class_docstr: Turn a vector into a diagonal matrix.
code: def doit(self, **hints):
      from sympy.assumptions import ask, Q
      from sympy.matrices.expressions.matmul import MatMul
      from sympy.matrices.expressions.transpose import Transpose
      from sympy.matrices.dense import eye
      from sympy.matrices.matrixbase import MatrixBase
  
      vector = self._vector
      # This accounts for shape (1, 1) and identity matrices, among others:
      if ask(Q.diagonal(vector)):
          return vector
      if isinstance(vector, MatrixBase):
          ret = eye(max(vector.shape))
          for i in range(ret.shape[0]):
              ret[i, i] = vector[i]
          return type(vector)(ret)
      if vector.is_MatMul:
          matrices = [arg for arg in vector.args if arg.is_Matrix]
          scalars = [arg for arg in vector.args if arg not in matrices]
          if scalars:
              return (
                  Mul.fromiter(scalars)
                  * DiagMatrix(MatMul.fromiter(matrices).doit()).doit()
              )
      if isinstance(vector, Transpose):
          vector = vector.arg
      return DiagMatrix(vector)
  
imports: from sympy.core.sympify import _sympify
  from sympy.matrices.expressions import MatrixExpr
  from sympy.core import S, Eq, Ge
  from sympy.core.mul import Mul
  from sympy.functions.special.tensor_functions import KroneckerDelta
label_desc: Use image node_id 6 for calling the DiagMatrix obj's underlying member method code with example usage: obj.doit() and returns: DiagMatrix, vector, type, unknown