $SETBAD(b()); } else { $b() = $a(); }',
       Doc =>
'Plain numerical assignment. This is used to implement the ".=" operator',
); # pp_def assgn

#pp_export_nothing(); 

pp_done();