在lisp中从double-float创建一个单浮点数组？(Create an array of single-float from double-float in lisp?)

 当我尝试像这样创建一个单浮点数组时，我得到： 
 
(make-array 2 :element-type 'single-float :initial-contents #(3.0 4.0))
 
 ，我收到以下错误： 
 
The value 3.0 is not of type SINGLE-FLOAT
 
 有没有办法从一个简单的double-float向量创建单浮点数组？ 

When I try to create a single-float array like this, i get:
 
(make-array 2 :element-type 'single-float :initial-contents #(3.0 4.0))
 
, i get the following error:
 
The value 3.0 is not of type SINGLE-FLOAT
 
Is there a way to create a single-float array from a simple vector of double-float?

原文：https://stackoverflow.com/questions/28767387