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I want to define a function over a dynamic number of variables, but find no way to coerce list, tuple or string to symbolic ring. Is there some Python / pre-parse / magic which can make this work? A failed example follows: sage: var( 'x1 x2 x3' ) sage: function('xxx')(x1,x2) # A function of a fixed, pre-programmed number of variables xxx(x1, x2) sage: n = 3 sage: ' '.join('x'+str(i+1) for i in range(n)) # A string 'x1 x2 x3' sage: eval( ' '.join('x'+str(i+1)+',' for i in range(n)) ) # A tuple (x1, x2, x3) sage: function('yyy')( eval( ' '.join('x'+str(i+1)+',' for i in range(n)) ) ) Traceback (most recent call last): ... TypeError: cannot coerce arguments: no canonical coercion from <type 'tuple'> to Symbolic Ring

I want to define a function over a dynamic number of variables, but find no way to coerce list, tuple or string to symbolic ring. Is there some Python / pre-parse / magic which can make this work? A failed example follows: follows

sage: var( 'x1 x2 x3' ) sage: function('xxx')(x1,x2) # A function of a fixed, pre-programmed number of variables xxx(x1, x2) sage: n = 3 sage: ' '.join('x'+str(i+1) for i in range(n)) # A string 'x1 x2 x3' sage: eval( ' '.join('x'+str(i+1)+',' for i in range(n)) ) # A tuple (x1, x2, x3) sage: function('yyy')( eval( ' '.join('x'+str(i+1)+',' for i in range(n)) ) ) Traceback (most recent call last): ... TypeError: cannot coerce arguments: no canonical coercion from <type 'tuple'> to Symbolic Ring

I want to define a function over a dynamic number of variables, but find no way to coerce list, tuple or string to symbolic ring. Is there some Python / pre-parse / magic which can make this work? A failed example follows

 sage: var( 'x1 x2 x3' )  
sage: function('xxx')(x1,x2)    # A function of a fixed, pre-programmed number of variables  
 xxx(x1, x2)  
sage: n = 3  
sage: ' '.join('x'+str(i+1) for i in range(n))    # A string  
 'x1 x2 x3'  
sage: eval( ' '.join('x'+str(i+1)+',' for i in range(n)) )    # A tuple  
 (x1, x2, x3)  
sage: function('yyy')( eval( ' '.join('x'+str(i+1)+',' for i in range(n)) ) )  
 Traceback (most recent call last):  
 ...  
 TypeError: cannot coerce arguments: no canonical coercion from <type 'tuple'> to Symbolic Ring  
Ring