codegen for susy process fails with "ValueError : not enough values to unpack (expected 2, got 1)"

[valassi]

The codegen for a susy process fails with "ValueError : not enough values to unpack (expected 2, got 1)"

This is an issue that I just discussed with @oliviermattelaer . IIUC this had also been reported by @nscottnichols in a similar setup. Copying also @zeniheisser for info.

We had a look with Olivier. This comes from the codegen for HRDCOD=1. The issue is that the original code includes not only "parameter = value" but also "if ( condition ) parameter = value".

A first quick fix in model_handling.py could be

         parset_lines = {}
         for line in parset.split('\n'):
+            if line.startswith('if'): continue
             par, parval = line.split(' = ')

However then I get an assert in

        assert( len(pardef_lines) == len(parset_lines) ) # AV sanity check (same number of parameters)

I must look at the unmodified code and see what it gives... with HRDCOD=1 we need constexpr stuff, so the counting of parameters must be handled with care...

[valassi]

I have two sort of issues now

First, the error above probably come from this code, which I find puzzling

763 if ( mdl_Mneu2 < 0 )
764 mdl_Wneu2 = -abs( mdl_Wneu2 );
765 if ( mdl_Mneu3 < 0 )
766 mdl_Wneu3 = -abs( mdl_Wneu3 );
767 if ( mdl_Mneu4 < 0 )
768 mdl_Wneu4 = -abs( mdl_Wneu4 );
769 if ( mdl_Mgo < 0 )
770 mdl_Wgo = -abs( mdl_Wgo );

What is the point of saying if ( x < 0 ) x = -abs ( x )? Is this not a tautology?!

Second, I need to understand what the slha.get_block_entry does when there are indices...

34 indices[0] = 3;
35 indices[1] = 3;
36 mdl_Ryu3x3 = slha.get_block_entry( "yu",  indices,  8.928445e-01 );

[nscottnichols]

Just commenting to say, this is indeed the same issue I ran into with a similar setup (after Olivier's changes). You can get to the same issue generating pp_t1t1.

[valassi]

First, the error above probably come from this code, which I find puzzling

763 if ( mdl_Mneu2 < 0 )
764 mdl_Wneu2 = -abs( mdl_Wneu2 );
765 if ( mdl_Mneu3 < 0 )
766 mdl_Wneu3 = -abs( mdl_Wneu3 );
767 if ( mdl_Mneu4 < 0 )
768 mdl_Wneu4 = -abs( mdl_Wneu4 );
769 if ( mdl_Mgo < 0 )
770 mdl_Wgo = -abs( mdl_Wgo );

What is the point of saying if ( x < 0 ) x = -abs ( x )? Is this not a tautology?!

Ouf. More complex than I thought. I read it incorrectly, the code makes sense, they are two different variables M and W. So the code must be included...

In addition, code generation of that snippet is puzzling. It seems to come from super().write_set_parameters([]) with an empty list as argument?... This gives issues elsewhere

[valassi]

Ok at least this one seems easy now that I analysed it better. I just need to replace this whole function

    def write_set_parameters(self, params):
        """Write out the lines of independent parameters"""

        # For each parameter, write name = expr;

        res_strings = []
        for param in params:
            res_strings.append("%s" % param.expr)

        # Correct width sign for Majorana particles (where the width
        # and mass need to have the same sign)        
        for particle in self.model.get('particles'):
            if particle.is_fermion() and particle.get('self_antipart') and \
                   particle.get('width').lower() != 'zero':
                res_strings.append("if (%s < 0)" % particle.get('mass'))
                res_strings.append("%(width)s = -abs(%(width)s);" % \
                                   {"width": particle.get('width')})

        return "\n".join(res_strings)