Add variable_to_index method

Author: Jake-Moss

src/flint/flint_base/flint_base.pyx

@@ -164,6 +164,23 @@ cdef class flint_mpoly_context(flint_elem):
     def gens(self):
         return tuple(self.gen(i) for i in range(self.nvars()))
 
+    def variable_to_index(self, var: Union[int, str]):
+        """Convert a variable name string or possible index to it's index in the context."""
+        if isinstance(var, str):
+            vars = {x: i for i, x in enumerate(self.names())}
+            if var not in vars:
+                raise ValueError("Variable not in context")
+            else:
+                i = vars[var]
+        elif isinstance(var, int):
+            if not 0 <= var < self.nvars():
+                raise IndexError("Generator index out of range")
+            i = var
+        else:
+            raise TypeError("Invalid variable type")
+
+        return i
+
     @staticmethod
     def create_variable_names(slong nvars, names: str):
         """

src/flint/types/fmpq_mpoly.pyx

@@ -903,20 +903,7 @@ cdef class fmpq_mpoly(flint_mpoly):
         """
         cdef:
             fmpq_mpoly res
-            slong i = 0
-
-        if isinstance(var, str):
-            vars = {x: i for i, x in enumerate(self.ctx.names())}
-            if var not in vars:
-                raise ValueError("variable not in context")
-            else:
-                i = vars[var]
-        elif isinstance(var, int):
-            if not 0 <= var < self.ctx.nvars():
-                raise IndexError("generator index out of range")
-            i = <slong>var
-        else:
-            raise TypeError("invalid variable type")
+            slong i = self.ctx.variable_to_index(var)
 
         res = create_fmpq_mpoly(self.ctx)
 
@@ -942,20 +929,7 @@ cdef class fmpq_mpoly(flint_mpoly):
         """
         cdef:
             fmpq_mpoly res
-            slong i = 0
-
-        if isinstance(var, str):
-            vars = {x: i for i, x in enumerate(self.ctx.names())}
-            if var not in vars:
-                raise ValueError("variable not in context")
-            else:
-                i = vars[var]
-        elif isinstance(var, int):
-            if not 0 <= var < self.ctx.nvars():
-                raise IndexError("generator index out of range")
-            i = <slong>var
-        else:
-            raise TypeError("invalid variable type")
+            slong i = self.ctx.variable_to_index(var)
 
         res = create_fmpq_mpoly(self.ctx)
 

src/flint/types/fmpz_mpoly.pyx

@@ -915,20 +915,7 @@ cdef class fmpz_mpoly(flint_mpoly):
         """
         cdef:
             fmpz_mpoly res
-            slong i = 0
-
-        if isinstance(var, str):
-            vars = {x: i for i, x in enumerate(self.ctx.names())}
-            if var not in vars:
-                raise ValueError("variable not in context")
-            else:
-                i = vars[var]
-        elif isinstance(var, int):
-            if not 0 <= var < self.ctx.nvars():
-                raise IndexError("generator index out of range")
-            i = <slong>var
-        else:
-            raise TypeError("invalid variable type")
+            slong i = self.ctx.variable_to_index(var)
 
         res = create_fmpz_mpoly(self.ctx)
 
@@ -955,20 +942,7 @@ cdef class fmpz_mpoly(flint_mpoly):
         cdef:
             fmpz_mpoly res
             fmpz scale
-            slong i = 0
-
-        if isinstance(var, str):
-            vars = {x: i for i, x in enumerate(self.ctx.names())}
-            if var not in vars:
-                raise ValueError("variable not in context")
-            else:
-                i = vars[var]
-        elif isinstance(var, int):
-            if not 0 <= var < self.ctx.nvars():
-                raise IndexError("generator index out of range")
-            i = <slong>var
-        else:
-            raise TypeError("invalid variable type")
+            slong i = self.ctx.variable_to_index(var)
 
         res = create_fmpz_mpoly(self.ctx)